ArticleLiterature Review

Dietary protein for athletes: From requirements to optimum adaptation

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Abstract

Opinion on the role of protein in promoting athletic performance is divided along the lines of how much aerobic-based versus resistance-based activity the athlete undertakes. Athletes seeking to gain muscle mass and strength are likely to consume higher amounts of dietary protein than their endurance-trained counterparts. The main belief behind the large quantities of dietary protein consumption in resistance-trained athletes is that it is needed to generate more muscle protein. Athletes may require protein for more than just alleviation of the risk for deficiency, inherent in the dietary guidelines, but also to aid in an elevated level of functioning and possibly adaptation to the exercise stimulus. It does appear, however, that there is a good rationale for recommending to athletes protein intakes that are higher than the RDA. Our consensus opinion is that leucine, and possibly the other branched-chain amino acids, occupy a position of prominence in stimulating muscle protein synthesis; that protein intakes in the range of 1.3-1.8 g · kg(-1) · day(-1) consumed as 3-4 isonitrogenous meals will maximize muscle protein synthesis. These recommendations may also be dependent on training status: experienced athletes would require less, while more protein should be consumed during periods of high frequency/intensity training. Elevated protein consumption, as high as 1.8-2.0 g · kg(-1) · day(-1) depending on the caloric deficit, may be advantageous in preventing lean mass losses during periods of energy restriction to promote fat loss.

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... Nutrition education, including how athletes should use the plate, along with menu labeling with nutrition facts highlighting protein, could avoid this issue. Third, recent rising trends in protein requirements for athletes (Hector & Phillips, 2017;Phillips et al., 2016;Phillips & Van Loon, 2011) may have influenced the RDs who built the plates in this study. ...
... Considering protein intake in athletes, the recent focus has not only been on quantity, but also the timing of ingestion relative to exercise (Areta et al., 2013;Macnaughton et al., 2016;Res et al., 2012) to optimize recovery and muscle anabolism. The current recommendation for athletes is to consume 0.3 g·kg −1 BM·day −1 or 20-25 g of protein per meal, four to five times per day Phillips & Van Loon, 2011), some of which is likely to be consumed postexercise in the form of a snack (Abbey et al., 2017;Parnell et al., 2016;Whitehouse & Lawlis, 2017). Thus, if anything, this study likely underestimates the protein content. ...
... Similar results have been observed in this study, with higher protein content observed at L and D versus B. This suggests that more efforts have to be directed at educating athletes on how to distribute protein throughout the day, considering the timing of their training sessions and the digestibility of different protein sources. Another factor to consider is the protein quality (Pennings et al., 2011;Phillips & Van Loon, 2011;Res et al., 2012). It has been demonstrated that a good quality protein with a high leucine content will help with recovery and training adaptation (Macnaughton et al., 2016;Pennings et al., 2011;Phillips & Van Loon, 2011;Rowlands et al., 2014). ...
... [8] Athletes' needs are dependent on training status; however, a protein intake of 1.2-1.7 g per kg per day is sufficient for endurance and resistance-trained athletes. [9] However, surveys of athletes indicate that they commonly consume more than the aforementioned requirement. [9] An Italian study [10] performed in 2011 before the IARC classification that assessed the eating behaviors of gym users and focused on supplement use indicated that athletes who used protein supplements also had a higher intake of protein-rich food, with a particular preference for meat. ...
... [9] However, surveys of athletes indicate that they commonly consume more than the aforementioned requirement. [9] An Italian study [10] performed in 2011 before the IARC classification that assessed the eating behaviors of gym users and focused on supplement use indicated that athletes who used protein supplements also had a higher intake of protein-rich food, with a particular preference for meat. [10] Therefore, gym users seem to be at a greater risk of exceeding the recommended intake based on the above studies [9][10] that appear to indicate a higher meat intake among them. ...
... [9] An Italian study [10] performed in 2011 before the IARC classification that assessed the eating behaviors of gym users and focused on supplement use indicated that athletes who used protein supplements also had a higher intake of protein-rich food, with a particular preference for meat. [10] Therefore, gym users seem to be at a greater risk of exceeding the recommended intake based on the above studies [9][10] that appear to indicate a higher meat intake among them. Factors other than sports can potentially affect RM and PM consumption, such as sociodemographic variables, dietary behaviors, and knowledge of the potential risks of RM and PM consumption. ...
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Background: Consumption of red meat (RM) and processed meat (PM) is associated with the development of colorectal cancer (CRC). Gym users use RM and PM as supplements for their workouts. This puts them at risk of developing cancer. Method: Self-administered questionnaires were used to evaluate the level of awareness, eating behaviors, and potential risks associated with specific foods among gym users in Saudi Arabia from November 2021 to August 2022. Demographic factors were also assessed, the questionnaire was distributed using online platforms including WhatsApp and Twitter. Results: In our study, 41.2% (n=123) and 70.8% (n=211) of the participants rarely consumed RM and PM per week, with the highest consumption of less than 500 g per week 31.9% (n=95) for RM. Only 7.4% (n=22) exceeded 1000 g of weekly RM and PM consumption. Maleness, high protein intake (>200 g/day), supplementary protein intake, good income (>5000 SAR) and being a healthcare worker were associated with higher RM consumption. In contrast, being a dietitian or sports coach was associated with less PM (p=0.045) consumption. The overwhelming majority of subjects 81.2% (n=242) had never heard of nitrites and N-nitroso compounds; knowing about these compounds and their carcinogenic potential was associated with a lower RM consumption (p=0.033). Conclusion: More educational campaigns on RM and PM are needed to address the lack of understanding of their associated risks, especially for male athletes and people with good socioeconomic status.
... Other reports take account of physiological variables such as protein digestion and amino acid absorption which, together, dictate peripheral leucine availability following protein ingestion and, thus, a stimulus actually seen by the muscle (i.e., "leucine trigger" concept; Tang et al., 2009;West et al., 2011). However, even within this more sophisticated view, it is unclear whether the peak concentration West et al., 2011), rate of rise (Phillips & Van Loon, 2011;West et al., 2011), or total postprandial availability of plasma (Oikawa et al., 2020; or even intramuscular unbound) leucine is the prime "trigger." A recent qualitative systematic review (Zaromskyte et al., 2021) supported the utility of the leucine trigger hypothesis within muscle of older individuals and during studies where crystalline amino acid mixtures or isolated proteins were ingested. ...
... What is generally referred to as the "leucine threshold" hypothesis posits a simple dose-response relationship between total leucine ingested and the postprandial postexercise MPS response, plateauing at around ~2.5 g (Witard et al., 2014). This is aligned with various applied sports nutrition recommendations to ingest a protein meal containing at least 2-3 g leucine in close temporal proximity to exercise to maximize the postexercise muscle anabolic response (Collins et al., 2021;Dickinson et al., 2013;Katsanos et al., 2006;Morgan et al., 2022;Phillips & Van Loon, 2011;Wall, Morton, et al., 2015). Our present data do not fully support this concept. ...
... The utility of comparing leucine dose to postexercise MPS responses does not account for the multitude of mediating physiological factors that could mechanistically modulate this relationship. Attempts have been made to link the two, generally encompassed within the umbrella term "leucine trigger" hypothesis (Phillips & Van Loon, 2011;Witard et al., 2014;Zaromskyte et al., 2021). We show that leucine dose strongly predicts various postprandial candidate "triggers," such as peak plasma leucine magnitude ( Figure 3; Norton et al., 2009;Pennings, Boirie, et al., 2011;Tang et al., 2009;West et al., 2011), the rate of rise to peak plasma leucine magnitude (Figure 4; Wall et al., 2013), and total postprandial plasma leucine availability (iAUC; Figure 5, Mitchell, Phillips, et al., 2015). ...
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Background Dietary protein ingestion augments post (resistance) exercise muscle protein synthesis (MPS) rates. It is thought that the dose of leucine ingested within the protein (leucine threshold hypothesis) and the subsequent plasma leucine variables (leucine trigger hypothesis; peak magnitude, rate of rise, and total availability) determine the magnitude of the postprandial postexercise MPS response. Methods A quantitative systematic review was performed extracting data from studies that recruited healthy adults, applied a bout of resistance exercise, ingested a bolus of protein within an hour of exercise, and measured plasma leucine concentrations and MPS rates (delta change from basal). Results Ingested leucine dose was associated with the magnitude of the MPS response in older, but not younger, adults over acute (0–2 h, r ² = 0.64, p = 0.02) and the entire postprandial (>2 h, r ² = 0.18, p = 0.01) period. However, no single plasma leucine variable possessed substantial predictive capacity over the magnitude of MPS rates in younger or older adults. Conclusion Our data provide support that leucine dose provides predictive capacity over postprandial postexercise MPS responses in older adults. However, no threshold in older adults and no plasma leucine variable was correlated with the magnitude of the postexercise anabolic response.
... The most crucial aspect in a sports diet is the energy intake; satisfying the energy requirement is a nutritional priority for all athletes [4,5,25,54]. An inadequate energy intake cancels the benefits of training, hinders performance, and can lead to health complications such as a loss of muscle mass and/or bone density, as well as an increased risk of overtraining, injuries, and illnesses [25,40]. ...
... Emerging research on athletes' PRO requirements suggests that dietary PROs "interact" with exercise by providing not only a substrate for the synthesis of contractile, structural, and metabolic proteins, but also for the stimulation of muscle protein synthesis [5,25]. Consuming a variety of plant protein sources throughout the day ensures that all essential amino acids are obtained as long as energy needs are met [39]. ...
... It is also important to note that, contrary to what was once believed, vegetarians do not need to consume specific combinations of plant proteins in each meal, but should consume a variety of protein sources distributed throughout the 24 h [2,69]. An exception may be considered for the postworkout period for athletes who perform intense strength training: in this phase, to support and optimize muscle protein synthesis, it is useful to "provide" leucine and about 10 g of essential amino acids [5,25]. Many plant proteins, including legumes, are rich in leucine, although not as bioavailable as those found in whey proteins. ...
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Background: Nutrition strategies improve physiological and biochemical adaptation to training, facilitate more intense workouts, promote faster recoveries after a workout in anticipation of the next, and help to prepare for a race and maintain the body's hydration status. Although vegetarianism (i.e., lacto-ovo and veganism) has become increasingly popular in recent years, the number of vegetarian athletes is not known, and no specific recommendations have been made for vegetarian dietary planning in sports. Well-planned diets are mandatory to obtain the best performance, and the available literature reports that those excluding all types of flesh foods (meat, poultry, game, and seafood) neither find advantages nor suffer from disadvantages, compared to omnivorous diets, for strength, anaerobic, or aerobic exercise performance; additionally, some benefits can be derived for general health. Methods: We conceived the VegPlate for Sports, a vegetarian food guide (VFG) based on the already-validated VegPlate facilitating method, designed according to the Italian dietary reference intakes (DRIs). Results: The VegPlate for Sports is suitable for men and women who are active in sports and adhere to a vegetarian (i.e., lacto-ovo and vegan) diet, and provides weight-based, adequate dietary planning. Conclusions: The VegPlate for Sports represents a practical tool for nutrition professionals and gives the possibility to plan diets based on energy, carbohydrate (CHO), and protein (PRO) necessities, from 50 to 90 Kg body weight (BW).
... De eiwitbehoefte kan hoog zijn bij zowel intensieve kracht-als duurinspanning. Bij krachttraining is er sprake van een verhoogde eiwitbehoefte, omdat dergelijke inspanning in combinatie met de consumptie van eiwit de spiereiwitsynthese stimuleert, spierafbraak vermindert en spierschade herstelt (Phillips & Van Loon 2011). Spiereiwitafbraak is verhoogd na inspanning, maar in verhouding lager dan spiereiwitsynthese mits een adequate hoeveelheid eiwit en specifieke aminozuren wordt geconsumeerd. ...
... Spiereiwitafbraak is verhoogd na inspanning, maar in verhouding lager dan spiereiwitsynthese mits een adequate hoeveelheid eiwit en specifieke aminozuren wordt geconsumeerd. Wanneer spiereiwitsynthese groter is dan spiereiwitafbraak zal dat resulteren in een positieve spiereiwitbalans na inspanning (Biolo et al. 1995(Biolo et al. , 1999Phillips & Van Loon 2011). ...
