Protecting Your Muscle on a GLP-1: Strength Training, Protein, and Exercise

Losing weight on a GLP-1 medication usually means losing some muscle too. The good news: strength training and enough protein protect most of it. This guide covers what the research shows and what to do about it.

Am I losing muscle while losing weight?

Yes, some. Here is what the research shows:

• About a quarter of the weight lost is lean tissue. A 2026 review of 35 randomized trials found that, on average, about 28% of the weight people lost on GLP-1-type medications was lean tissue. In most studies it fell between 16% and 40% (1).
• Lean tissue is not all muscle. In the STEP 1 trial of semaglutide, 38% of the roughly 30 lb (13.6 kg) lost was lean mass. Only about half of lean mass is muscle, so roughly 20% of the weight lost was actual muscle (2).
• "Lean mass" also includes water, organs and connective tissue. That means "lean mass loss" overstates true muscle loss (3).
• Your body composition usually still improves. You lose fat faster than lean tissue, so the share of your body that is lean actually goes up (4, 5).
• This is not unique to GLP-1s. Dieting, very-low-calorie diets and weight-loss surgery cause similar muscle loss for the same amount of weight lost (2, 6).
• Some people are at higher risk. These include older adults, women around and after menopause, people with low testosterone, people who are inactive or don't strength train, and people who eat little protein (2).
• There are still unknowns. No trial has yet measured whether this lean-tissue loss affects real-world strength or daily function. Its long-term health effects are also unknown (1, 7).

How can I prevent muscle loss on a GLP-1?

Four major nutrition and obesity organizations recommend the same core plan (2). The American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society issued it together.

1. Strength train. This is the foundation. Protein alone does not protect muscle if you aren't lifting. Extra protein your muscles can't use may be stored as fat (2).
2. Eat enough protein.
   • While actively losing weight: about 1.0 to 1.5 grams per kilogram of adjusted body weight per day, and at least 60 grams a day (8). Your clinician can calculate your adjusted body weight.
   • Once you reach maintenance: about 0.8 to 1.0 grams per kilogram per day (8).
   • Some reviews suggest 1.2 to 1.6 grams per kilogram per day. Going above 1.6 adds little (9, 10).
   • Spread it across the day, about 25 to 30 grams per meal (8, 10).
3. Make protein easy when your appetite is low. Eat the protein on your plate first. Choose compact protein foods such as fish, eggs, Greek yogurt, cottage cheese and beans or lentils. Protein shakes are fine when you need them (2).
4. Don't lose weight too fast. Fast weight loss increases muscle and bone loss. Losing 14% or more of your body weight in 3 to 4 months, or more than 5% in one month, is a reason to check on bone health. One review suggests aiming for about 1 to 2 lb (0.5 to 1.0 kg) per week (2, 9, 11).
5. Track your progress. A smart scale that estimates body composition is cheap and easy to repeat. A DXA scan is the most accurate option and can be done every 1 to 2 years. Grip strength or a 6-minute walk test can show whether your strength and fitness are holding up (2, 6).

Should I lift weights while taking a GLP-1?

Yes. This is the best-supported recommendation in this guide.

• It protects muscle. In diet-based weight-loss trials, strength training cut lean-mass loss by 50% to 95%. One analysis found it prevented 93% of lean-mass loss without slowing fat loss (6, 7).
• It protects bone. In one trial, a year of GLP-1 treatment plus exercise kept bone density steady. GLP-1 treatment alone lowered it (2).
• Start gently. Tiredness and nausea are common while your dose is being raised, so start with lighter sessions and build up over time (3, 6).

Knowledge is only half the battle

Knowing what to do is not the same as getting it done

The research says to lift weights and eat enough protein. It does not tell you which exercises fit your body, your joints, your schedule, and your experience, or how to progress them while you are eating much less.

This guide gives you the best evidence available, but research describes averages, and you are not an average. As a physician, I have worked with hundreds of people on GLP-1s. I combine the highest quality evidence with that experience and with your specific situation, preferences, and goals to build a plan that works for you, then adjust it as you go.

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What's the best workout program for GLP-1 users?

No program has been proven best specifically for people on GLP-1s. The American Heart Association says the right amount, intensity and type of exercise for GLP-1 users still needs study (7). Based on expert consensus, this is a sound starting template:

Part of the program	Target	References
Strength training	2 to 3 sessions a week (one advisory says 3 or more), working all major muscle groups and gradually increasing the weight; about 60 to 90 minutes a week total	2, 3, 6, 9
Cardio	Build up to at least 150 minutes a week of moderate activity, or 75 minutes of vigorous activity	2, 6, 7
Long-term maintenance	30 to 60 minutes of cardio a day, plus strength training 2 to 3 times a week	6
Balance and mobility	Add for older adults or anyone at risk of muscle loss	6, 8
Tracking	Grip strength, 6-minute walk test, and periodic body composition scans	2, 6

Combining cardio and strength training has the strongest support. A trial in the New England Journal of Medicine studied older adults with obesity who were dieting (12):

• The combined program improved physical function the most.
• Cardio alone lost the most lean mass and hip bone density.
• Strength training, alone or combined with cardio, protected both.

