Nutrition support whilst on glucagon-like peptide-1 based therapy. Is it necessary?

Weight loss is a primary goal in the treatment of obesity, but its effect on body composition - particularly fat-free mass (FFM) and skeletal muscle mass (SM) - is of increasing concern. This review examines the effects of antiobesity medications, particularly glucagon-like peptide-1 receptor analogs (GLP-1 RA), on body composition, the risk of sarcopenia, and strategies to preserve muscle mass during pharmacological weight loss.

Studies have shown that while GLP-1 RA are effective in reducing fat mass, up to 40% of the total weight loss can come from FFM. However, it is important to distinguish between FFM and SM, as FFM includes nonmuscle components. Resistance training and adequate protein intake can mitigate muscle loss, but the evidence for their efficacy in the context of GLP-1 RA therapy is mixed. If these measures are insufficient to prevent and maintain muscle mass, the use of some nutrients, such as branched chain amino acids, creatine, leucine, omega-3 fatty acids and vitamin D, may be beneficial. Newer pharmacological approaches, such as bimagrumab, a human monoclonal antibody that acts by binding to the activin type II receptor II (ActRII), and other activin or myostatin inhibitors, show promise in preserving muscle mass while promoting fat loss.

GLP-1 RA therapy for obesity should include resistance training, optimal protein intake and, if needed, specific nutrients and possibly pharmacological interventions to preserve muscle mass. Further research is needed to assess the long-term effects of GLP-1 RA on muscle health and to refine strategies to prevent sarcopenia in patients undergoing pharmacological weight loss.