Physical Activity, Sedentary Behaviour, and Obesity

chapter 6. Physical activity, sedentary behaviour, and obesity

Michael Leitzmann

Insufficient levels of daily physical utes per week of moderate-intensity a particular threshold. Despite this activity play a potentially major role in physical activity for overweight or issue, some have operationalized contributing to the obesity epidemic obese adults to improve their health, the definition of weight maintenance that currently affects both developed and 200–300 minutes per week for as a change of ≤ 5 lb (≤ 2.3 kg) [4] and developing countries. Therefore, long-term weight loss [1]. Moder- or < 3% of body weight [5], with a physical activity has become a vital ate-intensity activities are those that weight change of > 5% considered part of public health strategies for require 3–6 times as much energy as to be clinically significant [5]. prevention of weight gain, for weight sitting quietly. In 2002, the Institute of This chapter discusses whether loss, and for prevention of weight Medicine of the National Academies physical activity is effective for pre- regain after weight loss. In fact, vir- recommended 60 minutes per day of vention of weight gain, for weight tually all public health agencies and moderate-intensity physical activity loss, and for prevention of weight re- scientific organizations recommend for prevention of unhealthful weight gain after weight loss. This chapter physical activity as part of weight gain [2]. In 2003, the International focuses primarily on adults. management, including but not limit- Association for the Study of Obesity ed to the World Health Organization advocated 40–50 minutes per day Physical activity and prevention (WHO), the United States Centers of moderate-intensity physical ac- of weight gain for Disease Control and Prevention tivity for prevention of obesity, and (CDC), the National Heart, Lung, and 60–90 minutes per day for prevention Primary prevention of obesity begins

Blood Institute, the American Heart of weight regain in formerly obese with weight maintenance, not weight 6 CHAPTER Association, the American College individuals [3]. reduction. Long-term observation- of Sports Medicine (ACSM), and the Setting definitions for clinical- al studies of physical activity in re- World Obesity Federation, as well ly significant weight loss has been lation to weight maintenance fairly as several national and regional challenging, in part because health consistently show a relationship guidelines. gains related to weight maintenance between the two. For example, the In 2001, the ACSM issued guide- or weight loss probably operate under prospective Harvard cohorts showed lines recommending at least 150 min- a continuum and are not based on that women and men who reported

