New models predict skeletal muscle mass reduction with calorie restriction

A recent study has shown that healthy men and women with overweight or obesity who undergo voluntary calorie restriction (CR), without a structure exercise program, attain decreases in skeletal muscle (SM) mass of approximately 2 to 2.5 kg and 1 to 1.5 kg per 10-kg weight loss, respectively.

Study authors developed models to predict the relative reduction in SM mass during periods of voluntary CR and to validate model predictions in longitudinally monitored samples. A total of 897 healthy nonexercising adults who had whole-body SM mass measured with magnetic resonance imaging formed the model development group.

Notably, two longitudinal studies evaluated these model predictions of relative SM changes with CR. One was 12 to 14 weeks long and included 74 participants, while the other lasted for 12 months and involved 26 participants.

The authors created a series of SM prediction models in a sample of 415 men and 482 women. Mean SM mass changes predicted by such models, when compared with changes in body weight (ie, ΔSM/Δbody weight) with a representative model, were 0.26 in men and 0.14 in women (sex difference: p<0.001).

In the longitudinal studies, the actual mean proportions of weight loss as SM were 0.23 in men and 0.10 in women, which were comparable to values generated by the prediction models.

“These estimates are predicted to be influenced by interactions between age and body mass index in males, a hypothesis that needs future testing,” the authors said.