Bill I. Campbell’s research while affiliated with University of South Florida and other places

What is this page?


This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.

Publications (34)


Figure 1. Potential health benefits of ω-3 PUFA supplementation in athletes (illustration by Stephen Somers, Milwaukee, WI, USA).
Figure 2. Prolonged maximal exercise can induce leaky gut (adapted from Dr. Jeremy Townsend).
Summary of studies investigating the effect of ω-3 PUFA supplementation on endurance exercise.
ω-3 PUFAs studies on cognition and psychological health in athletes.
International Society of Sports Nutrition Position Stand: Long-Chain Omega-3 Polyunsaturated Fatty Acids
  • Literature Review
  • File available

January 2025

·

318 Reads

·

·

·

[...]

·

Position Statement: The International Society of Sports Nutrition (ISSN) presents this position based on a critical examination of the literature surrounding the effects of long-chain omega-3 polyunsaturated fatty acid (ω-3 PUFA) supplementation on exercise performance, recovery, and brain health. This position stand is intended to provide a scientific foundation for athletes, dietitians, trainers, and other practitioners regarding the effects of supplemental ω-3 PUFA in healthy and athletic populations. The following conclusions represent the official position of the ISSN: Athletes may be at a higher risk for ω-3 PUFA insufficiency. Diets rich in ω-3 PUFA, including supplements, are effective strategies for increasing ω-3 PUFA levels. ω-3 PUFA supplementation, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has been shown to enhance endurance capacity and cardiovascular function during aerobic-type exercise. ω-3 PUFA supplementation may not confer a muscle hypertrophic benefit in young adults. ω-3 PUFA supplementation in combination with resistance training may improve strength in a dose- and duration-dependent manner. ω-3 PUFA supplementation may decrease subjective measures of muscle soreness following intense exercise. ω-3 PUFA supplementation can positively affect various immune cell responses in athletic populations. Prophylactic ω-3 PUFA supplementation may offer neuroprotective benefits in athletes exposed to repeated head impacts. ω-3 PUFA supplementation is associated with improved sleep quality. ω-3 PUFA are classified as prebiotics; however, studies on the gut microbiome and gut health in athletes are currently lacking.

Download

Figure 1. HMB (β-hydroxy-β-methylbutyrate) is the active metabolite of leucine, a branched chain amino acid. HMB is naturally occurring in humans and animals.
Summary of studies that investigated the effects of HMB plus creatine (CrM) on athletic performance in young adults.
International society of sports nutrition position stand: β-hydroxy-β-methylbutyrate (HMB)

December 2024

·

140 Reads

Position Statement: The International Society of Sports Nutrition (ISSN) bases the following position stand on an analysis of the literature regarding the effects of β-Hydroxy-β-Methylbutyrate (HMB). The following 12 points have been approved by the Research Committee of the Society: 1. HMB is a metabolite of the amino acid leucine that is naturally produced in both humans and other animals. Two forms of HMB have been studied: Calcium HMB (HMB-Ca) and a free acid form of HMB (HMB-FA). HMB-FA appears to lead to increased appearance of HMB in the bloodstream when compared to HMB-Ca, though recent results are mixed. 2. The available safety/toxicity data suggest that chronic HMB-Ca and HMB-FA consumption are safe for oral HMB supplementation in humans up to at least one year. 3. There are no negative effects of HMB-Ca and HMB-FA on glucose tolerance and insulin sensitivity in humans. There may be improvements in glucose metabolism in younger adults. 4. The primary mode of action of HMB appears to be through its dual mechanism to enhance muscle protein synthesis and suppress muscle protein breakdown. HMB's activation of mTORC1 is independent of the leucine-sensing pathway (Sestrin2-GATOR2 complex). 5. HMB may help reduce muscle damage and promote muscle recovery, which can promote muscle growth/repair. HMB may also have anti-inflammatory effects, which could contribute to reducing muscle damage and soreness. 6. HMB consumption in close proximity to an exercise bout may be beneficial to increase muscle protein synthesis and attenuate the inflammatory response. HMB can provide a beneficial physiological effect when consumed both acutely and chronically in humans. 7. Daily HMB supplementation (38 mg/kg body weight) in combination with exercise training may improve body composition through increasing lean mass and/or decreasing fat mass with benefits in participants across age, sex, and training status. The most pronounced of these improvements in body composition with HMB have been observed in studies with robust resistance training programs and dietary control. 8. HMB may improve strength and power in untrained individuals, but its performance benefits in trained athletes are mixed and increase with an increase in study duration (>6 weeks). HMB's beneficial effects on athletic performance are thought to be driven by improved recovery. 9. HMB supplementation appears to potentially have a positive impact on aerobic performance, especially in trained athletes. The mechanisms of the effects are unknown. 10. HMB supplementation may be important in a non-exercising sedentary and aging population to improve muscle strength, functionality, and muscle quality. The effects of HMB supplementation with exercise are varied, but the combination may have a beneficial effect on the treatment of age-associated sarcopenia under select conditions. 11. HMB may be effective in countering muscle disuse atrophy during periods of inactivity due to illness or injury. The modulation of mitochondrial dynamics and lipid metabolism by HMB may be a potential mechanism for preventing disuse atrophy and aiding rehabilitation beyond HMB's effects on rates of muscle protein synthesis and degradation. 12. The efficacy of HMB in combination with certain nutrients may be enhanced under select conditions.



