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Meta-analysis: Effect of exercise, with or without dieting, on the body composition of overweight subjects

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Abstract

To determine if physical training conserves fat-free mass (FFM) in overweight men or women during weight loss. Journals published between 1966 and 1993 were searched by MEDLINE and by handsearch to obtain all reports on human subjects in which the effect of exercise on body composition was studied in at least two concurrent treatment groups, of which at least one group did, and one group did not, undergo an exercise programme designed to promote fat loss. The relation between loss of weight, and loss of FFM, was examined by linear regression analysis among exercising and non-exercising groups of men or women. Twenty-eight publications reported results on 226 sedentary men in 13 groups, 233 exercising men in 14 groups, 199 sedentary women in 23 groups, and 258 exercising women in 28 groups. Aerobic exercise without dietary restriction among men caused a weight loss of 3 kg in 30 weeks compared with sedentary controls, and 1.4 kg in 12 weeks among women, but there was little effect on FFM. Resistance exercise had little effect on weight loss, but increased FFM by about 2 kg in men and 1 kg in women. Regression analysis shows that for a weight loss of 10 kg by diet alone the expected loss of FFM is 2.9 kg in men and 2.2 kg in women. When similar weight loss is achieved by exercise combined with dietary restriction the expected loss of FFM is reduced to 1.7 kg in men, and women. It is probable that the FFM conserved by exercise during weight loss contains more water and potassium than average FFM. The subjects studied were not severely obese. Aerobic exercise causes a modest loss in weight without dieting. Exercise provides some conservation of FFM during weight loss by dieting, probably in part by maintaining glycogen and water.
... There are a large number of systematic reviews and metaanalyses directly comparing the effects of diet alone or in conjunction with exercise on the improvement of health outcomes [20][21][22][23][24]. However, to the best of our knowledge, only one systematic review compares energy-restricted diets and combined energy-restricted diet and exercise on HRQOL [25]; and no meta-analysis was performed. ...
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Background and aim Obesity and related co-morbidities lead to a decrease in health-related quality of life (HRQOL) and mood. Lifestyle strategies may improve these outcomes. However, the efficacy of exercise in conjunction with a weight-loss diet on HRQOL and mood is unclear. The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) was to examine whether the addition of exercise to energy-restricted dietary programs improves HRQOL and mood status when compared with energy-restricted diets alone in overweight and obese adults. Methods Eligible RCTs were identified by searching PubMed/MEDLINE, EMBASE, ISI (Web of sciences), Scopus, and Google Scholar up to April 2021. Summary effects were derived using a random-effects model. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. Results The meta-analysis revealed that an energy-restricted diet plus exercise compared with an energy-restricted diet alone had no significant effects on depression (n = 6, hedges’g = − 0.04, 95% CI: − 0.28,0.20), MOS 36-Item Short-Form Health Survey (SF-36)-physical component summary scores (n = 8, weighted mean difference (WMD) = 1.51, 95% CI: − 0.16, 3.18), SF36-mental component summary scores (n = 7, WMD = 0.64, 95% CI: − 1.00, 2.28), and HRQOL disease-specific questionnaire scores (n = 5, hedges’g = 0.16, 95% CI: − 0.09, 0.40). The GRADE revealed that the quality of evidence was low for disease-specific HRQOL scores, and depression status; and high for physical and mental health assessed by SF-36. Conclusion In our sample of overweight and obese adults, no beneficial effect of adding exercise to an energy-restricted diet was found in terms of HRQOL and Depression.
... The majority of these studies, and the present study, have not included a dietary co-intervention to support HIIT. This is notable because it is generally accepted that dietary cointerventions are needed in order for exercise to result in meaningful changes in fat mass in overweight and obese adults (Donnelly & Smith, 2005;Garrow & Summerbell, 1995;Miller et al., 1997). Additionally, analysis of fasted serum samples in the present study demonstrated the absence of an effect of BWHIIT on blood-based markers of metabolic health. ...