... Hoewel veel onderzoek naar het effect van eiwit bij krachtsporters is gedaan, zijn eiwitten ook bij duursporters van groot belang. Bij duurinspanning is er sprake van een verhoogde eiwitbehoefte, omdat tijdens duurtraining een verhoogde oxidatie van het aminozuur leucine plaatsvindt (Phillips & Van Loon 2011) . Daarnaast zijn eiwitten een onmisbaar substraat voor duurtrainingspecifieke trainingsadaptaties . ...
... In relation to protein intake, omnivores consume 9.2% more protein than vegetarians [26]. In relation to endurance athletes, the recommended intake is between 1.2 and 1.7 g/kg/day [35]. Protein intake during the first three months of the season represents 20.37% of the total energy intake, and, in months 6 and 9, it increases to 21.7%, which corresponds to 2.2 g/kg/day [32]. ...
... Furthermore, total and saturated fat consumption is higher in omnivores than in vegetarians, 7.1% and 136.5%, respectively [26,28] (Figures 9 and 10). The amount required for endurance athletes is 2 g/kg/day or 1.6 g/kg/day [32,35]. The average intake of essential fatty acids in endurance athletes is increased by 4% during the third and sixth months of the season [32]. ...
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Introduction: In recent years, the vegetarian diet has increased in popularity among athletes. The aim of this review is to ascertain the differences in variables related to performance, nutritional intake, and health in athletes according to whether they are omnivores or vegetarians. Methodology: A literature search was carried out in different databases: PubMed, Web of Science, Dialnet, and Cochrane. The keywords used were "vegetarian diet", "vegan diet", "exercise", "sport", and "performance". After applying different inclusion criteria, six studies were included in the review. Results: No significant differences were obtained in variables related to physical performance (adherence exercise, Vo2Máx, muscle power, and sprint test) or health (body composition, psychological well-being, and social relationships), but dietary intake was significantly higher in carbohydrates and lower in proteins in vegetarian athletes (p < 0.05). Conclusions: It cannot be affirmed that vegetarian subjects have a higher sports performance, for which more research should be carried out.
... ) , so monitoring changes in LBM, indicative of nutritional status, can provide insight into the effectiveness of the training programme being undertaken on(Zapolska et al., 2014) 46) an overall level and also on an individual basis 47) .It has been commonly recommended that the energy intake of athletes involved in moderate levels of training, such as elite basketball players (2-3 h/day for 5-6 times/week), should be 50-80 kcal·(kg·day) -1(Scanlan et al., 2015) 2) , with specific recommendations of 1.6-1.8 g·(kg·day) -1 for protein(Phillips & Van Loon, 2011) 48) . The ASCM recommends that physically active women consume 1.2-2 g·(kg·day) -1 of protein (Thomas et al., 2016) 49) , while fat intake should be 20-35% of total kilocalorie intake (Rodríguez et al., 2009) 50) and 5-8 g·(kg·day) -1 of CHO (Scanlan et al., 2015) 2) to adequately meet performance demands. ...
... ) , so monitoring changes in LBM, indicative of nutritional status, can provide insight into the effectiveness of the training programme being undertaken on(Zapolska et al., 2014) 46) an overall level and also on an individual basis 47) .It has been commonly recommended that the energy intake of athletes involved in moderate levels of training, such as elite basketball players (2-3 h/day for 5-6 times/week), should be 50-80 kcal·(kg·day) -1(Scanlan et al., 2015) 2) , with specific recommendations of 1.6-1.8 g·(kg·day) -1 for protein(Phillips & Van Loon, 2011) 48) . The ASCM recommends that physically active women consume 1.2-2 g·(kg·day) -1 of protein (Thomas et al., 2016) 49) , while fat intake should be 20-35% of total kilocalorie intake (Rodríguez et al., 2009) 50) and 5-8 g·(kg·day) -1 of CHO (Scanlan et al., 2015) 2) to adequately meet performance demands. ...
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Basketball is a popular team sport worldwide. Nutrition is one of the key aspects for the optimization of performance and subsequent recovery. Female athletes have unique nutritional requirements as a result of daily training and competition, in addition to the specific demands of gender-related physiological changes. However, inadequate, or erroneous nutritional behaviours are commonly observed. Thus, the aim of our work is to provide concise nutritional recommendations for female basketball players. Based on a review of the literature, there is limited evidence that comprehensively assesses health attributes as well as behaviours, habits, and nutritional knowledge of physical activity by gender in basketball players. Recent research highlights the need for nutritional strategies to develop tools to help manage energy deficiency in women’s sports. We suggest that individual adjustment of dietary energy value is the key factor in the physical performance of female basketball players; information that could be used to optimize the training process and health maintenance. The recommended intake for athletes involved in moderate levels of training, such as elite basketball players (2-3 h/day for 5-6 times/week), is 50-80 kcal·(kg·day)⁻¹, with specific recommendations of 1.6-1.8 g·(kg·day)⁻¹ protein. For physically active women, it is recommended that 1.2-2 g·(kg·day)⁻¹ of protein be consumed, with fat intake of 20-35% of total kilocalories and 5-8 g·(kg·day)⁻¹ of carbohydrate to adequately meet performance demands.
... Direnç antrenmanlı sporcularda büyük miktarlarda günlük protein tüketiminin arkasındaki ana inanç, bunun daha fazla kas proteini üretmek için gerekli olduğudur. Kas kütlesinin korunması, kas protein sentezi (KPS) ve kas protein yıkımı (KPY) arasındaki dengedir (Stuart & Luc, 2011). Enerji metabolizmasına protein katkısı %1-1,5 arasında değişmektedir. ...
... Antrenmanın sonunda protein alımı, yeni kas proteinlerinin sentezini ve pozitif bir nitrojen dengesinin yanı sıra mitokondriyal adaptasyonları ve artan glikojen yeniden sentezleme kapasitesini destekler. Ayrıca antrenmanı takiben protein alımı, kreatin kinaz salınımı gibi hasar belirtilerini azaltır (Stuart & Luc, 2011). Bununla birlikte, serum lösin konsantrasyonları ve miyofibriler protein sentezinin arttığı lösin eşikleri ile ilişkili olan protein alımının anabolik etkileri, protein kaynağının kalitesine ve miktarına bağlıdır. ...
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... It has been well established that athletes require a well-planned protein distribution to support their training as well as post-exercise recovery and adaptation, especially in skeletal muscles (28). According to current research, the recommended dietary protein intake to facilitate metabolic adaptation, repair, remodeling, and overall protein turnover typically ranges from 1.2 to 2.0 g/kg/d (29). Ingesting approximately 20 g to 30 g of total protein during exercise or the subsequent recovery period has been shown to enhance whole-body and muscle protein synthesis and improve nitrogen balance (29). ...
... According to current research, the recommended dietary protein intake to facilitate metabolic adaptation, repair, remodeling, and overall protein turnover typically ranges from 1.2 to 2.0 g/kg/d (29). Ingesting approximately 20 g to 30 g of total protein during exercise or the subsequent recovery period has been shown to enhance whole-body and muscle protein synthesis and improve nitrogen balance (29). Trakman and colleagues utilized a speci c question within the SNK section to evaluate the approximate daily protein requirements of well-trained resistance athletes (30). ...
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Background: Satisfactory nutrition knowledge among athletes is important to encourage proper dietary habits to overcome deficiencies and enhance sports performance. Identifying knowledge gaps in sports nutrition is essential for improving athletes' understanding, ideally through a contemporary tool that evaluates both general nutrition knowledge (GNK) and sports nutrition knowledge (SNK). This study aims to develop the Athletic Sports Nutrition Knowledge Questionnaire (A-SNKQ) specifically for Sri Lankan track and field athletes. Methods: The development of the A-SNKQ followed an extensive step-wise approach. Firstly, a systematic literature review was conducted on existing SNK questionnaires for athletes. Secondly, sports nutrition guidelines were incorporated into the questionnaire. Thirdly, information from local literature was gathered to ensure contextual relevance. Lastly, a qualitative study involving key athletic stakeholders was conducted to gain cultural insights. Additional processes were implemented to format and translate the tool. Results: The final version of the questionnaire consists of 33 questions, categorized into 12 sub-sections under two main sections: GNK (n = 16) and SNK (n = 17). The GNK section covers topics such as macronutrients, micronutrients, energy balance, hydration, and weight management. The SNK section addresses specific areas related to sporting performance, including carbohydrate loading, pre-training meals, meals during training, post-training meals, sports supplements, supplement label reading, alcohol consumption, isotonic drinks, doping, and relative energy deficiency syndrome in sports (RED-S). The questionnaire utilizes two question formats, namely single-best response questions and multiple-choice questions. In addition, three sports supplement labels were included. Conclusions: The GNK section of the A-SNKQ addresses the fundamental nutritional concepts. Conversely, the SNK focuses on the knowledge associated with sporting performance among track and field athletes.
... É essencial garantir que esses produtos sejam produzidos de acordo com padrões de qualidade e que não contenham substâncias proibidas ou potencialmente prejudiciais à saúde. A falta de regulamentação rigorosa nesse setor pode representar riscos para os consumidores (Phillips et al., 2011). ...
... O uso excessivo ou desregulado desses suplementos pode levar a efeitos colaterais indesejados, como aumento da frequência cardíaca, nervosismo, irritabilidade e insônia. Portanto, é importante seguir as orientações de uso e consultar um profissional de saúde antes de iniciar o uso desses suplementos(Phillips et al., 2011). ...
Article
Este artigo abordou a utilização de suplementos por praticantes de musculação, destacando seu papel como complemento para melhorar o desempenho, a recuperação e os resultados estéticos. Os suplementos podem fornecer nutrientes específicos que beneficiam o desenvolvimento muscular, a redução da fadiga e a melhoria do desempenho atlético. No entanto, é importante ressaltar que eles não substituem uma alimentação equilibrada e um programa de treinamento adequado. A segurança, a eficácia e a qualidade dos suplementos devem ser consideradas, buscando orientação profissional e informações confiáveis. Cada indivíduo é único, e é essencial adaptar a utilização de suplementos às necessidades individuais. Uma abordagem equilibrada, priorizando uma alimentação saudável e o treinamento consistente, é fundamental para alcançar os resultados desejados. Os suplementos devem ser vistos como uma ferramenta adicional, utilizados de forma consciente e responsável, em conjunto com uma abordagem global de saúde e bem-estar.
... comprising 20 to 30% of the total energy value of the diet [5][6][7]. And for athletes who need to optimize performance, the carbohydrate recommendation is within the range of 5 to 10 g/ kg -1 body weight/day -1 and in this case the protein can reach the highest range of the recommendation and go up to 4 g/kg -1 body weight/day -1 [8,9]. This way, a strategy refeeding days model was proposed by the author in Table 1, as a strategy that can be used to decrease the body fat percentage of the elite soccer player with the possibility of not harming his performance. ...