Chapter 6. Physical activity, sedentary behaviour, and obesity 43 increasing their recreational activity the effect of isolated physical activi- body mass, and therefore it leads to a levels by 23.2 metabolic equivalent ty on weight loss among overweight more desirable effect on overall body (MET)-hours per week (top quin- and obese individuals from random- composition [12]. tile) gained 1.76 lb less (0.8 kg less) ized clinical trials and reported that Moreover, physical activity of within the next 4 years of follow-up 120–240 minutes per week of aero- high intensity leads to more pro- than those who decreased their ac- bic exercise at intensities of 40–85% nounced weight loss than physical tivity levels by 16.3 MET-hours per of maximum heart rate were relat- activity of lower intensity. This is in- week (bottom quintile) [6]. One MET ed to weighted mean differences dicated by pooled data on a compar- is defined as the ratio of the energy in weight of −1.6 kg (95% confidence ison of high-intensity versus low-in- consumed during a specific activity interval [CI], −1.64 to −1.56 kg) for tensity exercise without changes in to the energy consumed while sitting 6-month programmes and −1.7 kg diet during 3.5–12-month periods −1 −1 quietly (3.5 mL O2 kg min ). Sim- (95% CI,−2.29 to −1.11 kg) for 12-month in 317 subjects from four trials, in ilarly, the 15-year Coronary Artery programmes. The authors concluded which the high-intensity-exercise Risk Development in Young Adults that isolated aerobic exercise is not group showed a reduction in weight (CARDIA) Study reported that each an effective weight-loss therapy but of −1.5 kg (95% CI, −2.3 to −0.7 kg) 0.5 hour per day of walking, the most may be effective in conjunction with compared with the low-intensity- popular type of recreational activity diets [10]. exercise group [11]. among adults, was associated with Most recommendations from pub- According to the 2009 ACSM po- 0.15 kg/year less weight gain in men lic health organizations and govern- sition paper, physical activity demon- and 0.29 kg/year less weight gain in ment agencies use both physical ac- strates a dose–response relationship women, with stronger associations tivity and dietary energy restriction for with weight loss, such that < 150 min- noted among those with a larger weight loss. Weight-loss programmes utes per week of moderate-intensi- baseline weight [7]. Taken togeth- vary considerably with respect to the ty physical activity yields minimal er, these long-term epidemiological amount of physical activity used and weight loss, > 150 minutes per week investigations indicate that moder- the level of energy restriction imposed, of moderate-intensity physical activ- ate-intensity physical activity is as- with a greater energy deficit yielding ity results in weight loss of 2–3 kg, sociated with prevention of weight a more pronounced weight loss. Ev- and 225–420 minutes per week of gain. A 2009 position paper from idence suggests that dietary energy moderate-intensity physical activity the ACSM stated that 150–250 min- restriction combined with physical leads to weight loss of 5–7.5 kg [8]. utes per week of moderate-intensity activity results in greater weight loss In addition to the effect of physical physical activity is effective to prevent than dietary energy restriction alone. activity on weight loss, regular exer- weight gain [8]. For example, a Cochrane review cise yields numerous health benefits involving 1049 subjects from 14 trials independent of weight loss, such as Physical activity and weight loss with follow-up of 3–12 months com- improvements in insulin action, blood pared exercise plus diet versus diet lipids, endothelial function, haemo- A negative energy balance brought alone and reported a weight loss of static factors, and blood pressure about by physical activity will lead to −1.1 kg (95% CI, −1.5 to −0.6 kg) in [13]. weight loss, with a greater negative the exercise-plus-diet group versus energy balance resulting in a more the diet-only group [11]. Similarly, Physical activity and prevention pronounced weight loss. Directed pooling the data from 452 subjects of weight regain after weight research on the long-term effect of from five trials yielded a reduction in loss physical activity on weight loss has body mass index (BMI) of −0.4 kg/ been sparse. A 12-month random- m2 (95% CI, −0.7 to −0.1 kg/m2) in Most people are able to lose weight ized controlled trial found a cumu- the exercise-plus-diet group versus but have considerable difficulty lative weight loss of 1.8 kg in men the diet-only group [11]. Physical ac- maintaining weight loss. Physical and 1.4 kg in women for those engag- tivity and dietary energy restriction activity is widely endorsed as being ing in moderate to vigorous activity yield comparable weight loss if they indispensable for long-term weight for 60 minutes per day, 6 days per offer similar amounts of negative maintenance [1] and is frequently week [9]. By comparison, sedentary energy balance. Importantly, energy referred to as a stable predictor of controls gained 0.1 kg (men) and 0.7 kg restriction combined with exercise weight maintenance after weight loss (women) during that period. A recent training is more effective than en- [14]. The evidence for maintenance systematic review and meta-analysis ergy restriction alone for increasing of weight loss is far less abundant examined the available evidence on loss of fat mass and preserving lean than that for initiation of weight loss.