International society of sports nutrition position stand: ketogenic diets

ABSTRACT Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the use of a ketogenic diet in healthy exercising adults, with a focus on exercise performance and body composition. However, this review does not address the use of exogenous ketone supplements. The following points summarize the position of the ISSN: 1. A ketogenic diet induces a state of nutritional ketosis, which is generally defined as serum ketone levels above 0.5 mM. While many factors can impact what amount of daily carbohydrate intake will result in these levels, a broad guideline is a daily dietary carbohydrate intake of less than 50 grams per day. 2. Nutritional ketosis achieved through carbohydrate restriction and a high dietary fat intake is not intrinsically harmful and should not be confused with ketoacidosis, a life-threatening condition most commonly seen in clinical populations and metabolic dysregulation. 3. A ketogenic diet has largely neutral or detrimental effects on athletic performance compared to a diet higher in carbohydrates and lower in fat, despite achieving significantly elevated levels of fat oxidation during exercise (~1.5 g/min). 4. The endurance effects of a ketogenic diet may be influenced by both training status and duration of the dietary intervention, but further research is necessary to elucidate these possibilities. All studies involving elite athletes showed a performance decrement from a ketogenic diet, all lasting six weeks or less. Of the two studies lasting more than six weeks, only one reported a statistically significant benefit of a ketogenic diet. 5. A ketogenic diet tends to have similar effects on maximal strength or strength gains from a resistance training program compared to a diet higher in carbohydrates. However, a minority of studies show superior effects of non-ketogenic comparators. 6. When compared to a diet higher in carbohydrates and lower in fat, a ketogenic diet may cause greater losses in body weight, fat mass, and fat-free mass, but may also heighten losses of lean tissue. However, this is likely due to differences in calorie and protein intake, as well as shifts in fluid balance. 7. There is insufficient evidence to determine if a ketogenic diet affects males and females differently. However, there is a strong mechanistic basis for sex differences to exist in response to a ketogenic diet.



The Effects of a High-Carbohydrate, High-Glycemic Load Hypocaloric Diet on Body Fat Loss - A Case Study

June 2024

·

563 Reads

The carbohydrate-insulin model (CIM) posits that obesity is caused by a high glycemic load diet that elicits a dysregulated hormonal response that inhibits fat mobilization and promotes fat deposition in adipose tissue (1). The Energy Balance Model (EBM) proposes that the brain is the primary organ responsible for body weight regulation from a combination of external signals (from the food environment) and internal signals (peripheral organs) to control food intake (2). Some have taken the etiological and theoretical basis of CIM and deviated from it to assert that high-carbohydrate diets (even when consumed within an energy deficit) are not effective for losing body fat. Therefore, the purpose of this case study was to challenge this application by exploring a high carbohydrate, high glycemic load hypocaloric diet to induce fat loss in a resistance-trained obese male. The dietary protocol targeted a 25% caloric deficit, with approximately 60% of calories coming from carbohydrates (CHO) and 20% coming from protein (PRO) and fats equally. Refeeds and diet breaks were accounted for in the targeted deficit. The exercise program consisted of whole-body resistance training (3x/week) and aerobic exercise (3x/week). Body composition (4-compartment model) and select blood markers predictive of metabolic dysfunction (fasting glucose, fasting insulin, and hemoglobin A1C) were assessed at the beginning and end of the 30-week intervention. B-mode ultrasound muscle thickness measurements, resting energy expenditure, and vitals were also assessed every 10-weeks. GI were matched to each food item and glycemic loads were subsequently calculated. Weekly averages were calculated for both. Data is presented descriptively. Average values for glycemic index (GI) and glycemic load during the study were 54 and 36, respectively. The average daily caloric intake was approximately 2,400 kcals, equating to a caloric deficit of ~22% per day. The macronutrient composition of the diet was 58% CHO, 14% PRO (0.83 g/kg/day), and 28% fats. Body weight was reduced by 11% (from 104.8 to 93.2 kgs) and losses were solely from fat stores. Fat mass declined from 31.1 to 18.9 kgs (-12.2 kgs), which was equivalent to a 9.4% decrease in body fat (from 29.7 to 20.3%). Fat-free mass was maintained during the study (73.6 to 74.3 kgs). Fasting glucose decreased from 95 to 91 mg/dL, fasting insulin decreased from 6.9 to 5.2 uIU/mL, and hemoglobin A1C slightly increased from 5.2 to 5.4%. Figure 1. Fat mass loss over the entire study period. BL = baseline BACKGROUND


