A wave of recent articles and sponsored content has been focused on GLP-1s and lean muscle mass. While studies have shed some initial light on the effects of these medications on muscle loss, results are mixed. Hype aside, what should payers and employers consider when determining the right comprehensive weight management solution for their members? 

Navigating Lean Muscle Loss During Weight Loss 

Any weight loss effort, including those involving GLP-1 medications, will lead to reduction in lean body mass, including muscle, bones, organs, and water (basically anything that’s not body fat). Lean mass is associated with better metabolism—an individual’s resting metabolic rate improves as muscle mass increases—and loss of lean mass due to rapid weight loss in a short period can have complex effects.  

  • Muscle loss vs muscle quality: With the focus on GLP-1s and lean muscle mass, current discourse is not appropriately addressing the importance of muscle quality. Rather than just muscle mass, poor muscle quality is associated with adverse outcomes such as loss of mobility, disability, falls, fractures, and mortality. As muscle quality decreases, the ability to carry out basic physical activities (e.g., lifting objects, getting up from a chair, climbing stairs, walking) becomes increasingly difficult. 
  • Differences among populations: Older adults, who already experience declining muscle mass and strength with age, are at greater risk if obese or overweight. Studies have shown that genetics and ethnicity should be considered when recommending certain nutrition patterns that may impact weight loss, with or without the use of GLP1-s, and lean muscle mass. For example, Black individuals may lose more muscle mass when restricting calories compared to White individuals.  

Research indicates that approximately one-quarter to one-third of weight lost on GLP-1 drugs can be lean mass, not significantly different from weight loss achieved through calorie reduction (~20-30% of total weight loss in people who are overweight or obese). In fact, GLP-1 medications may reduce lean mass, including muscle, but the proportion of lean mass to total body mass can still improve overall. However, these complexities underscore the need for a comprehensive approach to improve body composition, not just preserving muscle, while achieving weight loss goals. 

Guidelines to Successfully Change Body Composition 

Evidence-based guidelines are emerging for counseling patients taking GLP-1s. For now, recommendations include standard nutrition and lifestyle changes to adjust body composition: 

  • Regular physical activity including cardio for fat loss and resistance training to improve muscle quality. 
  • Increase in protein intake to help with building muscle and preserving lean mass. 
  • Decrease in overall calories for fat loss. 

The Pivotal Role of Expert Support for Chronic Weight Management 

Not only is it challenging to track whether weight loss is from fat or muscle, but the variability of body weight changes is evident across populations. So, how can payers and employers deliver solutions that shepherd their populations through GLP-1 medication initiation, weight loss, and sustainable maintenance without the use of medication?  

To appropriately support individuals through weight loss and successful maintenance, especially for those on GLP-1s, solutions should include ongoing, personalized care from a registered dietitian.   

  • Physical activity recommendations: Telling an individual to increase their physical activity without understanding their limitations could lead to a decrease in motivation or, at worse, injury. Personalized guidance from an expert on appropriate exercises for cardio and resistance-based training is crucial for developing life-long lifestyle changes related to physical activity.  
  • Medical nutrition therapy: Individuals undergoing weight loss therapy, particularly GLP-1s, need personalized guidance from registered dietitians to ensure they are making appropriate nutrition decisions. This could mean protein needs (to mitigate muscle loss) but also sodium intake, carb counting, and other changes that may impact existing comorbidities. 

Everybody reacts to weight loss differently and chronic condition comorbidities can compound complications. For example, individuals with chronic kidney disease who experience rapid weight loss may lose a higher percentage of lean body mass. In addition to expert guidance, an integrated care solution may offer more comprehensive population-based care. 

While weight loss offers numerous health benefits, including improvements in metabolic risk factors, preserving lean muscle mass is essential for overall physical function and quality of life. By understanding the impact of rapid weight loss and GLP-1s on muscle composition, payers and employers can better support patients in achieving sustainable and healthy weight loss goals.