Nutrition, Health Behavior and Obesity Research Lab

The rapid emergence of incretin-based obesity management medications (OMMs) has transformed the therapeutic landscape of weight management. Treatments such as Wegovy (semaglutide) and Mounjaro (tirzepatide) have demonstrated unprecedented weight reduction in adults with overweight and obesity. However, alongside meaningful fat loss, a substantial proportion of total weight reduction may derive from lean body mass (LBM), raising concerns regarding muscle preservation, functional capacity, metabolic adaptation, and long-term weight maintenance, particularly among older adults.

This multi-center randomized controlled trial aims to evaluate whether a structured adjunct intervention, a daily protein supplementation combined with resistance training, can mitigate lean mass loss and optimize body composition during six months of incretin-based pharmacotherapy. A total of 240 adults (≥45 years) initiating treatment with semaglutide or tirzepatide will be randomized to receive either protein supplementation (25 g/day) plus a supervised and home-based resistance training program, or standard lifestyle recommendations alone.

Participants undergo comprehensive assessments at baseline, 3 months, and 6 months. Measurements include body composition (via bioelectrical impedance analysis and DXA), resting metabolic rate, nitrogen balance, skeletal muscle strength and performance tests, physical activity, dietary intake, biochemical markers, and a battery of validated behavioral questionnaires. Nitrogen balance analysis will further enable estimation of individualized protein requirements during pharmacologically induced weight loss.

Setting
The Ichilov and Assuta Medical Centers in Tel Aviv

Primary supervision
Dr. Shiri Sherf-Dagan
Dr. Asaf Buch
Dr. Tair Ben-Porat.

Project status                                                                                                                                                 

Currently recruiting, data collection is ongoing                                      

Useful links                                                                                                             

https://osf.io/nytk9/overview