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comprising 20 to 30% of the total energy value of the diet [5-7]. And for athletes who need to optimize performance, the carbohydrate recommendation is within the range of 5 to 10 g/ kg-1 body weight/day-1 and in this case the protein can reach the highest range of the recommendation and go up to 4 g/kg-1 body weight/day-1 [8,9]. This way, a strategy refeeding days model was proposed by the author in Table 1, as a strategy that can be used to decrease the body fat percentage of the elite soccer player with the possibility of not harming his performance. References 1. Clemente FM, Ramirez-Campillo R, Sarmento H. Detrimental Effects of the Off-Season in Soccer Players: A Systematic Review and Meta-analysis. Sport Med. 2021;51:795-814. 2. Moura RF, De Moraes WMAM, De Castro BM, et al. Carbohydrate refeed does not modify GVT-performance following energy restriction in bodybuilders. Clin Nutr ESPEN. 2021;43(6):308-316. 3. Antonio Paoli A, Mancin L, Caprio M, et al. Effects of 30 days of ketogenic diet on body composition, muscle strength, muscle area, metabolism, and performance in semi-professional soccer players. Abbreviations CHO: Carbohydrates; PTN: Protein. E ven knowing that elite soccer players body fat mass does not undergo major changes and remains stable and similar across all age groups they ever want to reduce their body fat percentage because, according to their own reports, by doing this they felt light on the pitch. However, during the off-season soccer periods, the elite soccer players tends reduced you performance after training and matches cessation [1], something that could put into question the need for a diet rich in carbohydrates on this moment due increasing body fat percentage fear. However, there is a strategy for prescribing hypocaloric diets commonly used by resistance athletes during reduce body fat percentage phases, which is called refeeding days. Basically, the strategy consists of a calorie-restricted diet during the week and two days during weekends with 100% energy requirements, something that correlates performance maintenance at body fat percentage reduction [2]. And thinking about, it is something that could correlate with elite soccer players reducing caloric intake and training level during soccer off-seasons with diet strategies that can help them maintained sports performance and low body fat percentage during this phase. A study can prove scientifically that hypocaloric diets on low carbohydrate consumption during short periods were able to decrease body fat in elite soccer players without to harm their performance [3]. Thus, it becomes necessary to understand some methodology that leads the athlete to a low-carbohydrate diet, does not make him lose performance over time and maintains his body composition as desired by him. Thus, knowing that the refeeding days strategies can be used implementing one or two days at high carbohydrate and energy intake (generally at or slightly above body weight maintenance levels), thereby providing a break on the another five consecutive days of low carbohydrate and hypocaloric diet [4], this diet model would add as one more strategy to be recommended for soccer players who try to lower the body fat percentage without worse the performance, becomes this proposal for these athletes interesting. Furthermore, dietary prescriptions for athletes who want to reduce body fat percentage remain within the range of less than 45 kcal/kg-1 lean body mass/day-1 , carbohydrates between 3 and 5 g/kg-1 body weight/day-1 , proteins between 1 and 3 g/kg-1 body weight/day-1 and the dietary fat prescription percentage Weekdays Refeeding days (weekend) Dietary intake recommendation CHO: 3 g/kg-1 d-1 PTN: 3g. kg-1 d-1 CHO: 10 g/kg-1 d-1 PTN: 3g/kg-1 d-1
... In terrestrial environments, plants, which are relatively dilute in protein, are much more common than the more protein-rich animals, such that variability in animal prey encounters can result in large individual differences in dietary intake. Many phenotypic traits that directly impact fitness, such as growth [1], immunity [2], body size, aggression [3], strength [4], and locomotor performance [5], vary with dietary protein. Omnivorous animals as diverse as primates and bears, ants and Mormon crickets show variation in these traits in association with diet. ...
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Simple Summary Mormon crickets (Anabrus simplex) are omnivorous, feeding on plants, fungi, and insects, including one another. Because insects contain more protein than plants, prey availability might determine the protein consumed by Mormon crickets. Some grasshoppers co-occur with Mormon crickets and feed on the same hostplants, but little is known about their interactions. We hypothesized that if Mormon crickets feed on grasshoppers, then the Mormon crickets’ needs for alternative protein sources would decline when grasshoppers were more numerous. In addition, because Mormon crickets with less dietary protein had less immunity, we hypothesized that greater grasshopper density would enhance Mormon cricket immunity. In a field setting, we varied the numbers of Mormon crickets from 0 to 20 and the numbers of grasshoppers Melanoplus borealis from 0 to 45 m⁻² in 68 1-m² cages. After one month, we measured Mormon cricket dietary preferences and immune activity. As predicted, we found that protein consumption from the alternative source declined as grasshopper density increased, and immunocompetence increased with grasshopper availability. In addition, plant nitrogen declined with increasing insect density, reinforcing the importance of predation by Mormon crickets to meet their protein needs. Potentially influencing management decisions, Mormon crickets affect grasshopper populations, and grasshopper abundance might be an indicator of Mormon cricket immunity. Abstract In addition to feeding on plants, Mormon crickets Anabrus simplex Haldeman, 1852 predate on invertebrates, including one another, which effectively drives their migration. Carnivory derives from lack of dietary protein, with Mormon crickets deprived of protein having less phenoloxidase (PO) available to combat foreign invaders, such as fungal pathogens. Because Mormon crickets commonly occur with grasshoppers that feed on the same plants, we investigated interactions between grasshoppers and Mormon crickets, and hypothesized that if Mormon crickets are predatory on grasshoppers, grasshopper abundance would influence the protein available to Mormon crickets and their immunity. In a field setting, we varied densities of Mormon crickets (0, 10, or 20 per cage) and grasshoppers Melanoplus borealis (0, 15, 30, or 45) in 68 1-m² cages. After one month, we measured Mormon cricket dietary preferences and PO activity. As predicted, artificial diet consumption shifted away from protein as grasshopper density increased, and immunocompetence, as measured by PO activity, also increased with grasshopper availability. Although nitrogen availability in the vegetation decreased with increasing insect density, predation became an important source of protein for Mormon crickets that enhanced immunity. Grasshoppers can be an important source of dietary protein for Mormon crickets, with prey availability affecting Mormon cricket immunity to diseases.
... Administration of a preexercise supplement was based on a previous protocol published by Shaw et al. (2017). Administration of supplements immediate postexercise was based on the prevailing recommendations with regard to protein supplementation after exercise (Phillips & van Loon, 2011). All supplements were dissolved in 300 ml of water. ...
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Previous studies showed that collagen peptide supplementation along with resistance exercise enhance muscular recovery and function. Yet, the efficacy of collagen peptide supplementation in addition to standard nutritional practices in athletes remains unclear. Therefore, the objective of the study was to compare the effects of combined collagen peptide (20 g) and whey protein (25 g) supplementation with a similar daily protein dose (45 g) of whey protein alone on indices of muscle damage and recovery of muscular performance during eccentric exercise training. Young fit males participated in a 3-week training period involving unilateral eccentric exercises for the knee extensors. According to a double-blind, randomized, parallel-group design, before and after training, they received either whey protein ( n = 11) or whey protein + collagen peptides ( n = 11). Forty-eight hours after the first training session, maximal voluntary isometric and dynamic contraction of the knee extensors were transiently impaired by ∼10% ( P time < .001) in whey protein and whey protein + collagen peptides, while creatine kinase levels were doubled in both groups ( P time < .01). Furthermore, the training intervention improved countermovement jump performance and maximal voluntary dynamic contraction by respectively 8% and 10% ( P time < .01) and increased serum procollagen type 1N-terminal peptide concentration by 10% ( P time < .01). However, no differences were found for any of the outcomes between whey and whey protein + collagen peptides. In conclusion, substituting a portion of whey protein for collagen peptide, within a similar total protein dose, improved neither indices of eccentric muscle damage nor functional outcomes during eccentric training.
... La calidad nutricional de las proteínas vegetales puede ser inferior en algunos aspectos en comparación con las proteínas animales, lo que podría tener un impacto en la masa y fuerza muscular de los deportistas. Existe un rango de consumo de proteína que garantiza la síntesis de proteica muscular (1,3-1,8 gr/Kg/día) [Phillips & Van Loon, 2011], independiente del origen de la proteína. Los ejercicios de fuerza son generalmente acciones de alta intensidad, pero de corta duración, por lo que la calidad de la proteína es un factor preponderante en los deportes con sobrecarga. ...
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La evidencia científica sobre el consumo de dietas vegetarianas en el rendimiento deportivo, ha experimentado un notable incremento en los últimos tiempos. Existen diversas razones por las cuales las dietas basadas en plantas han ganado popularidad entre los deportistas. Entre estas razones, destaca el hecho de que los alimentos de origen animal pueden tener efectos nocivos en la salud debido a su mayor contenido de grasas saturadas aumentando el riesgo de generar patologías gastrointestinales, obesidad y enfermedad en el sistema nervioso central (Cai et al., 2022). Por otro lado, una dieta rica en frutas, verduras y legumbres puede ejercer efectos antiinflamatorios y antioxidantes, generando así un impacto positivo en el rendimiento deportivo y mejora en los tiempos de recuperación post ejercicio de fuerza (Naclerio PhD et al., 2021). Además, el enfoque ético hacia los animales también juega un papel importante en esta tendencia hacia las dietas vegetarianas (Hertzler et al., 2020). Estas se pueden clasificar en ocho tipos diferentes: i) Omnívora, ii) semivegetariana, iii) Lacto-vegetariana, iv) Ovo-vegetariana, v) pesco-vegetariana, vi) Ovo-lacto-vegetariana, vii) Pesco-lacto-ovo-vegetariana, viii) vegana (Pohl et al., 2021).
... When the body is in a low-hydration state (or dehydration), the water content in the blood decreases, the solute concentration increases, the blood viscosity increases, the fluidity decreases, and the blood circulation is blocked; when the body is in a high-hydration state (or overhydration), the water content in the blood increases, the solute concentration decreases, the blood viscosity decreases, the fluidity increases, and the blood circulation is too fast. These changes will affect the delivery efficiency of nutrients and hormones in the blood, which include oxygen, glucose, amino acids, insulin, growth hormone, etc., which are essential factors for supporting muscle metabolism and synthesis [69,70]. When the delivery efficiency of nutrients and hormones in the blood is low, it will cause muscle cells to lack oxygen, glucose, amino acids, insulin, growth hormone, and other factors, thus affecting the metabolism and synthesis of muscle cells, reducing the energy production and protein increase in muscle cells. ...
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This study aimed to examine the relationship between daily total intake of water (DTIW) and handgrip strength (HGS) among US adults and to explore the impact of water intake on muscle function and health, providing a reference for public health policies and health education. Using the data from the National Health and Nutrition Examination Survey (NHANES) 2011–2014, a cross-sectional survey design was adopted to analyze 5427 adults (48.37% female and 51.63% male) aged 20 years and above. DTIW was assessed using two non-consecutive 24 h dietary recall interviews, and the HGS level was measured using a Takei Dynamometer. Weighted generalized linear regression models and restricted cubic spline plots were used to analyze the linear and nonlinear associations between DTIW and HGS level and to conduct a gender subgroup analysis and an interaction effect test. The results showed that there were significant differences in HGS and other characteristics among different quartile groups of DTIW (p < 0.05). There was a significant nonlinear trend (exhibiting an inverted U-curve) between DTIW and HGS (p for nonlinear = 0.0044), with a cut-off point of 2663 g/day. Gender subgroup analysis showed that the nonlinear trend (exhibiting an inverted U-curve) was significant only in males (p for nonlinear = 0.0016), with a cut-off point of 2595 g/day. None of the stratified variables had an interaction effect on the association between DTIW and HGS (p for interaction > 0.05). In conclusion, this study found a nonlinear association between DTIW and HGS levels, as well as a gender difference. This finding provides new clues and directions for exploring the mechanism of the impact of DTIW on muscle function and health and also provides new evidence and suggestions for adults to adjust their water intake reasonably.
... La calidad nutricional de las proteínas vegetales puede ser inferior en algunos aspectos en comparación con las proteínas animales, lo que podría tener un impacto en la masa y fuerza muscular de los deportistas. Existe un rango de consumo de proteína que garantiza la síntesis de proteica muscular (1,3-1,8 gr/Kg/día) [Phillips & Van Loon, 2011], independiente del origen de la proteína. Los ejercicios de fuerza son generalmente acciones de alta intensidad, pero de corta duración, por lo que la calidad de la proteína es un factor preponderante en los deportes con sobrecarga. ...
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Esta carta al edito informa que la proteina vegetal es una opción válida para el aumento de la fuerza y masa muscular en deportistas.
... This might have contributed to weight loss and LBM reduction in our study than theirs. In addition, a more significant percentage of IMTC in this study was endurance/aerobic training than resistance training, which may further explain the LBM decline [24,25]. ...
