Objective:

To analyze muscle-related losses in incretin-based weight-loss interventions compared to nonpharmacologic interventions, emphasizing the significance of these losses.

Key Findings:

• Muscle-related losses exceeded benchmarks in about two-thirds of incretin interventions and half of comparator interventions, indicating a significant concern for muscle preservation.
• Median proportion of total weight loss from muscle-related tissue in incretin groups was about 35%, raising questions about treatment strategies.
• 83% of higher-efficacy studies exceeded muscle-loss benchmarks compared to 62% for lower-efficacy therapies, highlighting the need for careful monitoring.

Interpretation:

Muscle loss exceeding expected proportions is not unique to incretin therapies and may reflect broader physiological responses to weight loss, necessitating a reevaluation of treatment success metrics.

Limitations:

• Seventeen of 36 studies did not report muscle-related outcomes, which may skew results.
• Measurement methods varied widely, limiting comparability and potentially affecting the reliability of findings.
• Most participants were younger or middle-aged, limiting generalizability to older populations and raising concerns about the applicability of results.

Conclusion:

The findings highlight the need for refined definitions of treatment success, emphasizing the importance of preserving muscle mass during weight loss to ensure overall health.