Article
Purpose: The effects of 8 weeks of bodyweight exercise-based, high-intensity interval training (BWHIIT) on body composition and blood-based markers of metabolic health were investigated in overweight and obese, sedentary young men. Methods: In a parallel group, PRE-POST design, n = 30 men (age, 25.7 ± 4.3 y; body mass index, 27.7 ± 2.1 kg m−2; 26.1 ± 5.2% body fat) were randomized to BWHIIT (n = 20) or a control group (CON; n = 10). BWHIIT consisted of supervised, group-based training sessions (~30 minutes) performed 3 times weekly. Each session consisted of 6 high-intensity bodyweight-based exercises, with each exercise being performed for 4 minutes in the manner of 8 sets of 20 seconds of exercise, 10 seconds of rest. Prior to commencing training (PRE), and 36 h after the final training session (POST), an overnight fasted blood sample was drawn, and body composition was assessed by dual-energy X-ray absorptiometry. Eighteen participants completed the intervention (CON, n = 9; BWHIIT, n = 9). Results: Lean body mass (LBM) was increased at POST in BWHIIT compared to CON (P = .011, η2p = .359), with the mean (95% confidence limits) increase in LBM from PRE to POST within BWHIIT being 1.23 (0.55, 1.92) kg. Body mass and fat mass were unchanged in both groups from PRE to POST. BWHIIT had no effect on serum concentrations of total cholesterol, HDL-C, LDL-C, triglycerides, NEFA, hsCRP, or glucose. Conclusion: Eight weeks of bodyweight exercise-based high intensity interval training by overweight and obese sedentary young men increased LBM by ~2%, but fat mass and blood-based markers of metabolic health were unchanged.
... 44 The contribution of lean mass remains relatively constant across a wide range of weight losses. 45 In a randomized controlled trial, participants with obesity (BMI 37.8 kg/m 2 ) lost 5% of their body weight by calorie restriction over 3 months-4 months and had their body composition measured by DXA. 38 These participants lost 5.5 kg of weight, of which 4.25 kg was fat mass corresponding to 79% of the total weight loss, and 1.25 kg was lean mass corresponding to 21% of the total weight loss ( Figure 2). ...
Article
Calorie restriction regimens are popular for their purported health-promoting effects. However, it is unclear whether chronic reduction in energy intake and subsequent weight loss have beneficial effects in the absence of obesity. To this end, the results of studies that examined the effects of the same diet-induced weight loss in individuals with and without obesity were reviewed. The contribution of lean mass to the total amount of weight lost is greater in participants without obesity than in those with obesity, but the reductions in resting, nonresting, and total energy expenditure are of similar magnitude. Both in the presence as well as in the absence of obesity, weight loss decreases visceral adipose tissue and liver fat, increases insulin sensitivity in skeletal muscle (insulin-mediated whole-body glucose disposal rate) and in adipose tissue (meal-induced or insulin-induced suppression of plasma free fatty acid concentration), and augments insulin clearance rate, without affecting pancreatic insulin secretion. These effects are of similar magnitude in participants with and without obesity and result in reductions in fasting plasma glucose and insulin concentrations. These data suggest that the same degree of calorie restriction and the same amount of weight loss have multiple beneficial effects on health outcomes in individuals without obesity, similar to those observed in individuals with obesity.
... As described above in the section on sex differences, higher baseline fat mass can act as a "buffer" against energy deficit, as it provides a source of energy that can be liberated during times of scarcity to protect other tissues (Forbes, 2000). This "protein sparing" effect of body fat (Elia et al., 1999), whereby individuals with increased body fat lose relatively less muscle mass than their leaner counterparts, has been documented in several studies (Garrow & Summerbell, 1995;Friedl et al., 1997;Forbes, 2000;Weinheimer et al., 2010;Ocobock, 2017;Pons et al., 2018). It is, however, important to consider that energy storage is just one function of body fat -this tissue also contributes to multiple other essential physiological functions, including insulation, organ protection, and regulation of a myriad of metabolic processes (Frayn et al., 2003;Kershaw & Flier, 2004). ...
Article
Energy is a finite resource that is competitively distributed among the body’s systems and biological processes. During times of scarcity, energetic “trade-offs” may arise if less energy is available than is required to optimally sustain all systems. More immediately essential functions are predicted to be prioritized, even if this necessitates the diversion of energy away from – and potential downregulation of – others. These concepts are encompassed within life history theory, an evolutionary framework with considerable potential to enhance understanding of the evolved biological response to periods of energy deficiency. Skeletal muscle is a particularly interesting tissue to investigate from this perspective, given that it is one of the largest and most energetically costly tissues within the body. It is also highly plastic, responsive to a broad range of stimuli, and contributes to many essential bodily functions, e.g., mechanical, regulatory and storage. These functions may be traded off against each other during periods of energy deficiency, with the nature of the trade-off’s dependent on the characteristics of the individual and the circumstances within which the deficit occurs. In this review, we consider the skeletal muscle response to periods of energy deficiency from a life history perspective, along with how this response may be influenced by factors including sex, age, body composition, training and nutritional status.
