Aerobic exercise alone results in clinically significant weight loss for men and women: Midwest exercise trial 2

Abstract

Exercise is recommended by public health agencies for weight management; however, the role of exercise is generally considered secondary to energy restriction. Few studies exist that have verified completion of exercise, measured the energy expenditure of exercise, and prescribed exercise with equivalent energy expenditure across individuals and genders. Objective The objective of this study was to evaluate aerobic exercise, without energy restriction, on weight loss in sedentary overweight and obese men and women. Design and Methods This investigation was a randomized, controlled, efficacy trial in 141 overweight and obese participants (body mass index, 31.0 ± 4.6 kg/m2; age 22.6 ± 3.9 years). Participants were randomized (2:2:1 ratio) to exercise at either 400 kcal/session or 600 kcal/session or to a non-exercise control. Exercise was supervised, 5 days/week, for 10 months. All participants were instructed to maintain usual ad libitum diets. Due to the efficacy design, completion of ≥ 90% of exercise sessions was an a priori definition of per protocol, and these participants were included in the analysis. Results Weight loss from baseline to 10 months for the 400 and 600 kcal/session groups was 3.9 ± 4.9kg (4.3%) and 5.2 ± 5.6kg (5.7%), respectively compared to weight gain for controls of 0.5 ± 3.5kg (0.5%) (p<0.05). Differences for weight loss from baseline to 10 months between the exercise groups and differences between men and women within groups were not statistically significant. Conclusions Supervised exercise, with equivalent energy expenditure, results in clinically significant weight loss with no significant difference between men and women.

Influence of menopause on body fat induced by aerobic training

“…With women in the ovulatory state (OS), understood as having a normal reproductive and menstrual cycle, KostrzewaNowak et al 6 verified a 3.0% body fat loss and Foster-Schubert et al 7 found a reduction of 1.6% of body fat in postmenopausal women (MN). In these same studies, individual analyses revealed that in the same training program, some participants gained body fat, thus indicating a variability in weight loss induced by training programs, which is confirmed in other studies 1,8 . As a result, recent research has investigated factors that explain greater weight loss in some and only modest results in others.…”

Nonexercise Energy Expenditure and Physical Activity in the Midwest Exercise Trial 2

“…RMR decreased in both the 400 and 600 kcal·session −1 groups, reflecting exercise induced weight loss (~5%) (8) and was essentially unchanged in controls reflecting minimal weight gain in the control group (8). …”

“…These compensatory changes could reduce the magnitude of exercise induced weight loss. Compensatory changes in energy intake and/or NEEx are also suggested by studies reporting no additional weight loss with increased exercise dose (3, 8, 29). …”

“…NEPA and NEEx were unpowered secondary outcomes. A detailed description of the design and methods for MET-2 (9), and the results for the primary aims (8) have been published previously. Data regarding changes in energy and macronutrient intake and the effect of changes in NEPA and NEEx on weight change will be reported separately.…”

The Utility of Exercise for Weight Control

“…As a health professional, I would never refute this or discourage anyone whose goal is to lose weight from engaging in exercise. After all, the American College of Sports Medicine has issued specific recommendations for exercise when weight loss is the primary goal [2] and some have shown that aerobic exercise by itself results in meaningful weight loss [3,4]. For weight loss to occur, energy expenditure must exceed energy intake, making it is easy to assume that increasing energy expenditure through exercise would favorably tip this balance towards weight loss.…”