Muscle matters: the effects of medically induced weight loss on skeletal muscle
Volume 12, Issue 11p785-787November 2024Download Full Issue
Carla M Pradoa ∙ Stuart M Phillipsb ∙ M Cristina Gonzalezc,d ∙ Steven B Heymsfieldd steven.heymsfield@pbrc.edu
The importance of skeletal muscle mass is increasingly being recognised in the medical field.1 The crucial roles of skeletal muscle have come to the forefront of public attention due to data on the use of GLP-1 receptor agonists, which are effective for weight loss, but can cause substantial muscle loss. Studies suggest muscle loss with these medications (as indicated by decreases in fat-free mass [FFM]) ranges from 25% to 39% of the total weight lost over 36–72 weeks.2 This substantial muscle loss can be largely attributed to the magnitude of weight loss, rather than by an independent effect of GLP-1 receptor agonists, although this hypothesis must be tested. By comparison, non-pharmacological caloric restriction studies with smaller magnitudes of weight loss result in 10–30% FFM losses.3 In context, on an annual basis, the decline in muscle mass with GLP-1 receptor agonists is several times greater than what would be expected from age-related muscle loss (0·8% per year based on 8% muscle loss per decade from ages 40–70 years). Dismissing the importance of muscle loss can create a disconnect between patients' increased awareness of muscle and the role it plays in health, and clinicians who downplay these concerns, affecting adherence to and the development of optimised treatment plans.