44 A recent systematic review and Intervention studies have consis- Few studies have examined the meta-analysis of randomized con- tently found no effect of resistance effects of resistance exercise on trolled trials on long-term mainte- exercise on reducing body weight [8] prevention of weight gain. One ran- nance of weight loss reported that the or visceral adipose tissue [18]. The domized trial assessed the efficacy combination of physical activity and combination of resistance and aero- of a 2-year strength programme in dietary energy restriction resulted bic exercise may enhance loss of fat 164 overweight and obese pre- in a difference of −1.56 kg (95% CI, mass compared with resistance ex- menopausal women and reported −2.27 to −0.86 kg) in weight regain ercise alone. A recent meta-analysis decreased percentage of body fat compared with controls at 12 months of 15 trials with 741 participants com- (2-year change of −3.68% ± 0.99% [15]. There was no evidence of ef- pared the effect of 2.5–6 months of vs −0.14% ± 1.04% in controls) and fectiveness for interventions involv- aerobic training and resistance train- attenuated intra-abdominal fat (2- ing physical activity only. An earlier ing on weight loss in overweight and year change of 7.05% ± 5.07% vs systematic review that also included obese subjects and reported that com- 21.36% ± 5.34% in controls) [20]. observational studies reported that pared with resistance training, aerobic These results are relevant to obe- individuals who engaged in physi- training produced greater decreases sity prevention programmes be- cal activity experienced less weight in body weight (mean difference [MD], cause most weight gain in adults regain than their sedentary counter- −1.15 kg; 95% CI, −2.23 to −0.07 kg), is assumed to be fat, including ab- parts, but confounding by a healthy waist circumference (MD, −1.10 cm; dominal fat. lifestyle or reverse causation by bet- 95% CI, −1.85 to −0.36 cm), and fat Data about the influence of re- ter exercise adherence among those mass (MD, −1.14 kg; 95% CI, −1.83 sistance training on prevention of with less weight regain could not be to −1.45 kg) [19]. However, resistance weight regain after weight loss are ruled out [16]. Taken together, find- training was more effective than aer- also sparse. One trial assigned 90 ings from observational studies and obic training in increasing lean body middle-aged, obese, physically inac- controlled trials show inconsistent mass (MD, 1.26 kg; 95% CI, 0.71 to tive men to a 2-month very-low-en- results, and the volume of physical 1.81 kg). Moreover, compared with ergy diet followed by randomization activity needed to prevent weight re- resistance training alone, the com- into 6 months of resistance training, gain after weight loss remains poor- bination of aerobic and resistance walking, or no exercise [21]. The re- ly defined. Despite these uncertain- training yielded more pronounced sults showed that resistance training ties, the 2009 ACSM position paper reductions in body weight (MD, initially attenuated the regain of fat suggested that weight maintenance −2.03 kg; 95% CI, −2.94 to −1.12 kg), mass during the exercise programme. after weight loss is improved with waist circumference (MD, −1.57 cm; However, there were no differences > 250 minutes of physical activity 95% CI, −2.38 to −0.75 cm), and fat in weight regain between the groups per week [8]. mass (MD, −1.88 kg; 95% CI, −2.67 after 23 months of follow-up, which to −1.08 kg), whereas the combina- was explained by poor long-term ad- Resistance training tion of aerobic and resistance training herence to the prescribed exercise generated a greater increase in lean programme [21]. Resistance training has not been con- body mass (MD, 0.90 kg; 95% CI, sidered a major contributor to weight 0.31 to 1.48 kg) than aerobic train- Sedentary behaviour loss, because the energy expenditure ing alone [19]. These pooled findings associated with weight training is gen- on the combination of aerobic and In recent years, physical activity re- erally less than that associated with a resistance training need to be in- search has expanded its focus to typical aerobic exercise session of the terpreted with caution, because the include the potentially detrimental same duration. In addition, resistance total volume of exercise prescribed effects of sedentary behaviour on exercise increases fat-free mass, po- in some of the combination training energy balance. The prevalence of tentially leading to a net gain in body groups was greater than the respec- sedentary behaviour has increased

weight. However, resistance exercise tive volumes in the aerobic training markedly in recent years, with objec- 6 CHAPTER is associated with acute stimulation of and resistance training groups. Not- tively assessed measures showing metabolic rate and fat oxidation, and withstanding the potential confound- that adults spend 50–60% of their it enhances total energy expenditure ing effects of training volume, these day sedentary [22]. Sedentary be- because of increased muscle mass; data suggest that the combination of haviour occurs in various domains this provides some rationale for aerobic and resistance training may of life, including television or video examining its relationship to weight be the most efficacious exercise train- viewing, computer use, reading, or loss [17]. ing modality for weight loss. sitting at a desk, at a counter, or in

