Understanding Impact of Anti‐Obesity Medications on Skeletal Muscle Mass Change Is Confounded by Measurement Methods

Anti-obesity medications promote greater degrees of weight loss than lifestyle interventions alone. There is an important need to understand whether loss of skeletal muscle during pharmacologically induced weight loss is clinically significant due to its essential role in health and disease. Most randomized, placebo-controlled studies addressing this question report on fat-free or lean mass estimated from dual-energy x-ray absorptiometry or bioelectrical impedance without defining the composition of these components. Fat-free, lean, and skeletal muscle mass are not synonymous terms, and studies frequently fail to define lean mass, which may or may not include bone. Lack of standard preparatory procedures prior to measurement, differences in medications, doses, or intervention lengths, and inclusion of varied lifestyle modifications prevent reaching a consensus regarding the impact on skeletal muscle of pharmacologically induced weight loss. There is a critical need for greater precision and depth of understanding when selecting a measurement method and describing body compartments.