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Background In preparation for military service, new recruits undergo a physical transformation. We aimed to determine the fitness outcomes and self-reported activity levels of Saudi medical recruits after a 10-week initial military training course (IMTC). Methods The cohort comprised 104 recruits aged 25-29 years. Anthropometric variables, including height, body mass index (BMI), body weight (BW), percent body fat (%BF), lean body mass (LBM), waist circumference (WC), and waist-to-height ratio (WtHR), were assessed pre-IMTC and post-IMTC. Physical fitness assessments, including a one-minute sit-up test, push-up test, Cooper's 12-minute run/walk test, and relative maximal oxygen consumption (VO2 max), were also evaluated. The International Physical Activity Questionnaire (IPAQ) was used to assess self-reported physical activity. Results We found a significant decrease in anthropometric variables following the course, including BW (P = 0.01), BMI (P = 0.01), %BF (P = 0.002), LBM (P = 0.01), WC (P = 0.005), and WtHR (P = 0.003). They also showed significant improvements in the push-up test (P = 0.001), one-minute sit-up test (P = 0.001), 12-minute test (P = 0.001), and relative VO2 max (P = 0.001). The comparison of pre-IPAQ with post-IPAQ demonstrated a percentage improvement in walking activity (15%-82%) and vigorous physical activity (17%-49%) after joining the IMTC. Conclusions These findings demonstrate that Saudi medical recruits who partake in the IMTC can attain significant improvements in their body composition, physical fitness, and physical activity levels.
... This was consistent with a previous report that athletic individuals consume larger amounts of dietary protein than nonathletes because of the energy required for physical activity. 125 The current finding of a significant decrease in water intake among athletic and physically active participants during RF is supported by previous studies reporting decreased fluid intake 91,126 or a negative fluid balance 127,128 among athletes. The decreased water intake could be explained by changes in meal timing and frequency during RF (food/water only consumed during the nighttime), which may affect total fluid and water intake. ...
Article
Context Ramadan fasting (RF) is associated with various physiological and metabolic changes among fasting Muslims. However, it remains unclear whether these effects are attributable to changes in meal timing or changes in dietary energy and macronutrient intakes. Furthermore, the literature on the associations between RF, meal timing, and energy and macronutrient intakes is inconclusive. Objectives This systematic review aimed to estimate the effect sizes of RF on energy and macronutrient intakes (carbohydrates, protein, fats, dietary fiber, and water) and determine the effect of different moderators on the examined outcomes. Data Sources The Cochrane, CINAHL, EMBASE, EBSCOhost, Google Scholar, PubMed/MEDLINE, ProQuest Medical, Scopus, ScienceDirect, and Web of Science databases were searched from inception to January 31, 2022. Data Extraction The studies that assessed energy, carbohydrate, protein, fat, fiber, and water intakes pre- and post-fasting were extracted. Data Analysis Of the 4776 identified studies, 85 relevant studies (n = 4594 participants aged 9–85 y) were selected. The effect sizes for the studied variables were as follows: energy (number of studies [K] = 80, n = 3343 participants; mean difference [MD]: −142.45; 95% confidence interval [CI]: −215.19, −69.71), carbohydrates (K = 75, n = 3111; MD: −23.90; 95% CI: −36.42, −11.38), protein (K = 74, n = 3108; MD: −4.21; 95% CI: −7.34, −1.07), fats (K = 73, n = 3058; MD: −2.03; 95% CI: −5.73, 1.67), fiber (K = 16, n = 1198; MD: 0.47; 95% CI: −1.44, 2.39), and water (K = 17, n = 772; MD: −350.80; 95% CI: −618.09, 83.50). Subgroup analyses showed age significantly moderated the 6 dietary outcomes, and physical activity significantly moderated water intake. There were significant reductions in energy, carbohydrate, and protein intakes during RF. Conclusions The change in meal timing rather than quantitative dietary intake may explain various physiological and health effects associated with RF.
... This suggests that, on average, the individual engages in this practice less frequently than others. Adequate protein intake is crucial for athletes as it plays a vital role in muscle recovery and adaptation [14] . Therefore, the individual's adherence to this practice is commendable. ...
... Additionally, protein consumption is often a primary concern for those adopting a vegan or vegetarian diet [11]. Many focus on quantity of protein consumption, with many recommending at least 1.2-1.7 g/kg body weight per day (1.2-1.4 g/kg/day recommended for endurance athletes and 1.6-1.7 g/kg/day for strength and power athletes); however, this is not taking protein quality into account [81][82][83][84]. Despite the fact that soy can be high in protein and appears in the bloodstream quickly, even with similar quantities, there is conflicting evidence on the quality of soy protein. ...
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Background: Nutrition fuels optimal performance for athletes. With increased research developments, numerous diets available, and publicity from professional athletes, a review of dietary patterns impact on athletic performance is warranted. Results: The Mediterranean diet is a low inflammatory diet linked to improved power and muscle endurance and body composition. Ketogenic diets are restrictive of carbohydrates and proteins. Though both show no decrements in weight loss, ketogenic diets, which is a more restrictive form of low-carbohydrate diets, can be more difficult to follow. High-protein and protein-paced versions of low-carbohydrate diets have also shown to benefit athletic performance. Plant-based diets have many variations. Vegans are at risk of micronutrient deficiencies and decreased leucine content, and therefore, decreased muscle protein synthesis. However, the literature has not shown decreases in performance compared to omnivores. Intermittent fasting has many different versions, which may not suit those with comorbidities or specific needs as well as lead to decreases in sprint speed and worsening time to exhaustion. Conclusions: This paper critically evaluates the research on diets in relation to athletic performance and details some of the potential risks that should be monitored. No one diet is universally recommend for athletes; however, this article provides the information for athletes to analyze, in conjunction with medical professional counsel, their own diet and consider sustainable changes that can help achieve performance and body habitus goals.
... Mean (± standard deviation) daily macronutrient intakes compared to current sports nutrition recommendations (Thomas et al.[15] and Phillips and Van Loon[31]). Mean calcium, iodine, and vitamins A and E in TRAIN were higher than nutrition recommendations (Calcium TRAIN : 1047 ± 323 mg, +40%, p = 0.003, d = 1.59; Iodine TRAIN : 205 ± 83 mg, +38%, p = 0.02, d = 1.16; ...
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To understand the energy balance of international female rugby sevens (R7s) players in applied environments, this study estimated the energy intakes (EI) and total daily estimated energy expenditures (TDEE) during a five-day training camp (TRAIN) and phase of competition preparation (COMP) of equal duration. Tri-axial accelerometer devices were worn throughout both scenarios to estimate TDEE, whereas EI was estimated via self-reported food diaries. Energy deficits of −47% (TDEE TRAIN : 14.6 ± 1.6 MJ·day −1 , EI TRAIN : 7.7 ± 0.9 MJ·day −1 , p ≤ 0.001, d = 5.1) and −50% (TDEE COMP : 15.5 ± 1.6 MJ·day −1 , EI COMP : 7.7 ± 1.0 MJ·day −1 , p ≤ 0.001, d = 5.7) were observed throughout TRAIN (n = 11; age: 25 ± 4 years, height: 170 ± 6 cm, weight: 71 ± 7 kg) and COMP (n = 8; age: 25 ± 3 years, height: 172 ± 5 cm, weight: 72 ± 6 kg), respectively. Carbohydrate intakes were below the lower range of sports nutrition recommendations in both TRAIN (−62%; 2.3 ± 0.3 g·kg −1 BM, p ≤ 0.001) and COMP (−60%; 2.4 ± 0.5 g·kg −1 BM, p ≤ 0.001). For protein (TRAIN: 1.7 ± 0.4 g·kg −1 BM, COMP: 1.5 ± 0.1 g·kg −1 BM), intakes met the lower range of recommendations. Fat intake exceeded recommendations of the percentage of total EI (COMP: 39 ± 5%). Accordingly, the dietary strategies of international female R7s players may warrant optimization, as carbohydrate and fat intakes were less than optimal when compared to current performance-based sports nutrition guidelines.
... Protein intake is essential for the metabolic adaptation process and the recovery of damaged muscular fibers; however, it is only recommended in larger quantities for short periods during intensive training or when total energy and carbohydrate intake is reduced (Mettler et al., 2010). Furthermore, there is evidence to suggest that protein intake during exercise may have an ergogenic effect by delaying the runnersé xhaustion (Phillips & Van Loon, 2011). ...
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GARCÍA-DÁVILA, M. Z.; RAMÍREZ-SIQUEIROS, M. G.; BAUER, P.; MAKIVIC, B.; HERNÁNDEZ-CRUZ, G.; RANGEL-COLMENERO, B. R.; VALENCIA-FALCÓN, T.; YÁÑEZ-SEPÚLVEDA, R. & MARTÍNEZ-RODRÍGUEZ, A. Analysis of dietary intake and body composition of collegiate runners. Int. J. Morphol., 41(3):845-850, 2023. SUMMARY: The aim of this cross-sectional study was to compare dietary intake to published recommendations and to analyze the potential relationship between body composition and dietary intake in collegiate athletes. Eighteen healthy male middle-and long-distance runners (age 20.11 ± 2.72 y; height, 174.7 ± 6.1 cm; body mass, 64.0 ± 7.7 kg), were recruited from a Mexican university track and field team at the beginning of the general preparation phase for national competitions. Participants completed three 24-hour dietary recalls, which were used to estimate dietary intake. Body composition was measured by Dual-energy X-ray absorptiometry (DXA). Athletes displayed high body fat values. Protein intake was significantly higher than published recommendations. Iron, zinc, sodium, and vitamin C intake were significantly higher than recommended values, while potassium and calcium intake were below established recommendations. No significant correlations between body composition variables (i.e body fat, lean body mass, bone mineral content) and dietary intake (i.e energy, macronutrients and selected vitamins and minerals) could be found. These findings suggest that coaches and practitioners should pay close attention to dietary intake and body composition of endurance athletes starting general preparation for competition. Future studies on changes of dietary intake and body composition during off-season and competitive phase, which also track physical activity, are warranted.
... In addition, adequate CHO intake is important to minimize the risk of illness [31] and overtraining [32]. Protein, in turn, plays an essential role as a substrate for recovery and trigger for adaptation after exercise [33], thus adequate amount of protein is needed for recovery and training adaptation. Given that high load endurance training [34], whole body training [35], adolescence [36], energy deficiency [37] and low CHO availability [38] may increase protein requirements, a protein intake in the upper range or slightly above current recommendations [12] may have been beneficial for the participants in the present study. ...
Article
Background: Low energy availability (LEA) can have negative performance consequences, but the relationships between LEA and performance are poorly understood especially in field conditions. In addition, little is known about the contribution of macronutrients to long-term performance. Therefore, the aim of this study was to evaluate if energy availability (EA) and macronutrient intake in a field-based situation were associated with laboratory-measured performance, anthropometric characteristics, blood markers, training volume, and/or questionnaire-assessed risk of LEA in young female cross-country (XC) skiers. In addition, the study aimed to clarify which factors explained performance. Methods: During a one-year observational study, 23 highly trained female XC skiers and biathletes (age 17.1 ± 1.0 years) completed 3-day food and training logs on four occasions (September-October, February-March, April-May, July-August). Mean (±SD) EA and macronutrient intake from these 12 days were calculated to describe yearly overall practices. Laboratory measurements (body composition with bioimpedance, blood hormone concentrations, maximal oxygen uptake (VO2max), oxygen uptake (VO2) at 4 mmol·L-1 lactate threshold (OBLA), double poling (DP) performance (time to exhaustion), counter movement jump (height) and the Low Energy Availability in Females Questionnaire (LEAF-Q)) were completed at the beginning (August 2020, M1) and end of the study (August 2021, M2). Annual training volume between measurements was recorded using an online training diary. Results: The 12-day mean EA (37.4 ± 9.1 kcal·kg FFM-1·d-1) and carbohydrate (CHO) intake (4.8 ± 0.8 g·kg-1·d-1) were suboptimal while intake of protein (1.8 ± 0.3 g·kg-1·d-1) and fat (31 ± 4 E%) were within recommended ranges. Lower EA and CHO intake were associated with a higher LEAF-Q score (r = 0.44, p = 0.042; r = 0.47, p = 0.026). Higher CHO and protein intake were associated with higher VO2max (r = 0.61, p = 0.005; r = 0.54, p = 0.014), VO2 at OBLA (r = 0.63, p = 0.003; r = 0.62, p = 0.003), and DP performance at M2 (r = 0.42, p = 0.051; r = 0.44, p = 0.039). Body fat percentage (F%) was negatively associated with CHO and protein intake (r = -0.50, p = 0.017; r = -0.66, p = 0.001). Better DP performance at M2 was explained by higher training volume (R2 = 0.24, p = 0.033) and higher relative VO2max and VO2 at OBLA at M2 by lower F% (R2 = 0.44, p = 0.004; R2 = 0.47, p = 0.003). Increase from M1 to M2 in DP performance was explained by a decrease in F% (R2 = 0.25, p = 0.029). Conclusions: F%, and training volume were the most important factors explaining performance in young female XC skiers. Notably, lower F% was associated with higher macronutrient intake, suggesting that restricting nutritional intake may not be a good strategy to modify body composition in young female athletes. In addition, lower overall CHO intake and EA increased risk of LEA determined by LEAF-Q. These findings highlight the importance of adequate nutritional intake to support performance and overall health.
