I recently had the privilege of attending Obesity Week 2025, the leading international conference dedicated to obesity science, healthcare, and policy. This gathering of over 4,400 obesity researchers, clinicians, and healthcare professionals met in Atlanta, GA to share the latest clinical research, evidence-based treatments, prevention strategies, and public policy efforts addressing obesity. This year’s theme, emphasizing “Obesity as a Chronic Disease,” covered multidisciplinary approaches including nutrition, physical activity, psychology, medical and surgical interventions, and public health advocacy, to improve outcomes for people living with obesity.
Muscle Loss From Ozempic and Mounjaro: What the Research Shows
I found one of the most common topics of discussion to be the growing concern over loss of muscle mass resulting from the use Ozempic (semaglutide) and Mounjaro (tirzepitide), which is a real concern when it comes to the rapid weight loss these medications can produce. In fact, GLP-1 agonists typically induce a loss of lean mass in the form of muscle and water that accounts for about 30% to 40% of the total weight loss. For example, if a patient loses 10 lbs of total body weight, approximately 3-4 lbs (30-40%) of that can be muscle and water. This can be particularly concerning in that significant loss of muscle generally leads to loss of strength and coordination increasing risk for low back strain injuries, falls, and fractures.
Natural Weight Loss and Lean Mass: How Diet and Exercise Affect Muscle
However, I was surprised to learn that even weight loss through more “natural” means, such as healthy plant-predominant diet and exercise, still typical results in at least 20-25% loss muscle mass and some water! Fortunately, this percentage can be reduced to 10-15% by increasing the amount of muscle building “resistance” exercising an individual performs as part of their weight-loss strategy. This means that with a loss of 10 lbs only 1 lb or so would be lost muscle mass.
How to Prevent Muscle Loss on Ozempic: Protein and Resistance Training
The take home message here is regardless of by what means you choose to restrict your calories, including through the use of popular and effective medications like Ozempic (semaglutide) or Mounjaro (tirzepatide), the addition of exercise and adequate protein intake (around 0.5 gram per pound of body weight) during weight loss is critical to minimize lean mass loss and preserve muscle strength and function. For example, if you weigh 200lbs and are attempting to lose weight by reducing how much you eat, you should be sure to consume at least 100g of protein daily. Understanding that most protein shakes contain only 20-30g per serving, while 6oz of salmon or chicken contains 35-40g, you will need 3-4 serving daily while dieting to maintain adequate muscle mass. You can pretty much search online for the protein content of any food as long as you know the portion size.
Best Practices to Maintain Muscle While Losing Weight
While weight loss by any means, typically results in 25-30% of the weight lost being muscle (and some water), this percentage can be reduced to 10-15% by eating at least ½ gram of protein for every pound you weigh PLUS doing various exercises at least 2-3 times per week that work all you muscle groups to near fatigue, ideally with 8 to 12 repetitions per set and 2 to 3 sets per exercise. This frequency helps stimulate muscle protein synthesis and maintain or even build muscle despite being in a calorie deficit.