Figure 1. An overview of testing sessions.
Figure 2. (A) REE values over the 180-min study period; (B) change from baseline in Resting Energy Expenditure; error bars represent 95% confidence intervals; * indicates statistical significance at the p ≤ 0.05 level.
Participant characteristics.
The Acute Effects of a Commercially Available Caffeinated and Caffeine-Free Thermogenic Dietary Supplement on Resting Energy Expenditure, Hunger, and Hemodynamic Responses

February 2024

·

51 Reads

·

1 Citation

Nutraceuticals

There has been a rise in popularity of “stimulant-free” or caffeine-free fat loss supplements, but it is not well understood whether those fat loss supplements are effective at enhancing thermogenesis without caffeine’s influence. The purpose of this study was to examine the effects of a caffeinated and non-caffeinated commercially available fat loss supplement on resting energy expenditure (REE), hunger, and hemodynamic variables in healthy adults. Twenty-five healthy male and female participants completed three separate laboratory visits after overnight fasts. Baseline assessments of REE, subjective hunger, heart rate (HR), and blood pressure (BP) were followed by ingestion of a caffeinated (Phoenix, Legion®; CAF), non-caffeinated (Phoenix Caffeine-Free, Legion®; NCAF), or placebo (PL) fat loss supplement. REE, hunger, HR, and BP assessments were repeated at 60-, 120-, and 180-min post-ingestion. CAF, but not NCAF, significantly elevated REE greater than PL at all time points (p < 0.05). NCAF significantly reduced hunger compared to CAF and PL at the 120-min time point (p = 0.006). CAF significantly increased diastolic BP 60-min post-ingestion and significantly increased systolic BP 120- and 180-min post-ingestion compared to NCAF and PL. Further research is warranted with respect to investigating non-caffeinated ingredients and their effects on REE.


Study selection flow chart.
Forest plots for changes in absolute fat mass (kg) [13,14,18,19,21,22].
Forest plot for changes in body fat percentage [13,14,16,17,18,20,22,23,24,27].
Risk of bias assessment [13,14,16,17,18,19,20,21,22,23,24,27].
Resistance Exercise and Creatine Supplementation on Fat Mass in Adults < 50 Years of Age: A Systematic Review and Meta-Analysis

October 2023

·

244 Reads

·

6 Citations

The combination of resistance exercise and creatine supplementation has been shown to decrease body fat percentage in adults ≥ 50 years of age. However, the effect on adults < 50 years of age is currently unknown. To address this limitation, we systematically reviewed the literature and performed several meta-analyses comparing studies that included resistance exercise and creatine supplementation to resistance exercise and placebo on fat mass and body fat percentage Twelve studies were included, involving 266 participants. Adults (<50 years of age) who supplemented with creatine and performed resistance exercise experienced a very small, yet significant reduction in body fat percentage (−1.19%, p = 0.006); however, no difference was found in absolute fat mass (−0.18 kg, p = 0.76). Collectively, in adults < 50 years of age, the combination of resistance exercise and creatine supplementation produces a very small reduction in body fat percentage without a corresponding decrease in absolute fat mass.