... Given that natural athletes abstain from these compounds, some coaches may consider decreasing absolute protein amounts to create the deficit required to achieve stage leanness. However, this reduction should be modest as several groups of authors have postulated that higher protein intakes during energy restriction may help reduce the loss of lean body mass in resistance-trained athletes [10][11][12]. ...
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Bodybuilding is a sport where coaches commonly recommend a variety of nutrition and exercise protocols, supplements, and, sometimes, performance-enhancing drugs (PEDs). The present study sought to gain an understanding of the common decisions and rationales employed by bodybuilding coaches. Focusing on coaches of the more muscular divisions in the National Physique Committee/IFBB Professional League federations (men’s classic physique, men’s bodybuilding, women’s physique, women’s bodybuilding) for both natural and enhanced athletes, coaches were recruited via word of mouth and social media, and 33 responded to an anonymous online survey. Survey responses indicated that participant coaches recommend three-to-seven meals per day and no less than 2 g/kg/day of protein regardless of sex, division, or PED usage. During contest preparation, participant coaches alter a natural competitor’s protein intake by −25% to +10% and an enhanced competitor’s protein intake by 0% to +25%. Regarding cardiovascular exercise protocols, approximately two-thirds of participant coaches recommend fasted cardiovascular exercise, with the common rationale of combining the exercise with thermogenic supplements while considering the athlete’s preference. Low- and moderate-intensity steady state were the most commonly recommended types of cardiovascular exercise among participant coaches; high-intensity interval training was the least popular. Creatine was ranked in the top two supplements for all surveyed categories. Regarding PEDs, testosterone, growth hormone, and methenolone were consistently ranked in the top five recommended PEDs by participant coaches. The results of this study provide insight into common themes in the decisions made by bodybuilding coaches, and highlight areas in which more research is needed to empirically support those decisions.
... However, there is evidence that athletes competing in team sports, including volleyball, do not follow dietary recommendations [10][11][12]. Additionally, female athletes, although seeming to consume more protein and fats, have a total energy intake less than that of male athletes [5,13,14]. Moreover, the appropriate consumption of some nutritional supplements may enhance sports performance [15]. ...
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Evidence suggests that athletes competing in team sports do not follow dietary recommendations. However, only few studies have investigated energy needs and supplement use in adolescent athletes, and whether they are meeting their energy requirements. This observational study examined energy expenditure, dietary energy intake, and use of nutritional supplements in 58 adolescent (14–17 years old) volleyball athletes (15 males, 43 females) and 58 age-matched nonathletic controls (13 males, 45 females). Participants completed an online survey including questions on demographic information, body mass, and a series of standardized questionnaires assessing energy expenditure, dietary energy, macronutrient, micronutrient, and supplement intake. Energy expenditure relative to body mass was higher in athletes than nonathletes by 13 kcal/kg/day (group effect, p < 0.001), and in males compared to females by 5.7 kcal/kg/day (sex effect, p = 0.004). Athletes had higher energy intake than nonathletes (+6.4 kcal/kg/day, p = 0.019) and greater consumption of fruits (p = 0.034), vegetables (p = 0.047), grains (p = 0.016), dairy (p = 0.038), meats and meat alternatives (p < 0.001), as well as higher intakes of fat (p < 0.001), carbohydrates, protein, sugar, fiber, vitamin C, calcium, and sodium (p = 0.05) compared to nonathletes. The average protein intakes exceeded the upper recommendations in all groups, suggesting that this is not a nutrient of concern for young volleyball athletes. However, athletes were only meeting 60% of the estimated energy requirements (EER) for their age, height, body mass, and physical activity score, (3322 ± 520 kcal/day), while nonathletes were meeting 74% of the EER (p < 0.001). The relative energy balance of male athletes was lower compared to both female athletes (p = 0.006) and male nonathletes (p = 0.004). Finally, more athletes reported using performance-related supplements than nonathletes, but there were no differences in the consumption of other dietary supplements. Overall, when compared to nonathletic controls, both male and female adolescent volleyball athletes were found to match their higher energy expenditure with a greater dietary energy intake; however, all adolescents were below the estimated energy requirements, a finding more profound among the volleyball athletes.
... Soccer is a predominantly aerobic sport that also includes frequent bouts of explosive activity, such as short sprints, tackles, duel play, and jumps, which depend on anaerobic energy production [1,2]. As soccer training elicits substantial musculoskeletal stress, disruption, and damage, dietary protein is needed to support recovery and adaptation [1,[3][4][5][6]. Moreover, dietary protein is a key variable for lean body mass (LBM) accrual, which in turn can confer performance benefits to the soccer player by improving strength and power output [3,7]. ...
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Dietary protein is required to support recovery and adaptation following exercise training. While prior research demonstrates that many athletes meet total daily protein needs, intake seems to be predominantly skewed toward the evening meal. An even distribution of protein doses of ≥0.24 g/kg BW consumed throughout the course of a day is theorized to confer greater skeletal muscle anabolism outcomes compared to a skewed pattern of intake. Protein quality is also an important dietary consideration for athletes, with the amino acid leucine seemingly serving as the primary driver of the postprandial anabolic response. The present study investigates protein consumption characteristics among a cohort of NCAA D1 soccer players and evaluates differences between male and female athletes. Athletes were instructed to complete 3-day food diaries, which were subsequently analyzed and compared to UEFA expert group-issued nutrition guidelines for soccer players. Breakfast, lunch, and dinner accounted for 81.4% of the total daily dietary protein intake. Most athletes (77.8%) ingested optimum amounts of protein at dinner but not at breakfast (11.1%) or lunch (47.2%). In addition, statistically significant sex-based differences in daily dietary protein intake, meal-specific protein amounts, and protein quality measures were detected. Findings indicate suboptimal dietary protein intake practices among the collegiate soccer athletes.
... Considering that a diet with more than 2.0 g of protein per kilogram of body weight per day did not protect lean body mass loss during energy deficits at a high altitude [78], and that protein intakes in the range of 1.3-1.8 g per Kg per day distributed along the day in frequent meals maximise the protein synthesis at sea level [79], recommendations for protein ingestion at altitude should be made considering the ingestion of high quality protein as such to reach a minimum 1.3 g per Kg per day as long as it does not impair carbohydrate ingestion, with a careful timing distribution and prioritising key branchedchain amino acids such as leucine, which can act either as a substrate and as a regulator of protein synthesis [80]. ...
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This report aims to summarise the scientific knowledge around hydration, nutrition, and metabolism at high altitudes and to transfer it into the practical context of extreme altitude alpinism, which, as far as we know, has never been considered before in the literature. Maintaining energy balance during alpine expeditions is difficult for several reasons and requires a deep understanding of human physiology and the biological basis for altitude acclimation. However, in these harsh conditions it is difficult to reconcile our current scientific knowledge in sports nutrition or even for mountaineering to high-altitude alpinism: extreme hypoxia, cold, and the logistical difficulties intrinsic to these kinds of expeditions are not considered in the current literature. Requirements for the different stages of an expedition vary dramatically with increasing altitude, so recommendations must differentiate whether the alpinist is at base camp, at high-altitude camps, or attempting the summit. This paper highlights nutritional recommendations regarding prioritising carbohydrates as a source of energy and trying to maintain a protein balance with a practical contextualisation in the extreme altitude environment in the different stages of an alpine expedition. More research is needed regarding specific macro and micronutrient requirements as well as the adequacy of nutritional supplementations at high altitudes.
... Protein is an essential macronutrient for immune function, tissue growth, maintenance, and repair (Rodriguez, 2013). In addition, adequate protein intake is also important for preserving lean mass if an athlete has low AD, is recovering from injury, or during short periods of intense training (Phillips & Van Loon, 2011). ...
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Although Volleyball is one of the most widely played sports in the World, there is little scientific information on how the ergo nutritional practice of female players should be designed. Therefore, the main aim of this narrative review is to resolute concise nutritional recommendations for volleyball women who players. Research databases such as PubMed, Scielo, Scopus, Medline or Academic Search Complete summarize and synthesize the recent evidence on the role of nutrition and its relationship with health and performance in this sporting discipline. Based on a literature review, we highlight that the individual adjustment of the energy value of the diet is one of the key factors for the physical performance of female volleyball players. An adequate intake of macronutrients allows for the achievement of correct energy values. To improve training adaptation, between 1.6 and 2.2 g·(kg·day)-1 of protein should be consumed. For optimal pre-competition muscle glycogen storage, 6-10 g·(kg·day)-1 of carbohydrates should be consumed, and 7-10 g·(kg·day)-1 of carbohydrates should be consumed for adequate recovery. Micronutrients should be consumed in amounts corresponding to the recommended dietary allowances. Women volleyball players should take particular attention to the most adequate intake of these micronutrients, as well as vitamins such as iron, calcium, and vitamin D. Proper fluid intake, according to the player's needs, is crucial to maximize exercise performance. The diet of a female athlete is often characterized by low energy values, which increases the risk of various health consequences related to low energy availability. This diet of volleyball players must therefore be controlled carefully.
... increases in muscle mass and strength) up to a total daily protein intake of 1.6 g/kg, beyond which no further benefits are observed [1]. Thus, although protein requirements in endurance athletes seem to be increased, particularly during periods of strenuous training loads such as those applied here [45,57], the amount of proteins present in the normal diet of our participants might have sufficed to meet physiological demands. ...
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Background: The effects of pre-sleep protein supplementation on endurance athletes remain unclear, particularly whether its poten- tial benefits are due to the timing of protein intake or solely to an increased total protein intake. We assessed the effects of pre-sleep protein supplementation in professional cyclists during a training camp accounting for the influence of protein timing. Methods: Twenty-four professional U23 cyclists (19 ± 1 years, peak oxygen uptake: 79.8 ± 4.9 ml/kg/min) participated in a six-day training camp. Participants were randomized to consume a protein supplement (40 g of casein) before sleep (n = 8) or in the afternoon (n = 8), or an isoenergetic placebo (40 g of carbohy- drates) before sleep (n = 8). Indicators of fatigue/recovery (Hooper index, Recovery–Stress Questionnaire for Athletes, countermove- ment jump), body composition, and performance (1-, 5-, and 20- minute time trials, as well as the estimated critical power) were assessed as study outcomes. Results: The training camp resulted in a significant (p < 0.001) increase in training loads (e.g. training stress score of 659 ± 122 per week during the preceding month versus 1207 ± 122 during the training camp), which induced an increase in fatigue indicators (e.g. time effect for Hooper index p < 0.001) and a decrease in performance (e.g. time effect for critical power p = 0.002). Protein intake was very high in all the participants (>2.5 g/kg on average), with significantly higher levels found in the two protein supplement groups compared to the placebo group (p < 0.001). No significant between-group differences were found for any of the analyzed outcomes (all p > 0.05). Conclusions: Protein supplementation, whether administered before sleep or earlier in the day, exerts no beneficial effects during a short-term strenuous training period in professional cyclists, who naturally consume a high-protein diet.
