Older adults over 65 years of age with obesity are physically not all the same, exhibiting distinct trajectories and responses to weight-loss interventions. Incretin mimetic drugs (IMDs) such as semaglutide and tirzepatide are increasingly prescribed and can induce substantial weight loss1often accompanied by reductions in fat and muscle. Given the central role of muscle in strength, mobility and independence, its preservation has clinical relevance in older adults. These shifts in body composition have renewed interest in muscle─fat dynamics, particularly sarcopenic obesity, defined by increased fat mass and reduced muscle health2. Regardless of its definition, sarcopenic obesity is consistently associated with worse physical function, lower quality of life and higher mortality than either sarcopenia or obesity alone3.
Data have shown that lifestyle-based, structured diet and exercise programs supported by behavioral counseling reduce obesity-related complications but may cause unintended losses in lean mass, which includes muscle mass, connective tissue, viscera, and bone density and content; this necessitates a careful balance of benefits and harms4. In older adults, these losses are clinically meaningful, translating to declines in strength, balance and resilience. Most trials report body composition changes over 6–12 months, with limited long-term data.
