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

Med Sci Sports Exerc. 2017 Jan;49(1):206-217. doi: 10.1249/MSS.0000000000001074.


Purpose: This study aimed to evaluate the hypothesis that exercise attenuates the reductions in lean mass, muscle strength, bone mineral density, and V˙O2max that accompany modest weight loss induced by calorie restriction (CR).

Methods: Overweight, sedentary women and men (n = 52, 45-65 yr) were randomized to 6%-8% weight loss by using CR, endurance exercise training (EX), or both (CREX). The CR and the CREX groups underwent counseling to reduce energy intake by 20% and 10%, respectively. The EX and the CREX groups exercised 7.4 ± 0.5 and 4.4 ± 0.5 h·wk, respectively. Before and after 16.8 ± 1.1 wk of weight loss, lean mass and bone mineral density were measured with dual-energy x-ray absorptiometry, strength was measured with dynamometry, and aerobic capacity (V˙O2max) 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% CR in overweight women and men decreases lean mass and reduces absolute V˙O2max. Exercise protects against these effects. Although 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.

Trial registration: ClinicalTrials.gov NCT00777621.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Body Mass Index*
  • Bone Density*
  • Caloric Restriction
  • Energy Metabolism / physiology
  • Exercise Therapy*
  • Humans
  • Middle Aged
  • Muscle Strength / physiology*
  • Overweight / therapy*
  • Oxygen Consumption / physiology*
  • Physical Conditioning, Human
  • Weight Loss / physiology*

Associated data

  • ClinicalTrials.gov/NCT00777621