... This negative balance results in muscle wasting which is detrimental to exercise performance, and often also elevates injury risk (Fogelholm, 1994). A strategy to circumvent this problem is to increase the daily intake of high-quality protein (for a review on dietary protein, see (Phillips and Van Loon, 2011)). Indeed, a high-protein diet in young, physically active volunteers effectively prevented muscle atrophy during shortterm caloric restriction (Mettler et al., 2010;Pasiakos et al., 2013;Longland et al., 2016). ...
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... w/v/w) in d.H O is a functional beverage that provides the body with a high-quality protein and a considerable amount of antioxidants. KEYWORDS whey proteins, beetroot peels, antioxidant activity, proteins, functional beverages, betalains, bioactive components Introduction Sufficient protein intake is vital for everyone (athletes and sedentary persons): Proteins increase the protein muscle synthesis, compensate for the amino acid loss (∼50-60 g/70-90 kg) between the proteins synthesis and breaking down (1), and elevate the satiety feeling (2). Whey, the by-product of cheese manufacturing (3)(4)(5), is produced in significant amounts 10 liters/ kg cheese. ...
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Introduction Adequate protein and antioxidant intake are crucial for everyone, particularly athletes, to promote muscle performance and prevent muscle damage. Whey proteins are high-quality proteins with high digestibility and bioavailability; beetroot peels are an abundant antioxidant source. Methods The present study was designated to develop a functional beverage based on mixing whey protein isolate (5%) with different concentrations of beetroot peel water extract (1, 2.5, and 5%) and flavored with strawberries puree (5%). In addition, we examined the stability of the physicochemical parameters and the bioactive components of the beverages during cold storage (4°C) for 14 days. Results and discussion Whey protein isolates enriched the juices with stable protein content during the storage (4.65–4.69%). Besides, the extract revealed a concentration-dependent effect on the bioactive components, the antioxidant activity, and the microbial load of the juices; it distinguished the fresh juices by high betalains and nitrate content, 87.31–106.44 mg/L and 94.29–112.59 mg/L, respectively. Beverages with 2.5% peel extract (T2) had the preferable sensory attributes compared to control and other treatments. On day 0, phenolics and flavonoids increased in T2 by 44 and 31% compared to the control, which elevated the scavenging activity of the juice (T2) ( P < 0.05). At the end of the storage period (14 days), phenolics and flavonoids of T2 recorded their lowest values, 26.23 and 21.75 mg/mL, respectively. However, they stood higher than phenolics (22.21 mg/mL) ( p < 0.05) and flavonoids (18.36 mg/mL) ( p > 0.05) of control. Similarly, betalains degraded by 45% to reach 47.46 mg/L in T2, which reduced the redness (a * ) and increased the yellowness (b * ) values. Conclusion Consequently, whey/strawberry/beetroot peel (5: 5: 2.5 w/v/w) in d.H 2 O is a functional beverage that provides the body with a high-quality protein and a considerable amount of antioxidants.
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Diet can be considered as one of the pivotal factors in regulating gastrointestinal health, and polyphenols widely distributed in human daily diet. The polyphenols and their metabolites playing a series of beneficial effects in human gastrointestinal tract that can regulate of the gut microbiota, increase intestinal barrier function, repair gastrointestinal mucosa, reduce oxidative stress, inhibit the secretion of inflammatory factors and regulating immune function, and their absorption and biotransformation mainly depend on the activity of intestinal microflora. However, little is known about the two-way interaction between polyphenols and intestinal microbiota. The objective of this review is to highlight the structure optimization and effect of flavonoids on intestinal flora, and discusses the mechanisms of dietary flavonoids regulating intestinal flora. The multiple effects of single molecule of flavonoids, and inter-dependence between the gut microbiota and polyphenol metabolites. Moreover, the protective effects of polyphenols on intestinal barrier function, and effects of interaction between plant polyphenols and macromolecules on gastrointestinal health. This review provided valuable insight that may be useful for better understanding the mechanism of the gastrointestinal health effects of polyphenols, and provide a scientific basis for their application as functional food.
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ÖZET Kuersetin ve Resveratrol Tüketiminin Elit Adölesan Atletizm Mesafe Koşucularının Laktik Asit Düzeyleri ile Koşu Performansı Üzerine Etkilerinin İncelenmesi Bu çalışmanın amacı kuersetin ve resveratrol tüketiminin elit adölesan atletizm mesafe koşucularının laktik asit düzeyleri ile koşu performansı üzerine etkilerinin incelenmesidir. Araştırmaya Isparta ilinde bulunan elit düzeyde atletizm ile ilgilenen 4 kadın ve 4 erkek adölesan sporcu katılmıştır. Çalışmaya katılan elit adölesan atletlerin yaş ortalamaları 16,13±2,03 yıl, sporcuların vücut ağırlığı ortalamaları 52,02±6,91 kg, boy ortalamaları ise 168,3±10,61 cm olarak tespit edilmiştir. Adölesan sporcuların performanslarına kuersetin ve resveratrolün etkisini ölçmek için çalışma birer hafta ara ile 3 hafta sürmüştür. Her haftanın belirlenen 2 günü kampa alınarak ilk hafta plasebo, ikinci hafta 500 mg kuersetin ve üçüncü hafta 100 mg resveratrol takviyeleri verilmiştir. Kampın ilk günü takviyesiz 1500 m koşmaları istenmiştir. Koşu öncesi ve sonrası laktik asit ölçümü alınmış ve koşu süreleri kaydedilmiştir. İkinci günü ise takviyeler verilerek aynı ölçümler tekrarlanmıştır. Araştırmada; lactate scout, kronometre ve bioelektrik direnç ölçüm cihazı kullanılmıştır. Elde edilen verilerin analizi için Paired – T Testi ve Korelasyon Testlerinden faydalanılmıştır, anlamlılık düzeyi 0,05 olarak kabul edilmiştir. Elde edilen bulgulara bakıldığında; Kuersetin takviyesinin akut etkisinin kadın sporcularda biriken laktik asit seviyelerinde anlamlı düzeyde olduğu, erkeklerde ise koşu süresinde fark oluşturmasına rağmen istatistiksel olarak anlamlı olmadığı, resveratrol takviyesinde ise akut etkinin olmadığı dolayısıyla anlamlı bir sonuç çıkmadığı tespit edilmiştir. Sonuç olarak; kuersetin ve resveratrol müdahalelerinde yalnızca kuersetin takviyesinin kadın elit adölesan atletlerde istatistiksel olarak anlamlı fark yarattığı görülmüştür. Fakat istatistiksel olarak anlamlı çıkmasa da Atletizm spor dalı için çok önemli olan koşu süresi farklılıkları ile karşılaşılmıştır. Dolayısıyla bu çalışmanın özellikle kadın ve nispeten erkek sporcular için kuersetin takviyesinin laktik asit seviyelerini azalttığı, yorgunluğun gecikmesini sağlayarak daha iyi bir performans gösterebileceğini anlatan bir çalışma olduğu söylenebilmektedir. Anahtar Kelimler: Kuersetin, Resveratrol, Laktik Asit, Yorgunluk, Sportif Performans, Adölesan, Kadın Sporcular, Besin Takviyesi, Atletizm ABSTRACT Investigation of the Effects of Quercetin and Resveratrol Consumption on Lactic Acid Levels and Running Performance of Elite Adolescent Athletics Distance Runners The aim of this study is to investigate the effects of quercetin and resveratrol consumption on the lactic acid levels and running performance of elite adolescent athletics distance runners. 4 women and 4 male adolescent athletes interested in elite athletics in Isparta province participated in the study. The average age of elite adolescent athletes participating in the study was 16.13 ± 2.03 years, the average weight of athletes was 52.02 ± 6.91 kg, and the average height was 168.3 ± 10.61 cm. The study took 3 weeks, one week apart, to measure the effect of quercetin and resveratrol on the performance of adolescent athletes. The two days of each week were taken to the camp and the first week was given placebo, the second week was 500 mg quercetin and the third week was 100 mg resveratrol supplements. On the first day of the camp, they were asked to run 1500 m without reinforcement. Before and after the run, lactic acid measurement was taken and the running times were recorded. On the second day, the same measurements were repeated with supplements. In the study; lactate scout, stopwatch and bioelectric resistance measurement device were used. Paired - T Test and Correlation Tests were used for the analysis of the data obtained, the significance level was accepted as 0.05. Considering the findings obtained; It has been determined that the acute effect of quercetin supplement is significant in lactic acid levels accumulated in female athletes, although it is not statistically significant in males despite the difference in running time, and there is no significant result in resveratrol supplement due to the absence of acute effect. As a result; In quercetin and resveratrol interventions, only quercetin supplementation was found to make a statistically significant difference in female elite adolescent athletes. However, although not statistically significant, differences in running time, which are very important for Athletics sports branch, were encountered. Therefore, it can be said that this study is a study explaining that quercetin supplementation decreases lactic acid levels, especially for female and relatively male athletes, and provides a better performance by providing delay of fatigue. Key Words: Quercetin, Resveratrol, Lactic Acid, Fatigue, Sporty Performance, Adolescent, Women Athletes, Nutritional Supplement, Athletic
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Chapter
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Adequate caloric and carbohydrate intakes are necessary for positive adaptations to exercise training, yet there is limited research examining dietary intake in relation to strength and power in female athletes. The purpose of this study was to determine 1) whether there were significant changes in weekly total caloric and macronutrient consumption, strength, and power, and 2) whether total caloric and macronutrient consumption significantly and positively contributed to changes in strength and power across a controlled eight-week, off-season resistance training program. Eleven collegiate-level female volleyball players were examined on macronutrient consumption, strength, and power at two-week intervals using three-day food logs, 3-repetition maximum bench press and back squat, and vertical jump, respectively. Five assessments were conducted on each subject. Alpha level was set at r < 0.05. Paired samples t-tests showed improvements in body mass index, lean body mass, percent body fat, and lower body strength and power following eight weeks of training (r < .05) despite no significant changes in total calories or macronutrients. Results of a weighted regression analysis indicated that both total caloric consumption and carbohydrate intake influenced lower body power after training (r < .05). However, nutrient intake did not impact strength or power at any of the two-week intervals. We believe these findings are related to the neuromuscular adaptations that occur early in training. A longer resistance training program resulting in gains in muscle cross-sectional area (CSA) may be necessary to further examine the contribution of calories and macronutrients to performance-related variables.
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The research is a field study on the effect of taking protein supplements on a group of players of different ages and comparing them with their counterparts who did not take protein supplements while following a balanced diet and exercise program only. The study included 48 players and volunteers who were divided into three groups according to the age groups A (20-29 years), B (30-39 years) and C (40-50 years), and each group was divided into two parts, the first used protein supplements of 25 grams per day and the second Supplements were not used, and a survey questionnaire was conducted on the foods the players eat as a protein food source. Coach Hussein Anisafi contributed to the selection of the players and gave from his experience, which enriched the study. The study found that the highest frequency of food eaten by the athlete as a protein food source is eggs, followed by chicken breast, and that their trainer is the source of their confidence and guidance towards taking protein supplements and adopting a balanced diet. Protein content on the biceps muscle of players with the age groups of the players, it was found that the players in the young age group A had an increase in muscle amplification higher than other age groups and tended more to take supplements in order to obtain the desired muscle size and shape, while the second age group B They did not get the desired result, but they depended more on the training program and diet more, and this may be due to their long experience in the field of training and the quality of eating. With regard to age group C, the change was slight, as taking protein supplements was not accompanied by a clear change in muscle amplification. Additional types of supplements had to be used other than the supplements used in the study.
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The nature of the deficit underlying age-related muscle wasting remains controversial. To test whether it could be due to a poor anabolic response to dietary amino acids, we measured the rates of myofibrillar and sarcoplasmic muscle protein synthesis (MPS) in 44 healthy young and old men, of similar body build, after ingesting different amounts of essential amino acids (EAA). Basal rates of MPS were indistinguishable, but the elderly showed less anabolic sensitivity and responsiveness of MPS to EAA, possibly due to decreased intramuscular expression, and activation (phosphorylation) after EAA, of amino acid sensing/signaling proteins (mammalian target of rapamycin, mTOR; p70 S6 kinase, or p70(S6k); eukaryotic initiation factor [eIF]4BP-1; and eIF2B). The effects were independent of insulin signaling since plasma insulin was clamped at basal values. Associated with the anabolic deficits were marked increases in NFkappaB, the inflammation-associated transcription factor. These results demonstrate first, EAA stimulate MPS independently of increased insulin availability; second, in the elderly, a deficit in MPS in the basal state is unlikely; and third, the decreased sensitivity and responsiveness of MPS to EAA, associated with decrements in the expression and activation of components of anabolic signaling pathways, are probably major contributors to the failure of muscle maintenance in the elderly. Countermeasures to maximize muscle maintenance should target these deficits.
