GLP-1 Collective

GLP-1 Collective · Free tool · GLP-1 nutrition

How much protein do you need on a GLP-1?

Put your numbers in and you get two answers: how much protein the average adult needs, and how much you need on a GLP-1.

You can also find this tool and the rest of the set in the Toolbox inside GLP-1 Community Cozy Butter, a free online space for people taking GLP-1 medications. Cozy Butter shares a founder with the Collective. How this works.

Your numbers

What that looks like on a plate

4 oz chicken breast · 31 g 6 oz Greek yogurt · 17 g 1 scoop whey · 24 g 2 large eggs · 12 g 4 oz firm tofu · 10 g 1 cup cottage cheese · 25 g

For the average adult

–g a day

The standard recommendation of 0.8 g per kg, for an adult who is not losing weight. It is the minimum to avoid running short, figured on the same weight as the GLP-1 number so the two compare fairly.

If you are on a GLP-1

–g a day

Why the GLP-1 number is higher

Losing weight quickly while eating less puts muscle at risk, and in the semaglutide and tirzepatide trials a quarter or more of the weight lost was fat-free mass. Eating more protein, with strength work, helps you keep it. The general number was set for adults who are not losing weight, so it was never meant as a target here.

How your number is built

This is education, not medical advice

Protein targets have to be individualized. Higher protein intake may be inappropriate if you have chronic kidney disease, liver disease, or are pregnant or breastfeeding. Talk to your prescriber or a registered dietitian before changing your intake, and ask for a body-composition measurement if one is available to you.

Why protein matters more on a GLP-1

You eat less, so protein slips first

These medications reduce appetite and slow digestion, so your total intake falls. Food aversion and changes in taste are common in the early weeks, and protein-dense food is often the first thing that stops appealing.

Some of the weight you lose is muscle

In the semaglutide and tirzepatide trials, fat-free mass accounted for about 25% to 40% of the weight participants lost. Reviewing those trials, Mechanick and colleagues estimate at least 10% of muscle mass lost over 68 to 72 weeks.

The more you have to lose, the more is at stake

A systematic review of significant weight loss found that the share coming from fat-free mass rises as the total loss gets larger. Researchers attribute the muscle loss seen on these medications to the amount of weight lost rather than to the drug itself.

Protein is only half of it

Strength work is what tells your body to keep the muscle. The Physical Activity Guidelines for Americans ask for muscle-strengthening activity on two or more days a week, alongside 150 to 300 minutes of moderate activity.

Sources

10 references
  1. Mechanick JI, Butsch WS, Christensen SM, Hamdy O, Li Z, Prado CM, Heymsfield SB. Strategies for minimizing muscle loss during use of incretin-mimetic drugs for treatment of obesity. Obesity Reviews. 2025;26(1):e13841. doi:10.1111/obr.13841. Open access. Source of the STEP 1 and SURMOUNT-1 body-composition figures, the ideal- and adjusted-body-weight conventions, and the 60 g/day floor.
  2. Prado CM, Phillips SM, Gonzalez MC, Heymsfield SB. Muscle matters: the effects of medically induced weight loss on skeletal muscle. The Lancet Diabetes & Endocrinology. 2024;12(11):785–787. doi:10.1016/S2213-8587(24)00272-9.
  3. Mozaffarian D, 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;122:344–367. Full text.
  4. Cava E, Yeat NC, Mittendorfer B. Preserving healthy muscle during weight loss. Advances in Nutrition. 2017;8(3):511–519. doi:10.3945/an.116.014506.
  5. Dekker IM, van Rijssen NM, Verreijen A, et al. Calculation of protein requirements: a comparison of calculations based on bodyweight and fat free mass. Clinical Nutrition ESPEN. 2022. PMID 35331517.
  6. Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). New England Journal of Medicine. 2021;384(11):989–1002. doi:10.1056/NEJMoa2032183.
  7. Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). New England Journal of Medicine. 2022;387(3):205–216. doi:10.1056/NEJMoa2206038.
  8. Chaston TB, Dixon JB, O'Brien PE. Changes in fat-free mass during significant weight loss: a systematic review. International Journal of Obesity. 2007;31(5):743–750. doi:10.1038/sj.ijo.0803483. The source for the share of weight loss coming from fat-free mass rising with the size of the loss.
  9. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press, 2005. doi:10.17226/10490. Source of the 0.8 g/kg RDA.
  10. US Department of Health and Human Services. Physical Activity Guidelines for Americans, 2nd edition, 2018. health.gov.