New data from a Vienna-based retrospective cohort of 486 patients (mean age 49.9, 82% female) presented at ECO2026 shows that GLP-1 and dual GIP/GLP-1 agonists drive 80-85% of weight loss from fat while holding relative skeletal muscle mass steady in over 70% of cases. After roughly 14 months, absolute muscle dropped only 1.2 kg versus 9 kg fat loss, and adjusted models found time on therapy unrelated to muscle once fat mass was accounted for. This observational design, lacking randomization and relying on bioelectrical impedance rather than gold-standard DEXA, still counters widespread fears of sarcopenic obesity that emerged from smaller trials and social-media anecdotes. Cross-referencing with the STEP 1 RCT (n=1961, NEJM 2021) reveals similar proportional fat-dominant loss when exercise counseling is provided, while a 2024 meta-analysis in The Lancet Diabetes & Endocrinology (18 trials, 12,000 participants) flags greater lean-mass loss only in subgroups without activity guidance. The Vienna clinic's universal exercise recommendations likely explain the favorable signal, an element many early reports overlooked. These findings reduce one key regulatory and payer concern, supporting broader insurance coverage and longer-duration use of semaglutide and tirzepatide. Remaining gaps include sparse male representation and follow-up beyond two years; future RCTs pairing GLP-1s with resistance training protocols will be decisive for confirming functional outcomes.