... Although weight change was not a primary outcome measure in the current study, it is still important to note that, on average, EX lost 1.3 kg more than CON, which was not statistically significant. Previous research indicates that the effect of exercise on body weight is typically only 2-3 kg (46). Moreover, based on the energy expenditure of the objectively confirmed exercise in the current study, a mean weight loss of 2.0 kg would have been expected, suggesting that a small degree of energy compensation may have occurred in response to the exercise training. ...
Article
Purpose: This efficacy trial tests the hypothesis that exercise training favorably affects hedonic eating (i.e., overeating, stress-induced overeating, disinhibited eating, eating when tempted), in a sample of women who are overweight or obese. Methods: Participants were inactive at baseline, self-identified as "stress eaters," and were randomized to 12 wk of moderate-intensity exercise training (EX; combination of supervised and objectively confirmed unsupervised sessions) or to a no-exercise control condition (CON). EX participants were given an exercise goal of 200 min·wk-1. No dietary instructions or weight control strategies were provided. Assessments occurred at baseline and 12 wk. Overeating episodes, stress-induced overeating, and dietary temptations were measured over 14 d at each assessment using ecological momentary assessment. Disinhibition and dietary restraint were assessed via a questionnaire. Results: Forty-nine participants (age, 40.4 ± 10.8 yr; body mass index, 32.4 ± 4.1 kg·m-2) enrolled, and 39 completed this study. Adherence to the exercise intervention was high (99.4% of all prescribed exercise). At week 12, the proportion of eating episodes that were characterized as overeating episodes was lower in EX versus CON (21.98% in EX vs 26.62% in control; P = 0.001). Disinhibition decreased in EX but not in CON (P = 0.02) and was driven by internal factors. There was a trend such that CON was more likely to give into dietary temptations (P = 0.08). Stress-induced overeating was low and did not differ between conditions (P = 0.61). Conclusions: Exercise training reduced the likelihood of overeating and eating in response to internal cues in women who self-identified as stress eaters. This may be one pathway by which exercise affects body weight.
... They were looking for easy and effective diets that did not limit caloric intake and improved insulin sensitivity and leptin sensitivity in individuals with metabolic disorders including diabetes and metabolic syndrome. Previous studies of exercise or low carbohydrate ketogenic diets reported reduced weight, improved body composition, and physical outcomes, respectively [10,11]. However, several previous studies reported controversial findings and there were several debates about high fat intake [12,13]. ...
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Abstract: (1) Background: The purpose of this meta-analysis was to investigate the effects of combined exercise and low carbohydrate ketogenic diet interventions (CELCKD) for overweight and obese individuals. (2) Methods: Relevant studies were searched by using the MEDLINE and EMBASE databases up to October 2020. Study Inclusion and Exclusion Criteria: Inclusion criteria were reporting effects of the CELCKD for overweight and obese individuals from randomized controlled trials. Studies that did not match the inclusion criteria were excluded. The methods for CELCKD and outcomes of selected studies were extracted. The effect sizes for interventions that included ardiorespiratory fitness, body composition, fasting glucose, and lipid profiles were calculated by using the standardized mean difference statistic. (3) Results: A total of seven studies and 278 overweight and obese individuals were included. The average intervention of selected studies consisted of moderate to vigorous intensity, 4 times per week for 9.2 weeks. Participating in CELCKD interventions was decreased triglycerides (d = 􀀀0.34, CI; 􀀀0.68–􀀀0.01, p = 0.04) and waist circumference (d = 􀀀0.74, 95% confidence interval [CI]; 􀀀1.28–􀀀1.20, p = 0.01), while cardiovascular fitness, body composition, fasting glucose, total cholesterol, high density lipoprotein (HDL) cholesterol, and low density lipoprotein (LDL) cholesterol were not statistically different after the interventions. No adverse side effects were reported. (4) Conclusions: Participation in interventions by overweight and obese individuals had beneficial effects including decreased waist circumference and triglycerides. Longer term intervention studies with homogenous control groups may be needed.
Chapter
Exercise/physical activity (PA) can reduce susceptibility to many chronic conditions including obesity and associated metabolic disorders (type 2 diabetes, nonalcoholic fatty liver disease), cardiovascular disease, and certain cancers with benefits on cognition, mood, and general well‐being. The premise that exercise/PA is associated with significant weight loss dates is linked with an observation in 1958 that adipose tissue is energy‐dense containing 3500 calories/pound. To achieve energy balance, EI must equal EE. Strategies to combat excess weight gain, aside from the obvious reduction of EI, would also include increased EE through PA. The chapter examines the relationship between weight loss and improvements in weight‐related comorbidities. Multiple short bouts of walking have been assessed as a tool for weight loss modality on the assumption that multiple SB of walking may achieve more weight loss or be easier to finish than one LB of walking.