Chapter 6. Physical activity, sedentary behaviour, and obesity 45 a bus, car, or train. Prolonged time 5 years of follow-up [25]. Compared Physical activity and appetite spent sedentary decreases energy with those who reported no computer regulation expenditure and displaces light-in- gaming, women with a high volume of tensity physical activities, potentially computer gaming (> 2 hours per day) At habitually high levels of energy leading to weight gain over time. Al- had an odds ratio of developing over- expenditure, energy intake appears though sedentary behaviour shows weight of 3.0 (95% CI, 1.29–6.83) af- to be matched to energy expenditure, an inverse relationship with light-inter adjustment for age, occupation, resulting in maintenance of energy tensity physical activity, it can be social support, physical activity, balance. However, at low levels of conceptualized as a lifestyle factor sleep, and total computer use. No energy expenditure, homeostatic that can coexist with moderate to vig- statistically significant association regulation of appetite control is lost orous physical activity [23]. Current was noted among men (odds ratio, and fails to restrain appetite to the public health programmes to reduce 1.4; 95% CI, 0.77–2.66). In addition, low levels required to maintain en- obesity have focused largely on de- no statistically significant relation- ergy balance. There is evidence that creasing dietary energy intake and ships emerged between leisure-time enhanced appetite control with high increasing physical activity but have emailing/chatting and overweight in levels of energy expenditure oper- paid little attention to decreasing time either women or men. The findings ates through a mechanism involving spent sedentary. from this small cohort study suggest augmented insulin and leptin sensi- The Nurses’ Health Study exam- that sedentary behaviour that occurs tivity brought about by decreased fat ined the association between seden- during computer gaming is a potential mass [27]. tary behaviours, in particular televi- risk factor for overweight, but further sion viewing, and risk of obesity [24]. research is needed. Conclusions The findings showed that time spent Sedentary behaviour is also an watching television was positively re- independent risk factor for obesity Moderate-intensity physical activity lated to risk of obesity. Specifically, in children and adolescents. In fact, performed for 150–250 minutes per each increment of 2 hours per day preventing childhood obesity has week appears to prevent weight gain in television watching was associ- been described as the most favour- and may produce modest weight ated with a 23% (95% CI, 17–30%) able approach to reversing the glob- loss in adults. Greater amounts of increase in obesity after adjusting for al obesity epidemic. A recent me- moderate-intensity physical activity age, smoking, diet, and physical ac- ta-analysis of 25 studies compared (> 250 minutes per week) are re- tivity. Also, each increment of 2 hours three types of interventions with quired for weight maintenance after per day in sitting at work was asso- regard to their potential of reduc- weight loss. Resistance exercise ciated with a statistically non-signifi- ing BMI in children: (i) interventions does not appear to decrease body cant 5% (95% CI, 0–10%) increase aimed at decreasing sedentary be- weight or body fat, but it promotes in obesity. These results highlight haviours, (ii) interventions aimed at gain of lean body mass, and the the potential value of decreasing pro- decreasing sedentary behaviours in combination of resistance exercise longed television watching and other combination with promoting physical and aerobic exercise seems to be sedentary behaviours for preventing activity, and (iii) interventions aimed optimal for weight loss. Increased obesity in adults. at decreasing sedentary behaviours physical activity decreases levels Computer gaming and use of so- in combination with promoting phys- of risk factors for chronic diseases, cial media are additional important ical activity and improving dietary independent of its impact on regu- sources of time spent sedentary, habits [26]. The results indicated that lating body weight. Moreover, sed- particularly among young adults. A interventions aimed at decreasing entary behaviour is an independent prospective cohort study of 2593 sedentary behaviours had a signifi- risk factor for the development of young adults aged 20–24 years in cant effect on reducing BMI, and that overweight and obesity. Sweden examined the association effect sizes of multicomponent inter- between leisure-time computer use ventions did not differ significantly for gaming/emailing/chatting and from those of the single-component overweight development during interventions.

46 Key points • Insufficient physical activity is a potentially relevant determinant of the global obesity epidemic. • Moderate-intensity physical activity performed for 150–250 minutes per week appears to prevent weight gain and may produce modest weight loss in adults. • Greater volumes of moderate-intensity physical activity (> 250 minutes per week) are required for weight maintenance after weight loss. • Resistance exercise alone has little effect on reducing body weight or adipose tissue. • The combination of resistance exercise and aerobic exercise appears to be optimal for weight loss. • Physical activity has important health benefits independent of its effects on regulating body weight. • Time spent sedentary is a potentially significant risk factor for obesity.

Research needs • There is a need for observational research using objectively assessed energy intake and energy expenditure in relation to long-term prevention of weight gain in free-living populations. • Intervention studies on the long-term effect of physical activity on weight loss are needed. • Research is needed on the amounts and intensities of physical activity required for prevention of weight regain after weight loss. • The efficacy of combined aerobic and resistance physical activity modalities for weight control should be examined. • The potential of decreased time spent sedentary for preventing obesity should be evaluated. • The combined effects of physical activity and body composition on appetite regulation should be investigated.