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This paper compares the efficacy of two widely used weight-loss diets differing in macronutrient composition - a low-carbohydrate diet versus a low-fat diet. Although "a calorie is a calorie" under the controlled conditions of a metabolic unit (i.e., only the level of calorie intake matters and not the source of calories), we conclude that these interrelationships are far more complex in the free-living situation. The different diet-related factors that condition energy balance, including total energy intake, satiety and hunger sensory triggers, and palatability, must be considered when assessing the efficacy of weight-reducing diets of different macronutrient composition.
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The purpose of this investigation was to assess mixed-muscle fractional synthesis rate (FSR) and the expression of genes involved in skeletal muscle remodeling after aerobic exercise in the fasted and fed states. Eight recreationally active males (25 ± 1 yr; Vo(2 max): 52 ± 2 ml·kg(-1)·min(-1)) performed 60-min of cycle ergometry at 72 ± 1% Vo(2 max) on two occasions in a counter-balanced design. Subjects ingested a noncaloric placebo (EX-FAST) or a beverage containing (per kg body wt): 5 kcal, 0.83 g carbohydrate, 0.37 g protein, and 0.03 g fat (EX-FED) immediately and 1 h after exercise. FSR was assessed at rest and following exercise with the use of a l-[ring (2)H(5)]-phenylalanine infusion combined with muscle biopsies at 2 and 6 h postexercise. mRNA expression was assessed at 2 and 6 h postexercise via real-time RT-PCR. FSR was higher (P < 0.05) after exercise in both EX-FAST (0.112 ± 0.010%·h(-1)) and EX-FED (0.129 ± 0.014%·h(-1)) compared with rest (0.071 ± 0.005%·h(-1)). Feeding attenuated the mRNA expression (P < 0.05) of proteolytic factors MuRF-1 (6 h) and calpain-2 (2 and 6 h) postexercise but did not alter FOXO3A, calpain-1, caspase3, or myostatin mRNA expression compared with EX-FAST. Myogenic regulatory factor (MRF4) mRNA was also attenuated (P < 0.05) at 2 and 6 h postexercise in EX-FED compared with EX-FAST. These data demonstrate that a nonexhaustive bout of aerobic exercise stimulates skeletal muscle FSR in the fasted state and that feeding does not measurably enhance FSR between 2 and 6 h after aerobic exercise. Additionally, postexercise nutrient intake attenuates the expression of factors involved in the ubiquitin-proteosome and Ca(2+)-dependent protein degradation pathways. These data provide insight into the role of feeding on muscle protein metabolism during recovery from aerobic exercise.
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The efficacy of chocolate milk (CM) as a recovery beverage following a period of increased training duration (ITD) was studied in intercollegiate soccer players. 13 subjects completed one week of normal 'baseline' training followed by four days of ITD. After each day of ITD, subjects received either a high-carbohydrate (504 kcal; CHO: 122 g; 2 g Fat) or isocaloric CM (504 kcal; 84 g CHO; 28 g Pro; 7 g Fat) recovery beverage. Serum creatine kinase (CK), myoglobin (Mb), muscle soreness, fatigue ratings and isometric quadriceps force (MVC) were obtained prior to ITD, and following 2- and 4-days of ITD. Performance tests (T-drill, vertical jump) were performed within training sessions. Treatments were administered in a randomly counterbalanced protocol, and subjects repeated the procedures with the alternate beverage following a two-week washout period. Mean daily training time and HR increased (p < 0.05) between baseline training and ITD, with no differences between treatments. No treatment*time effects were observed for Mb, muscle soreness, fatigue ratings and MVC. However, serum CK was significantly lower (p < 0.05) following four days of ITD with CM (316.9 +/- 188.3 U.L-1) compared to CHO (431.6 +/- 310.8 U.L-1). No treatment differences were observed for the performance tests. Post-exercise CM provided similar muscle recovery responses to an isocaloric CHO beverage during four-days of ITD. Future studies should investigate if the attenuated CK levels observed with CM have functional significance during more demanding periods of training.
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Weight loss and subsequent body weight maintenance are difficult for obese individuals despite the wide variety of dietary regimens and approaches. A substantial body of scientific evidence has shown that by simply varying the macronutrient distribution and composition of dietary factors, weight losses of varying amounts, longer-term body weight maintenance periods, better appetite regulation, and changes in features of the metabolic syndrome can be achieved. At present, renewed efforts are underway to increase the protein content of weight-loss diets, simultaneously restrict fat consumption to no more than 30%, favor polyunsaturated fat, have carbohydrates account for between 40 and 50% of total energy intake, and promote the consumption of low-glycemic foods. The present article reviews the scientific evidence for the effects of several dietary manipulations and sustainable strategies for weight loss and body weight stability as well as for treating specific features of the metabolic syndrome.
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To examine the influence of dietary protein on lean body mass loss and performance during short-term hypoenergetic weight loss in athletes. In a parallel design, 20 young healthy resistance-trained athletes were examined for energy expenditure for 1 wk and fed a mixed diet (15% protein, 100% energy) in the second week followed by a hypoenergetic diet (60% of the habitual energy intake), containing either 15% (approximately 1.0 g x kg(-1)) protein (control group, n = 10; CP) or 35% (approximately 2.3 g x kg(-1)) protein (high-protein group, n = 10; HP) for 2 wk. Subjects continued their habitual training throughout the study. Total, lean body, and fat mass, performance (squat jump, maximal isometric leg extension, one-repetition maximum (1RM) bench press, muscle endurance bench press, and 30-s Wingate test) and fasting blood samples (glucose, nonesterified fatty acids (NEFA), glycerol, urea, cortisol, free testosterone, free Insulin-like growth factor-1 (IGF-1), and growth hormone), and psychologic measures were examined at the end of each of the 4 wk. Total (-3.0 +/- 0.4 and -1.5 +/- 0.3 kg for the CP and HP, respectively, P = 0.036) and lean body mass loss (-1.6 +/- 0.3 and -0.3 +/- 0.3 kg, P = 0.006) were significantly larger in the CP compared with those in the HP. Fat loss, performance, and most blood parameters were not influenced by the diet. Urea was higher in HP, and NEFA and urea showed a group x time interaction. Fatigue ratings and "worse than normal" scores on the Daily Analysis of Life Demands for Athletes were higher in HP. These results indicate that approximately 2.3 g x kg(-1) or approximately 35% protein was significantly superior to approximately 1.0 g x kg(-1) or approximately 15% energy protein for maintenance of lean body mass in young healthy athletes during short-term hypoenergetic weight loss.
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The essential amino acids (EAA) activate anabolic signalling through mechanisms, which are unclear in detail but include increased signalling through the mammalian target of rapamycin complex 1 (mTORC1). Of all the EAA, the branched chain amino acid (BCAA) leucine has been suggested as the most potent in stimulating protein synthesis, although there have been no studies investigating the effects of each EAA on anabolic signalling pathways. We therefore undertook a systematic analysis of the effect of each EAA on mTORC1 signalling in C2C12 myotubes whereby cells were serum (4 h) and amino acid (1 h) starved before stimulation with 2 mM of each amino acid. Immunoblotting was used to detect phosphorylated forms of protein kinase B (Akt)/mTORC1 signalling enzymes. The phosphorylation of Akt was unchanged by incubation with EAA. Phosphorylation of mTOR and 4E binding protein-1 (4EBP1) were increased 1.67 +/- 0.1-fold and 2.5 +/- 0.1-fold, respectively, in response to leucine stimulation but not in response to any other EAA. The phosphorylation of ribosomal s6 kinase (p70S6K1) was increased by stimulation with all EAA with the exceptions of isoleucine and valine. However, the increase with leucine was significantly greater, 5.9 +/- 0.3-fold compared to 1.6-2.0-fold for the non-BCAA EAA. This pattern of activation was identical in ribosomal protein s6 (RPS6) with the additional effect of leucine being 3.8 +/- 0.3-fold versus 1.5-2.0-fold. Phosphorylation of eukaryotic initiation/elongation factors eIF2alpha and eEF2 were unaffected by EAA. We conclude that leucine is unique amongst the amino acids in its capacity to stimulate both mTOR and 4EBP1 phosphorylation and to enhance p70S6K1 signalling.
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Critically ill patients are characterized by increased loss of muscle mass, partially attributed to sepsis and multiple organ failure, as well as immobilization. Recent studies have shown that electrical muscle stimulation (EMS) may be an alternative to active exercise in chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) patients with myopathy. The aim of our study was to investigate the EMS effects on muscle mass preservation of critically ill patients with the use of ultrasonography (US). Forty-nine critically ill patients (age: 59 +/- 21 years) with an APACHE II admission score >or=13 were randomly assigned after stratification upon admission to receive daily EMS sessions of both lower extremities (EMS-group) or to the control group (control group). Muscle mass was evaluated with US, by measuring the cross sectional diameter (CSD) of the vastus intermedius and the rectus femoris of the quadriceps muscle. Twenty-six patients were finally evaluated. Right rectus femoris and right vastus intermedius CSD decreased in both groups (EMS group: from 1.42 +/- 0.48 to 1.31 +/- 0.45 cm, P = 0.001 control group: from 1.59 +/- 0.53 to 1.37 +/- 0.5 cm, P = 0.002; EMS group: from 0.91 +/- 0.39 to 0.81 +/- 0.38 cm, P = 0.001 control group: from 1.40 +/- 0.64 to 1.11 +/- 0.56 cm, P = 0.004, respectively). However, the CSD of the right rectus femoris decreased significantly less in the EMS group (-0.11 +/- 0.06 cm, -8 +/- 3.9%) as compared to the control group (-0.21 +/- 0.10 cm, -13.9 +/- 6.4%; P < 0.05) and the CSD of the right vastus intermedius decreased significantly less in the EMS group (-0.10 +/- 0.05 cm, -12.5 +/- 7.4%) as compared to the control group (-0.29 +/- 0.28 cm, -21.5 +/- 15.3%; P < 0.05). EMS is well tolerated and seems to preserve the muscle mass of critically ill patients. The potential use of EMS as a preventive and rehabilitation tool in ICU patients with polyneuromyopathy needs to be further investigated. clinicaltrials.gov: NCT00882830.
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It has been suggested that a protein hydrolysate, as opposed to its intact protein, is more easily digested and absorbed from the gut, which results in greater plasma amino acid availability and a greater muscle protein synthetic response. We aimed to compare dietary protein digestion and absorption kinetics and the subsequent muscle protein synthetic response to the ingestion of a single bolus of protein hydrolysate compared with its intact protein in vivo in humans. Ten elderly men (mean +/- SEM age: 64 +/- 1 y) were randomly assigned to a crossover experiment that involved 2 treatments in which the subjects consumed a 35-g bolus of specifically produced L-[1-(13)C]phenylalanine-labeled intact casein (CAS) or hydrolyzed casein (CASH). Blood and muscle-tissue samples were collected to assess the appearance rate of dietary protein-derived phenylalanine in the circulation and subsequent muscle protein fractional synthetic rate over a 6-h postprandial period. The mean (+/-SEM) exogenous phenylalanine appearance rate was 27 +/- 6% higher after ingestion of CASH than after ingestion of CAS (P < 0.001). Splanchnic extraction was significantly lower in CASH compared with CAS treatment (P < 0.01). Plasma amino acid concentrations increased to a greater extent (25-50%) after the ingestion of CASH than after the ingestion of CAS (P < 0.01). Muscle protein synthesis rates averaged 0.054 +/- 0.004% and 0.068 +/- 0.006%/h in the CAS and CASH treatments, respectively (P = 0.10). Ingestion of a protein hydrolysate, as opposed to its intact protein, accelerates protein digestion and absorption from the gut, augments postprandial amino acid availability, and tends to increase the incorporation rate of dietary amino acids into skeletal muscle protein.