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To systematically review and analyze the effects of resistance-based exercise programs on body composition, regional adiposity, and body weight in individuals with overweight/obesity across the lifespan. Using PRISMA guidelines, randomized controlled trials were searched in nine electronic databases up to December 2020. Meta-analyses were performed using random-effects model. One-hundred sixteen articles describing 114 trials (n = 4184 participants) were included. Interventions involving resistance training and caloric restriction were the most effective for reducing body fat percentage (ES = -3.8%, 95% CI: -4.7 to -2.9%, p < 0.001) and whole-body fat mass (ES = -5.3 kg, 95% CI: -7.2 to -3.5 kg, p < 0.001) compared with groups without intervention. Significant results were also observed following combined resistance and aerobic exercise (ES = -2.3% and -1.4 kg, p < 0.001) and resistance training alone (ES = -1.6% and -1.0 kg, p < 0.001) compared with no training controls. Resistance training alone was the most effective for increasing lean mass compared with no training controls (ES = 0.8 kg, 95% CI: 0.6 to 1.0 kg, p < 0.001), whereas lean mass was maintained following interventions involving resistance training and caloric restriction (ES = ~-0.3 kg, p = 0.550-0.727). Results were consistently observed across age and sex groups (p = 0.001-0.011). Reductions in regional adiposity and body weight measures were also observed following combined resistance and aerobic exercise and programs including caloric restriction (p < 0.001). In conclusion, this study provides evidence that resistance-based exercise programs are effective and should be considered within any multicomponent therapy program when caloric restriction is utilized in individuals with overweight or obesity.
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Background Exercise and weight loss diets are two independent non-pharmaceutical strategies used to improve several aspects of body composition and health. We plan to systematically review controlled clinical trials investigating weight loss diets alone compared to weight loss diets in conjunction with exercise on energy intake, body weight, body composition, cardiometabolic risk factors, sex hormones, and mental health. Methods and analysis PubMed/MEDLINE, EMBASE, ISI (Web of Science), Scopus, and Google Scholar will be searched to retrieve potential controlled clinical trials investigating the effects of exercise in conjunction with weight loss diets compared with weight loss diets alone on energy intake, body weight and composition (fat mass, fat-free mass), anthropometrics (waist circumference), cardiometabolic markers, sex hormones [testosterone, estradiol, and sex hormone binding globulin (SHBG)], liver and kidney enzymes (alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), uric acid, blood urea nitrogen (BUN), glomerular filtration rate (GFR), quality of life, and depression in adults. The weighted mean difference (WMD) and its corresponding 95% confidence intervals (CIs) will be derived using random effects model. Several subgroup analyses based on follow-up duration, the health status of the participants, the diet used for weight loss, the exercise protocol, participants’ sex, and other possible variables will be conducted to explore possible sources of heterogeneity. Publication bias will be explored by inspecting funnel plots and by conducting asymmetry tests. Overall quality of the evidence will be assessed by using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool. Discussion We envisage that this systematic review and meta-analysis will provide valuable information regarding the effectiveness of adding exercise to weight loss diets. No primary data is going to be collected; therefore, ethical approval is not required. The resulting manuscripts will be disseminated in peer-reviewed journals and at international and national conferences. Systematic review registration The study protocol is registered in the International Prospective Register of Systematic Reviews (PROSPERO, Registration ID: CRD42020173434).
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Ovulation and fertility can be improved by weight loss in obese women with Polycystic Ovarian Syndrome (PCOS). The aim of this study was to investigate the effectiveness of a twelve-week supervised exercise program in combination with dietary restrictions for obese women with PCOS. The study is a quasi-experimental research and used an experimental pre- and post-test design. Fifteen women recruited from Fertility Clinic, Jessops Hospital for Women, Sheffield took part in this study. Respiratory exchange ratio (RER), heart rate, perceived exertion (RPE), and Houston non-exercise activity code were recorded. Height, weight, and body girth measurements were taken to calculate body mass index, fat percentage, and lean body weight. The intervention group lost an average of 3.1 kg and gained 3.45 kg of lean body weight. Loss of fat percentage was 12.1%. No significant difference was found in the control group. The RER and heart rate value decreased for the same workload in the intervention group, indicating higher tolerance towards exercise intensity. However, the changes for both groups were not significant. The average group compliance rate was 53% (at least two sessions per week). Bearing in mind the small sample size (n=4) for control, the improvement in fitness, significant weight loss, and body composition change (increase in fat-free mass) was achieved in this study. Twelve weeks of exercise, combined with dietary advice, were sufficient to benefit PCOS obese women. The research has achieved a commendable weight-loss objective and has demonstrated increases in standards of fitness among obese women.
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