References

1. Jakicic JM, Clark K, Coleman E, Donnel- 2. Panel on Macronutrients, Panel on the 3. Saris WH, Blair SN, van Baak MA, Eaton SB, ly JE, Foreyt J, Melanson E, et al.; American Definition of Dietary Fiber, Subcommittee Davies PS, Di Pietro L, et al. (2003). How much College of Sports Medicine (2001). American on Upper Reference Levels of Nutrients, physical activity is enough to prevent unhealthy College of Sports Medicine position stand. Ap- Subcommittee on Interpretation and Uses of weight gain? Outcome of the IASO 1st Stock propriate intervention strategies for weight loss Dietary Reference Intakes, and the Standing Conference and consensus statement. Obes

and prevention of weight regain for adults. Med Committee on the Scientific Evaluation of Rev. 4(2):101–14. http://dx.doi.org/10.1046/ 6 CHAPTER Sci Sports Exerc. 33(12):2145–56. http://dx. Dietary Reference Intakes, Food and Nutrition j.1467-789X.2003.00101.x PMID:12760445 doi.org/10.1097/00005768-200112000-00026 Board (2002). Dietary reference intakes PMID:11740312 for energy, carbohydrate, fiber, fat, fatty 4. St Jeor ST, Brunner RL, Harrington ME, acids, cholesterol, protein, and amino acids. Scott BJ, Daugherty SA, Cutter GR, et al. Washington (DC), USA: National Academies (1997). A classification system to evalu- Press. Available from: https://www.nap.edu/ ate weight maintainers, gainers, and los- catalog/10490/dietary-reference-intakes- ers. J Am Diet Assoc. 97(5):481–8. http:// for-energy-carbohydrate-fiber-fat-fatty- dx.doi.org/10.1016/S0002-8223(97)00126-0 acids-cholesterol-protein-and-amino-acids- PMID:9145085 macronutrients.