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Background: The possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year. Methods: We randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content. Results: At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years, weight loss remained similar in those who were assigned to a diet with 15% protein and those assigned to a diet with 25% protein (3.0 and 3.6 kg, respectively); in those assigned to a diet with 20% fat and those assigned to a diet with 40% fat (3.3 kg for both groups); and in those assigned to a diet with 65% carbohydrates and those assigned to a diet with 35% carbohydrates (2.9 and 3.4 kg, respectively) (P>0.20 for all comparisons). Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight. Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended). The diets improved lipid-related risk factors and fasting insulin levels. Conclusions: Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize. (ClinicalTrials.gov number, NCT00072995.)
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This study examined the effects of 3 recovery drinks on endurance performance following glycogen-depleting exercise. Nine trained male cyclists performed 3 experimental trials, in a randomized counter-balanced order, consisting of a glycogen-depleting trial, a 4-h recovery period, and a cycle to exhaustion at 70% power at maximal oxygen uptake. At 0 and 2 h into the recovery period, participants consumed chocolate milk (CM), a carbohydrate replacement drink (CR), or a fluid replacement drink (FR). Participants cycled 51% and 43% longer after ingesting CM (32 +/- 11 min) than after ingesting CR (21 +/- 8 min) or FR (23 +/- 8 min). CM is an effective recovery aid after prolonged endurance exercise for subsequent exercise at low-moderate intensities.
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In this review we discuss current findings in the human skeletal muscle literature describing the acute influence of nutrients (leucine-enriched essential amino acids in particular) and resistance exercise on muscle protein synthesis and mammalian target of rapamycin complex 1 (mTORC1) signaling. We show that essential amino acids and an acute bout of resistance exercise independently stimulate human skeletal muscle protein synthesis. It also appears that ingestion of essential amino acids following resistance exercise leads to an even larger increase in the rate of muscle protein synthesis compared with the independent effects of nutrients or muscle contraction. Until recently the cellular mechanisms responsible for controlling the rate of muscle protein synthesis in humans were unknown. In this review, we highlight new studies in humans that have clearly shown the mTORC1 signaling pathway is playing an important regulatory role in controlling muscle protein synthesis in response to nutrients and/or muscle contraction. We propose that essential amino acid ingestion shortly following a bout of resistance exercise is beneficial in promoting skeletal muscle growth and may be useful in counteracting muscle wasting in a variety of conditions such as aging, cancer cachexia, physical inactivity, and perhaps during rehabilitation following trauma or surgery.
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We investigated the effect of carbohydrate and protein hydrolysate ingestion on whole-body and muscle protein synthesis during a combined endurance and resistance exercise session and subsequent overnight recovery. Twenty healthy men were studied in the evening after consuming a standardized diet throughout the day. Subjects participated in a 2-h exercise session during which beverages containing both carbohydrate (0.15 g x kg(-1) x h(-1)) and a protein hydrolysate (0.15 g x kg(-1) x h(-1)) (C+P, n = 10) or water only (W, n = 10) were ingested. Participants consumed 2 additional beverages during early recovery and remained overnight at the hospital. Continuous i.v. infusions with L-[ring-(13)C(6)]-phenylalanine and L-[ring-(2)H(2)]-tyrosine were applied and blood and muscle samples were collected to assess whole-body and muscle protein synthesis rates. During exercise, whole-body and muscle protein synthesis rates increased by 29 and 48% with protein and carbohydrate coingestion (P < 0.05). Fractional synthetic rates during exercise were 0.083 +/- 0.011%/h in the C+P group and 0.056 +/- 0.003%/h in the W group, (P < 0.05). During subsequent overnight recovery, whole-body protein synthesis was 19% greater in the C+P group than in the W group (P < 0.05). However, mean muscle protein synthesis rates during 9 h of overnight recovery did not differ between groups and were 0.056 +/- 0.004%/h in the C+P group and 0.057 +/- 0.004%/h in the W group (P = 0.89). We conclude that, even in a fed state, protein and carbohydrate supplementation stimulates muscle protein synthesis during exercise. Ingestion of protein with carbohydrate during and immediately after exercise improves whole-body protein synthesis but does not further augment muscle protein synthesis rates during 9 h of subsequent overnight recovery.
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This randomized double-blind cross-over study assessed protein (PRO) requirements during the early stages of intensive bodybuilding training and determined whether supplemental PRO intake (PROIN) enhanced muscle mass/strength gains. Twelve men [22.4 +/- 2.4 (SD) yr] received an isoenergetic PRO (total PROIN 2.62 g.kg-1.day-1) or carbohydrate (CHO; total PROIN 1.35 g.kg-1.day-1) supplement for 1 mo each during intensive (1.5 h/day, 6 days/wk) weight training. On the basis of 3-day nitrogen balance (NBAL) measurements after 3.5 wk on each treatment (8.9 +/- 4.2 and -3.4 +/- 1.9 g N/day, respectively), the PROIN necessary for zero NBAL (requirement) was 1.4-1.5 g.kg-1.day-1. The recommended intake (requirement + 2 SD) was 1.6-1.7 g.kg-1.day-1. However, strength (voluntary and electrically evoked) and muscle mass [density, creatinine excretion, muscle area (computer axial tomography scan), and biceps N content] gains were not different between diet treatments. These data indicate that, during the early stages of intensive bodybuilding training, PRO needs are approximately 100% greater than current recommendations but that PROIN increases from 1.35 to 2.62 g.kg-1.day-1 do not enhance muscle mass/strength gains, at least during the 1st mo of training. Whether differential gains would occur with longer training remains to be determined.
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The effects of regular submaximal exercise on dietary protein requirements, whole body protein turnover, and urinary 3-methylhistidine were determined in six young (26.8 +/- 1.2 yr) and six middle-aged (52.0 +/- 1.9 yr) endurance-trained men. They consumed 0.6, 0.9, or 1.2 g.kg-1.day-1 of high-quality protein over three separate 10-day periods, while maintaining training and constant body weight. Nitrogen measurements in diet, urine, and stool and estimated sweat and miscellaneous nitrogen losses showed that they were all in negative nitrogen balance at a protein intake of 0.6 g.kg-1.day-1. The estimated protein requirement was 0.94 +/- 0.05 g.kg-1.day-1 for the 12 men, with no effect of age. Whole body protein turnover, using [15N]glycine as a tracer, and 3-methylhistidine excretion were not different in the two groups, despite lower physical activity of the middle-aged men. Protein intake affected whole body protein flux and synthesis but not 3-methylhistidine excretion. These data show that habitual endurance exercise was associated with dietary protein needs greater than the current Recommended Dietary Allowance of 0.8 g.kg-1.day-1. However, whole body protein turnover and 3-methylhistidine excretion were not different from values reported for sedentary men.
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Part of the authoritative series on reference values for nutrient intakes , this new release establishes a set of reference values for dietary energy and the macronutrients: carbohydrate (sugars and starches), fiber, fat, fatty acids, cholesterol, protein, and amino ...
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Amino acids act to regulate multiple processes related to gene expression, including modulation of the function of the proteins that mediate messenger RNA (mRNA) translation. By modulating the function of translation initiation and elongation factors, amino acids regulate the translation of mRNA on a global scale and also act to cause preferential changes in the translation of mRNAs encoding particular proteins or families of proteins. However, amino acids do not directly regulate the function of translation initiation and elongation factors, but instead modulate signaling through pathways traditionally considered to be solely involved in mediating the action of hormones. The best-characterized example of amino acid-induced regulation of a signal transduction pathway is one involving a protein kinase referred to as the mammalian target of rapamycin (mTOR), through which the branched-chain amino acids, particularly leucine, act to modulate the function of proteins engaged in both global mRNA translation and the selection of specific mRNAs for translation. Less understood at this point in time is evidence suggesting that amino acids also act to regulate mRNA translation through mTOR-independent mechanisms. The goal of the present review is to briefly summarize studies, primarily those performed in the laboratories of the authors, that focus on the role of the branched-chain amino acids in the regulation of mRNA translation in skeletal muscle.
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It is unclear whether low-carbohydrate, high-protein, weight-loss diets benefit body mass and composition beyond energy restriction alone. The objective was to use meta-regression to determine the effects of variations in protein and carbohydrate intakes on body mass and composition during energy restriction. English-language studies with a dietary intervention of > or =4200 kJ/d (1000 kcal/d), with a duration of > or =4 wk, and conducted in subjects aged > or =19 y were considered eligible for inclusion. A self-reported intake in conjunction with a biological marker of macronutrient intake was required as a minimum level of dietary control. A total of 87 studies comprising 165 intervention groups met the inclusion criteria. After control for energy intake, diets consisting of < or =35-41.4% energy from carbohydrate were associated with a 1.74 kg greater loss of body mass, a 0.69 kg greater loss of fat-free mass, a 1.29% greater loss in percentage body fat, and a 2.05 kg greater loss of fat mass than were diets with a higher percentage of energy from carbohydrate. In studies that were conducted for >12 wk, these differences increased to 6.56 kg, 1.74 kg, 3.55%, and 5.57 kg, respectively. Protein intakes of >1.05 g/kg were associated with 0.60 kg additional fat-free mass retention compared with diets with protein intakes < or =1.05 g/kg. In studies conducted for >12 wk, this difference increased to 1.21 kg. No significant effects of protein intake on loss of either body mass or fat mass were observed. Low-carbohydrate, high-protein diets favorably affect body mass and composition independent of energy intake, which in part supports the proposed metabolic advantage of these diets.
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The mTORC1 kinase promotes growth in response to growth factors, energy levels, and amino acids, and its activity is often deregulated in disease. The Rag GTPases interact with mTORC1 and are proposed to activate it in response to amino acids by promoting mTORC1 translocation to a membrane-bound compartment that contains the mTORC1 activator, Rheb. We show that amino acids induce the movement of mTORC1 to lysosomal membranes, where the Rag proteins reside. A complex encoded by the MAPKSP1, ROBLD3, and c11orf59 genes, which we term Ragulator, interacts with the Rag GTPases, recruits them to lysosomes, and is essential for mTORC1 activation. Constitutive targeting of mTORC1 to the lysosomal surface is sufficient to render the mTORC1 pathway amino acid insensitive and independent of Rag and Ragulator, but not Rheb, function. Thus, Rag-Ragulator-mediated translocation of mTORC1 to lysosomal membranes is the key event in amino acid signaling to mTORC1.
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The balance between muscle protein synthesis (MPS) and muscle protein breakdown (MPB) is dependent on protein consumption and the accompanying hyperaminoacidemia, which stimulates a marked rise in MPS and mild suppression of MPB. In the fasting state, however, MPS declines sharply and MPB is increased slightly. Ultimately, the balance between MPS and MPB determines the net rate of muscle growth. Accretion of new muscle mass beyond that of normal growth can occur following periods of intense resistance exercise. Such muscle accretion is an often sought-after goal of athletes. There needs to be, however, an increased appreciation of the role that preservation of muscle can play in offsetting morbidities associated with the sarcopenia of aging, such as type 2 diabetes and declines in metabolic rate that can lead to fat mass accumulation followed by the onset or progression of obesity. Emerging evidence shows that consumption of different types of proteins can have different stimulatory effects on the amplitude and possibly duration that MPS is elevated after feeding; this may be particularly significant after resistance exercise. This effect may be due to differences in the fundamental amino acid composition of the protein (i.e., its amino acid score) and its rate of digestion. Milk proteins, specifically casein and whey, are the highest quality proteins and are quite different in terms of their rates of digestion and absorption. New data suggest that whey protein is better able to support MPS than is soy protein, a finding that may explain the greater ability of whey protein to support greater net muscle mass gains with resistance exercise. This review focuses on evidence showing the differences in responses of MPS, and ultimately muscle protein accretion, to consumption of milk- and soy-based supplemental protein sources in humans.