Macro partitioning
Incretin-mimetic drugs (IMDs) such as semaglutide and tirzepatide cause significant skeletal muscle mass loss (≥10%) during rapid weight reduction, a loss comparable to 20 years of age-related decline.
If you are taking GLP-1 or GIP/GLP-1 drugs, expect to lose muscle along with fat. This is not just 'water weight'; it is functional tissue. To mitigate this, you must prioritize protein intake and engage in resistance training, as these are the only proven strategies to preserve muscle during rapid weight loss.
Available evidence suggests that clinical trial participants receiving IMDs for the treatment of obesity lost 10% or more of their muscle mass during the 68- to 72-week interventions, approximately equivalent to 20 years of age-related muscle loss.
Why this rating
Based on pivotal phase 3 trials (STEP-1, SURMOUNT-1) with DXA analysis, though exact muscle vs. lean mass distinction is noted as imperfect.
Source
Strategies for minimizing muscle loss during use of incretin‐mimetic drugs for treatment of obesity
Jeffrey I. Mechanick et al. · Obesity Reviews · 2024
DOI 10.1111/obr.13841
More from this paper
- Combining incretin-mimetic drug therapy with resistance training and adequate protein intake minimizes skeletal muscle loss and preserves metabolic health.Good
- Oral nutritional supplements (ONS) containing high-quality protein and micronutrients are an effective strategy to prevent nutrient deficiencies and support muscle health in patients with reduced appetite from IMDs.Moderate
Related findings · Macro partitioning
- Total daily protein intake of 1.6 g/kg/day is sufficient for maximizing resistance training-induced muscle gains, with an upper confidence interval of 2.2 g/kg/day.Strong
- Resistance exercise training combined with sufficient dietary protein intake acts synergistically to maximize skeletal muscle hypertrophy, with protein intake saturating around 1.6 g/kg/day for general populations and potentially requiring 2.0-2.2 g/kg/day for resistance-trained individuals.Strong
- Trans fats should be completely eliminated from the diet, as they increase LDL cholesterol, decrease HDL cholesterol, and are directly associated with increased coronary risk.Strong
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