Chapter 6. Physical activity, sedentary behaviour, and obesity 47 5. Stevens J, Truesdale KP, McClain JE, Cai J 13. Gaesser GA, Angadi SS, Sawyer BJ 21. Borg P, Kukkonen-Harjula K, Fogelholm (2006). The definition of weight maintenance. (2011). Exercise and diet, independent of M, Pasanen M (2002). Effects of walking or re- Int J Obes (Lond). 30(3):391–9. http://dx.doi. weight loss, improve cardiometabolic risk sistance training on weight loss maintenance org/10.1038/sj.ijo.0803175 PMID:16302013 profile in overweight and obese individu- in obese, middle-aged men: a randomized trials. Phys Sportsmed. 39(2):87–97. http:// al. Int J Obes Relat Metab Disord. 26(5):676– 6. Mozaffarian D, Hao T, Rimm EB, Willett dx.doi.org/10.3810/psm.2011.05.1898 83. http://dx.doi.org/10.1038/sj.ijo.0801962 WC, Hu FB (2011). Changes in diet and life- PMID:21673488 PMID:12032753 style and long-term weight gain in women and men. N Engl J Med. 364(25):2392–404. 14. Tate DF, Jeffery RW, Sherwood NE, Wing 22. Matthews CE, Chen KY, Freedson PS, http://dx.doi.org/10.1056/NEJMoa1014296 RR (2007). Long-term weight losses associat- Buchowski MS, Beech BM, Pate RR, et al. PMID:21696306 ed with prescription of higher physical activity (2008). Amount of time spent in sedentary goals. Are higher levels of physical activity behaviors in the United States, 2003–2004. 7. Gordon-Larsen P, Hou N, Sidney S, protective against weight regain? Am J Clin Am J Epidemiol. 167(7):875–81. http://dx.doi. Sternfeld B, Lewis CE, Jacobs DR Jr, et Nutr. 85(4):954–9. PMID:17413092 org/10.1093/aje/kwm390 PMID:18303006 al. (2009). Fifteen-year longitudinal trends in walking patterns and their impact on 15. Dombrowski SU, Knittle K, Avenell A, 23. Healy GN, Wijndaele K, Dunstan DW, weight change. Am J Clin Nutr. 89(1):19–26. Araújo-Soares V, Sniehotta FF (2014). Long Shaw JE, Salmon J, Zimmet PZ, et al. (2008). http://dx.doi.org/10.3945/ajcn.2008.26147 term maintenance of weight loss with non-sur- Objectively measured sedentary time, physical PMID:19056560 gical interventions in obese adults: systematic activity, and metabolic risk: the Australian review and meta-analyses of randomised con- Diabetes, Obesity and Lifestyle Study 8. Donnelly JE, Blair SN, Jakicic JM, Manore trolled trials. BMJ. 348:g2646. http://dx.doi. (AusDiab). Diabetes Care. 31(2):369–71. http:// MM, Rankin JW, Smith BK; American Col- org/10.1136/bmj.g2646 PMID:25134100 dx.doi.org/10.2337/dc07-1795 PMID:18000181 lege of Sports Medicine (2009). American College of Sports Medicine Position Stand. 16. Fogelholm M, Kukkonen-Harjula K 24. Hu FB, Li TY, Colditz GA, Willett WC, Man- Appropriate physical activity intervention (2000). Does physical activity prevent son JE (2003). Television watching and other strategies for weight loss and prevention of weight gain–a systematic review. Obes Rev. sedentary behaviors in relation to risk of obesity weight regain for adults. Med Sci Sports Ex- 1(2):95 –111. http://dx.doi.org/10.1046/j.1467- and type 2 diabetes mellitus in women. JAMA. erc. 41(2):459–71. http://dx.doi.org/10.1249/ 789x.2000.00016.x PMID:12119991 289(14):1785–91. http://dx.doi.org/10.1001/ MSS.0b013e3181949333 PMID:19127177 jama.289.14.1785 PMID:12684356 17. Strasser B, Arvandi M, Siebert U (2012). 9. McTiernan A, Sorensen B, Irwin ML, Mor- Resistance training, visceral obesity and inflam- 25. Thomée S, Lissner L, Hagberg M, gan A, Yasui Y, Rudolph RE, et al. (2007). matory response: a review of the evidence. Obes Grimby-Ekman A (2015). Leisure time comput- Exercise effect on weight and body fat in Rev. 13(7):578–91. http://dx.doi.org/10.1111/ er use and overweight development in young men and women. Obesity (Silver Spring). j.1467-789X.2012.00988.x PMID:22385646 adults – a prospective study. BMC Public 15(6):1496–512. http://dx.doi.org/10.1038/ Health. 15(1):839. http://dx.doi.org/10.1186/ oby.2007.178 PMID:17557987 18. Ismail I, Keating SE, Baker MK, John- s12889-015-2131-5 PMID:26329006 son NA (2012). A systematic review and me- 10. Thorogood A, Mottillo S, Shimony A, Filion ta-analysis of the effect of aerobic vs. resist- 26. Liao Y, Liao J, Durand CP, Dunton GF KB, Joseph L, Genest J, et al. (2011). Isolated ance exercise training on visceral fat. Obes (2014). Which type of sedentary behaviour in- aerobic exercise and weight loss: a systematic Rev. 13(1):68–91. http://dx.doi.org/10.1111/ tervention is more effective at reducing body review and meta-analysis of randomized con- j.1467-789X.2011.00931.x PMID:21951360 mass index in children? A meta-analytic re- trolled trials. Am J Med. 124(8):747–55. http:// view. Obes Rev. 15(3):159–68. http://dx.doi. dx.doi.org/10.1016/j.amjmed.2011.02.037 19. Schwingshackl L, Dias S, Strasser B, Hoff- org/10.1111/obr.12112 PMID:24588966 PMID:21787904 mann G (2013). Impact of different training modalities on anthropometric and metabolic 27. Blundell JE, Gibbons C, Caudwell P, Finlay- 11. Shaw K, Gennat H, O’Rourke P, Del Mar characteristics in overweight/obese sub- son G, Hopkins M (2015). Appetite control and C (2006). Exercise for overweight or obesity. jects: a systematic review and network me- energy balance: impact of exercise. Obes Rev. Cochrane Database Syst Rev. (4):CD003817. ta-analysis. PLoS One. 8(12):e82853. http:// 16(Suppl 1):67–76. http://dx.doi.org/10.1111/ PMID:17054187 dx.doi.org/10.1371/journal.pone.0082853 obr.12257 PMID:25614205 PMID:24358230 12. Miller CT, Fraser SF, Levinger I, Straznicky NE, Dixon JB, Reynolds J, et al. (2013). The 20. Schmitz KH, Hannan PJ, Stovitz SD, Bry- effects of exercise training in addition to an CJ, Warren M, Jensen MD (2007). Strength energy restriction on functional capacities training and adiposity in premenopausal wom- and body composition in obese adults during en: strong, healthy, and empowered study. Am weight loss: a systematic review. PLoS One. J Clin Nutr. 86(3):566–72. PMID:17823418 8(11):e81692. http://dx.doi.org/10.1371/journal. pone.0081692 PMID:24409219