Figure 2. The effect of 15 g of free-form EAA vs 70 g of lean beef protein and mixed meal ingestion on plasma EAA kinetics. Adapted from references [50,51].
Figure 3. Muscle net balance of phenylalanine (umol/kg/min) during fasting, resistance exercise alone (RE), complete amino acid administration/infusion alone (AA), and with combined AA and RE. An interactive effect between RE and AA administration is demonstrated. Data derived from references [9,66].
Dietary requirements of essential amino acids and safe upper limit of consumption for adults.
International society of sports nutrition position stand: essential amino acid supplementation on skeletal muscle and Performance

October 2023

·

1,627 Reads

·

21 Citations

Position Statement: The International Society of Sports Nutrition (ISSN) presents this position based on a critical examination of literature surrounding the effects of essential amino acid (EAA) supplementation on skeletal muscle maintenance and performance. This position stand is intended to provide a scientific foundation to athletes, dietitians, trainers, and other practitioners as to the benefits of supplemental EAA in both healthy and resistant (aging/clinical) populations. EAAs are crucial components of protein intake in humans, as the body cannot synthesize them. The daily recommended intake (DRI) for protein was established to prevent deficiencies due to inadequate EAA consumption. The following conclusions represent the official position of the Society: 1. Initial studies on EAAs’ effects on skeletal muscle highlight their primary role in stimulating muscle protein synthesis (MPS) and turnover. Protein turnover is critical for replacing degraded or damaged muscle proteins, laying the metabolic foundation for enhanced functional performance. Consequently, research has shifted to examine the effects of EAA supplementation – with and without the benefits of exercise – on skeletal muscle maintenance and performance. 2. Supplementation with free-form EAAs leads to a quick rise in peripheral EAA concentrations, which in turn stimulates MPS. 3. The safe upper limit of EAA intake (amount), without inborn metabolic disease, can easily accommodate additional supplementation. 4. At rest, stimulation of MPS occurs at relatively small dosages (1.5–3.0 g) and seems to plateau at around 15–18 g. 5. The MPS stimulation by EAAs does not require non-essential amino acids. 6. Free-form EAA ingestion stimulates MPS more than an equivalent amount of intact protein. 7. Repeated EAA-induced MPS stimulation throughout the day does not diminish the anabolic effect of meal intake. 8. Although direct comparisons of various formulas have yet to be investigated, aging requires a greater proportion of leucine to overcome the reduced muscle sensitivity known as “anabolic resistance.” 9. Without exercise, EAA supplementation can enhance functional outcomes in anabolic-resistant populations. 10. EAA requirements rise in the face of caloric deficits. During caloric deficit, it’s essential to meet whole-body EAA requirements to preserve anabolic sensitivity in skeletal muscle.



Citations (20)


... Moreover, it has been shown that creatine supplementation may be more effective in studies including participants > 50 years of age, as creatine supplementation may counteract the age-related reduction in muscle strength [3,11,12]. Interestingly, only one recent meta-analysis focused on the effect of creatine supplementation on fat mass in younger adults (under 50 years of age) has been published [13]. Consequently, the effect of creatine supplementation on strength gains from resistance training in adults under 50 years of age remains unknown to date. ...

Reference:

Effects of Creatine Supplementation and Resistance Training on Muscle Strength Gains in Adults <50 Years of Age: A Systematic Review and Meta-Analysis
Resistance Exercise and Creatine Supplementation on Fat Mass in Adults < 50 Years of Age: A Systematic Review and Meta-Analysis

... However, it is not yet clear which of these most effectively enhances exercise outcomes. Nevertheless, the International Society of Sports Nutrition has recently supported the intake of EAAs in clinical conditions and aging, emphasizing the need for further research on the EAA profile, as those richer in leucine appear to elicit a greater anabolic response [57]. Nevertheless, a key limitation in not consuming adequate amounts of protein and micronutrients is insufficient intake of food and energy. ...

International society of sports nutrition position stand: essential amino acid supplementation on skeletal muscle and Performance

... Moreover, considering the impact of genetics on coffee metabolism, future research should take genetic factors into account. Since genetic variations can influence caffeine metabolism and individual responses, analyzing these molecular markers will contribute to obtaining more comprehensive and reliable results [30][31][32][33][34][35][36]. Furthermore, the study utilized generic formulations of coffee and energy drinks, but participants may have based their responses on preferences for specific brands, potentially influencing their expectations and perceptions. ...

