Effects of Weight Loss on Lean Mass, Strength, Bone, and Aerobic Capacity

Abstract

Purpose To evaluate the hypothesis that exercise attenuates the reductions in lean mass, muscle strength, BMD, and VO2max that accompany modest weight loss induced by calorie restriction. Methods Overweight, sedentary women and men (n=52, 45–65y) were randomized to 6–8% weight loss by using calorie restriction (CR), endurance exercise (EX), or both (CREX). The CR and CREX groups underwent counseling to reduce energy intake by 20% and 10%, respectively. The EX and CREX groups exercised 7.4±0.5 and 4.4±0.5 hr/wk, respectively. Before and after 16.8±1.1 weeks of weight loss, lean mass and BMD were measured with dual-energy X-ray absorptiometry, strength was measured with dynamometry, and aerobic capacity (VO2max) was measured with indirect calorimetry during maximal-intensity treadmill exercise. Results Weight loss was ~7% in all groups. Decreases in whole body (~2%, p=0.003) and lower extremity (~4%, p<0.0001) lean mass occurred in the CR group (both p<0.05). Despite similar weight loss, these reductions were attenuated in the CREX group (~1%, p=0.44 and ~2%, p=0.05, respectively) and absent in the EX group. Absolute aerobic capacity decreased ~6% in the CR group (p=0.04), was unchanged in the CREX group (p=0.28) and increased ~15% in the EX group (p<0.0001). No changes in muscle strength or bone were observed. Conclusions Modest weight loss (~7%) induced by 20% calorie restriction in overweight women and men decreases lean mass and reduces absolute VO2max. Exercise protects against these effects. While the CR-induced changes might be considered physiologically appropriate for a reduced body weight, exercise preserves and/or improves these parameters during weight loss, which likely improves physical function. These findings support the notion of using exercise as an important component of weight loss programs.

A novel dual amylin and calcitonin receptor agonist, KBP‐089, induces weight loss through a reduction in fat, but not lean mass, while improving food preference

“…There was no difference in whole body fat mass between the KBP‐089‐treated and pair‐weighed rats; however, in support of the limited loss of lean mass, we found a slight – albeit significant – increase in lean mass in KBP‐089‐treated rats compared with vehicle rats, underscoring that the weight loss is primarily mediated through a reduction in adipose tissue weight. Furthermore, the slight increase in lean mass is a positive effect, as heavy weight loss in many cases is associated with loss in lean body mass in humans (Garthe et al ., ; Weiss et al ., ).…”

Effect of Exercise Modality During Weight Loss on Bone Health in Older Adults With Obesity and Cardiovascular Disease or Metabolic Syndrome: A Randomized Controlled Trial

“…Some, (21–25) but not all, (26–30) studies support this hypothesis. Differing results may be due to varying exercise prescriptions, with recent clinical trial data suggestive of a superior ability of supervised resistance training to preserve bone mass with weight loss compared to aerobic training, at least in the short-term.…”

“…Several studies show a positive effect of exercise on BMD in weight-stable, older adults, (18)(19)(20) and exercise may be an effective means to prevent bone loss during dietary WL. Some, (21)(22)(23)(24)(25) but not all, (26)(27)(28)(29)(30) studies support this hypothesis. Differing results may be based on varying exercise prescriptions, with recent clinical trial data suggestive of a superior ability of supervised resistance training to preserve bone mass with WL compared with aerobic training, at least in the short-term.…”

Exercise has the guts: How physical activity may positively modulate gut microbiota in chronic and immune-based diseases

“…In fact, exercise covers a broad spectrum of health benefits, from boosting mental wellness by enhancing mood states and neuroplasticity via augmented brain-derived neurotrophic factors (BDNF) levels [3], to help preventing excess weight gain or maintaining weight loss [1,[4][5][6], mastering a cascade of favorable events in the metabolic equilibrium of the human body. A substantial number of both crosssectional and longitudinal studies have indicated that regular physical exercise exerts diversified anti-inflammatory actions [7,8].…”