Body fat loss and compensatory mechanisms in response to different doses of aerobic exercise—a randomized controlled trial in overweight sedentary males

Abstract

A diet-induced negative energy balance triggers compensatory mechanisms, e.g., lower metabolic rate and increased appetite. However, knowledge about potential compensatory mechanisms triggered by increased aerobic exercise is limited. A randomized controlled trial was performed in healthy, sedentary, moderately overweight young men to examine the effects of increasing doses of aerobic exercise on body composition, accumulated energy balance, and the degree of compensation. Eighteen participants were randomized to a continuous sedentary control group, 21 to a moderate-exercise (MOD; 300 kcal/day), and 22 to a high-exercise (HIGH; 600 kcal/day) group for 13 wk, corresponding to ϳ30 and 60 min of daily aerobic exercise, respectively. Body weight (MOD: Ϫ3.6 kg, P Ͻ 0.001; HIGH: Ϫ2.7 kg, P ϭ 0.01) and fat mass (MOD: Ϫ4.0 kg, P Ͻ 0.001 and HIGH: Ϫ3.8 kg, P Ͻ 0.001) decreased similarly in both exercise groups. Although the exercise-induced energy expenditure in HIGH was twice that of MOD, the resulting accumulated energy balance, calculated from changes in body composition, was not different (MOD: Ϫ39.6 Mcal, HIGH: Ϫ34.3 Mcal, not significant). Energy balance was 83% more negative than expected in MOD, while it was 20% less negative than expected in HIGH. No statistically significant changes were found in energy intake or nonexercise physical activity that could explain the different compensatory responses associated with 30 vs. 60 min of daily aerobic exercise. In conclusion, a similar body fat loss was obtained regardless of exercise dose. A moderate dose of exercise induced a markedly greater than expected negative energy balance, while a higher dose induced a small but quantifiable degree of compensation.exercise; body weight regulation; compensatory mechanisms; energy balance ALTHOUGH A MODERN SEDENTARY lifestyle along with overeating has been put forward as "Big Two" factors in the etiology of obesity (3,10,29), the outcomes of structured exercise programs designed to promote weight loss are often modest (42,58). This has led to the general (mis)conception that exercise, in itself, is a poor weight management strategy (20,42,49). Apart from a potential lack of compliance, the discrepancy between predicted and observed weight loss is likely due to a combination of physiological and behavioral compensatory changes affecting energy balance. These compensatory changes cause the accumulated energy balance during an exercise intervention to be less negative than would be theoretically predicted from the exercise-induced energy expenditure (ExEE), i.e., the total amount of energy expenditure that is caused by the exercise intervention (12,32,34).Body energy stores are protected against long-term negative energy balance resulting from caloric restriction by a greater than predicted reduction in resting energy expenditure (REE) (28), a decrease in nonexercise activity thermogenesis (NEAT) (40,45), an increase in the metabolic efficiency of physical activity (16,35), and an increase in hedonic (21) and hormonal mediators o...

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“…Kromhout et al (2001) observed that physical activity was negatively associated with BMI and body fat, and suggested that regular exercise could decrease body weight and body fat significantly. Meanwhile, it was reported that moderate intensity exercise is more effective in increasing fat oxidation and burns more body fat than high intensity exercise does (Achten & Jeukendrup, 2004;Romijn et al, 1993;Rosenkilde et al, 2012). However, our findings showed that jogging exercise with moderate exercise intensity at 55% to 70% of agepredicted HR max , 30 minutes per day, and 3 days per week for 8 weeks in J group did not affect the body weight and body fat.…”

“…However, our findings showed that jogging exercise with moderate exercise intensity at 55% to 70% of agepredicted HR max , 30 minutes per day, and 3 days per week for 8 weeks in J group did not affect the body weight and body fat. Rosenkilde et al (2012) and Romijn et al (1993) mentioned that increasing the dose of exercise or intensity is not always effective to lose weight and body fat. Even though estimated calorie burn during exercise was approximately 4 104 cal, which correspond to 456 g of body fat during the 8 weeks of study period, the observation of jogging exercise alone did not affect body fat in the present study might be due to prescribed exercise or duration of the present study was not long enough.…”

Translational Science: How experimental research has contributed to the understanding of spontaneous Physical Activity and Energy Homeostasis

“…They speculate this greaterthan-expected energy expenditure could have been caused by an increase in SPA. In sharp contrast, the group performing the higher-dose exercise accumulated a negative balance 20% less effective than expected 38 . Thus, it is clear that when exercise is used as a tool to promote negative energy balance, the compensatory behavior it triggers must be taken into account.…”

“…Accordingly, Morio et al 37 found that a progressive endurance training in elderly individuals did not change their total daily energy expenditure due to a compensatory decrease in free-living activities. On the other hand, Rosenkilde et al 38 showed that moderate exercise accumulated a negative balance 80% greater than expected, without increasing energy intake. They speculate this greaterthan-expected energy expenditure could have been caused by an increase in SPA.…”

Energy Expenditure Responses To Exercise Training In Older Women

“…NEAT is defined as the EE associated with all activities of daily living, such as fidgeting, maintaining posture, and ambulation, other than purposeful exercise (Levine and Kotz 2005;Melanson et al 2013). Most studies in young to middle-aged adults did not observe reductions in NEAT (McLaughlin et al 2006;Hollowell et al 2009;Turner et al 2010;Rangan et al 2011;Willis et al 2014) or nonexercise physical activity (Meijer et al 1991;Van Etten et al 1997;Lynch et al 2009;Rosenkilde et al 2012;Willis et al 2014). However, the findings in older adults (mean age >57 years) are mixed.…”