International society of sports nutrition position stand: coffee and sports performance

... Accordingly, the present study explored the association between narcissism (grandiose and vulnerable narcissism) and problematic muscularityoriented eating, also addressing the potential involvement of self-esteem and muscle dysmorphia among bodybuilding athletes. The focus on bodybuilding relies on the view that, unlike other sports that test specific skills through athletes' performance, bodybuilding focuses on aesthetic qualities, including muscle size, low body fat, and overall symmetry (Rukstela et al., 2023). To satisfy these criteria, bodybuilders typically engage in a long dieting period to gain muscle mass. ...

Bodybuilding Coaching Strategies Meet Evidence-Based Recommendations: A Qualitative Approach

Journal of Functional Morphology and Kinesiology

... 9 This is supported 5 Jie Kang, Nutrition and metabolism in sports, exercise and health (2nd edition., Taylor and Francis, 2018, p 22. 6 Ibid, p 23. 7 Travis D. Thomas In relation to carbohydrates, there needs to be mentioned fibre as it is a class made out of polysaccharides and, to be precise, consists of cellulose, hemicelluloses, pectins, gums, and mucilages as well as the non-carbohydrate lignin. 10 There are two forms of fibressoluble and insoluble. The former are responsible for a delay in stomach emptying (which means keeping your body satisfied for longer and can, therefore, prevent unwanted hunger). ...

International society of sports nutrition position stand: nutritional concerns of the female athlete

... In a study of dietary supplement-related exposures reported to US poison centers (PCs), energy products accounted for the greatest proportion of serious medical outcomes [18]. Multiple health organizations, including the American Academy of Pediatrics, warn that there is no safe amount of energy drink consumption for children and adolescents [6,[19][20][21][22][23] and a report from members of the US Congress warned of harmful marketing of caffeine energy drinks to adolescents [24]. Despite this, from 2008 to 2015, children < 6 years old represented the highest percentage (42.3%) of caffeine-related exposures reported to US PCs, and youth < 20 years old accounted for more than two-thirds of these exposures [25]. ...

International society of sports nutrition position stand: energy drinks and energy shots

... From a nutritional perspective, rather than using a continuous and aggressive energy deficit, the application of a high-protein diet with intermittent and progressive energy restrictions plus resistance training (RT) might preserve fat-free mass (FFM) (2) and enhance dietary adherence (3) during body recomposition. The characteristics and effects of diet refeeds and diet breaks during a physique contest preparation are discussed elsewhere (4) albeit short-term benefits of the latter seems debatable in resistance-trained females (5). Creatine monohydrate is another valuable nutritional strategy that should be considered (6). ...

The Effects of Intermittent Diet Breaks during 25% Energy Restriction on Body Composition and Resting Metabolic Rate in Resistance-Trained Females: A Randomized Controlled Trial

... Exposure to occupational-related, environmental stressors (e.g. products of incomplete combustion, smoke inhalation, heat stress) coupled with lifestyle stressors (e.g. disrupted sleep patterns, frequent snacking/feeding habits, alcohol abuse, and psychological stressors, such as family separation, trauma, or dual-stress cognitive challenges) can promote progression of cardiovascular disease (CVD) and lead to premature mortality [1][2][3][4][5][6][7]. Firefighting has also been reported to elevate markers of inflammation and oxidative stress [8][9][10][11][12][13]. ...

International society of sports nutrition position stand: tactical athlete nutrition International society of sports nutrition position stand: tactical athlete nutrition

... This aligns with the findings of Maughan et al., in which no sex differences were apparent when performing forearm flexions with 80-90% of 1RM to momentary concentric failure [47]. Conversely, a 2022 investigation by Lewis and colleagues [48], noted females consistently were able to perform more dumbbell bicep curls with a 10RM than their male counterparts. These differences in findings likely stem from the relative intensity used. ...

Sex Differences May Exist for Performance Fatigue but Not Recovery After Single-Joint Upper-Body and Lower-Body Resistance Exercise
  • Citing Article
  • March 2022

The Journal of Strength and Conditioning Research

... Additionally, these analyses omitted physiological outcomes associated with NaHCO₃. Similarly, a review (Grgic et al., 2021) has primarily focused on performance metrics while overlooking physiological effects. Furthermore, both the aforementioned meta-analysis and narrative review are limited in scope and have become outdated with the publication of new studies Newbury et al., 2024). ...

International Society of Sports Nutrition position stand sodium bicarbonate and exercise performance