Is walking enough exercise while taking a GLP-1?

Walking is valuable, but on its own it is not enough to protect your muscle.

• Why it falls short: during fast weight loss, cardio alone protects lean mass less well than strength training (2, 12).
• What walking does well: it improves fitness, heart and metabolic health, and blood sugar control. It also helps keep weight off (7).
• How to use it: make walking your base for cardio and for moving more through the day. Pair it with 2 to 3 strength sessions a week. Wearing an activity tracker adds about 1,800 steps a day on average (13).

How can I build muscle while losing weight?

It is possible, but limited. It is most realistic for beginners, people returning to training after a break, and people with obesity.

• You need both strength training and protein. In a trial of older adults losing weight, only the group that did both actually gained lean mass, about 1.3 lb (0.6 kg). Protein alone or exercise alone did not (14).
• Coaching helps. A virtual GLP-1 program with structured activity coaching raised people's muscle percentage more than usual care over 12 weeks (15).
• The keys: gradually lift heavier over time, eat protein at the upper end of your target spread evenly across meals, and lose weight at a moderate pace.
• Set realistic goals. For most people, the realistic win is keeping the muscle you have and getting stronger, not adding a lot of new muscle.

This guide is for education only. Talk with your prescriber before changing your medication, diet or exercise plan.

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More in the GLP-1 guide series

• How to Eat on a GLP-1
• Managing GLP-1 Side Effects
• Is My GLP-1 Working?
• Why Isn't the Scale Moving?
• Keeping the Weight Off

References

1. Batsis JA, Gavras A, Gross DC, et al. Effect of incretin-based and nonpharmacologic weight loss on body composition: a systematic review. Annals of Internal Medicine. 2026.
2. Mozaffarian D, Agarwal M, Aggarwal M, et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and the Obesity Society. The American Journal of Clinical Nutrition. 2025.
3. Sukurica E, Sengul GF, Uysal Cinar F. Weight loss or muscle loss? Cellular mechanisms and clinical strategies for preserving lean mass during GLP-1-based therapy. Diabetes, Obesity & Metabolism. 2026.
4. Laverde LP, Muñoz-Velandia OM, Alfonso D, Gómez Medina AM. Effect of GLP-1 receptor agonists at doses for obesity management on muscle health: systematic review and meta-analysis of randomized controlled trials. International Journal of Obesity. 2026.
5. Bhandarkar A, Bhat S, Kapoor N. Effect of GLP-1 receptor agonists on body composition. Current Opinion in Endocrinology, Diabetes, and Obesity. 2025.
6. Mehrtash F, Dushay J, Manson JE. Integrating diet and physical activity when prescribing GLP-1s—lifestyle factors remain crucial. JAMA Internal Medicine. 2025.
7. Swift DL, Ross LM, Laddu DR, et al. Role of physical activity in obesity treatment and cardiometabolic health: a scientific statement from the American Heart Association. Circulation. 2026.
8. Koufakis T, Tentolouris A, Manthou E, et al. Skeletal muscle in vulnerable populations receiving cardiorenal-metabolic therapies: SGLT2 inhibitors, incretin-based therapies, and the challenge of precision medicine. Advances in Therapy. 2026.
9. Eisa N, Barood O. Lean mass changes with incretin therapy versus lifestyle intervention: a systematic review and meta-analysis of randomised controlled trials. Diabetes, Obesity & Metabolism. 2026.
10. Mesinovic J, Hurst C, Leung GKW, et al. Exercise and dietary recommendations to preserve musculoskeletal health during weight loss in adults with obesity: a practical guide. Reviews in Endocrine & Metabolic Disorders. 2025.
11. Moiz A, Peters TM, Tsoukas MA, et al. Balancing the benefits and risks of GLP-1 receptor agonists: a clinical guide for shared decision-making. EClinicalMedicine. 2026.
12. Villareal DT, Aguirre L, Gurney AB, et al. Aerobic or resistance exercise, or both, in dieting obese older adults. The New England Journal of Medicine. 2017.
13. Elmaleh-Sachs A, Schwartz JL, Bramante CT, et al. Obesity management in adults: a review. JAMA. 2023.
14. Verreijen AM, Engberink MF, Memelink RG, et al. Effect of a high protein diet and/or resistance exercise on the preservation of fat free mass during weight loss in overweight and obese older adults: a randomized controlled trial. Nutrition Journal. 2017.
15. Stanton LA, Naqvi JB, Devaraj SM, et al. Quality plus quantity: evaluation of a virtual GLP-1 programme with physical activity support to promote healthy body composition change during GLP-1 weight loss. Diabetes, Obesity & Metabolism. 2026.