GLP-1 Protein Calculator: Protein Targets During Weight-Loss Therapy
A GLP-1 protein calculator estimates daily protein during weight loss on a GLP-1 medication such as semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound). A 2025 joint advisory from four nutrition and obesity societies notes that 1.2 to 1.6 g/kg per day has been proposed during active weight reduction, above the 0.8 g/kg RDA.[1] For a 100 kg person that is 120 to 160 g, or 96 to 128 g on an 80 kg reference weight.
GLP-1 protein calculator
Estimate from published ranges, not a prescription. The RDA is a minimum; ask your clinician or a registered dietitian what fits you.
How much protein should you eat on a GLP-1 medication?
A range of 1.2 to 1.6 g/kg per day has been proposed during active weight reduction, but no single number is set for everyone. A 2025 joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society states that the protein RDA is 0.8 g/kg per day, a figure that comes from the National Academies 2005 dietary reference intakes.[1][3] For a 100 kg person, 1.2 to 1.6 g/kg is 120 to 160 g a day, against 80 g at the RDA. Semaglutide is the active ingredient in Ozempic and Wegovy, and tirzepatide is the active ingredient in Mounjaro and Zepbound.[4][5][6][7] The advisory names semaglutide and tirzepatide among GLP-1 medicines but gives no separate protein figure for either.[1] The calculator prints the range for the weight you enter, shows the RDA line beside it, and leaves the choice of target to you and your care team.
Why does protein matter more during GLP-1 weight loss?
Protein matters more because eating less leaves less room for it at each meal, and not all lost weight is fat. The 2025 joint advisory reports energy intake reductions of 16% to 39% with GLP-1 medications.[1] For someone who usually eats 2,000 kcal a day, simple arithmetic gives 320 to 780 kcal less food, or about 1,220 to 1,680 kcal. The advisory cites data in which an average 13.6 kg weight reduction was 8.3 kg of fat mass and 5.3 kg of lean body mass, which is 38%.[1] Its stated response is to prescribe the medication together with a structured exercise program, aiming for regular strength training at least three times a week, and to involve registered dietitians in care.[1] Protein intake sits beside that plan, not in place of it. The advisory discusses GLP-1 medicines as a group, so the same reasoning covers Ozempic, Wegovy, Mounjaro and Zepbound.
Should you use current weight or goal weight for protein on a GLP-1?
There is no agreed answer, because experts have not settled which weight to use. The 2025 joint advisory says it is unclear whether protein targets should be based on actual weight, adjusted or ideal weight, or fat-free mass, and that actual weight can significantly overestimate needs in people with obesity.[1] The gap can be big. At 1.2 to 1.6 g/kg, a 100 kg current weight gives 120 to 160 g, while an 80 kg reference weight gives 96 to 128 g. In pounds, 198 lb is 89.8 kg and gives 108 to 144 g, while a 165 lb reference weight is 74.8 kg and gives 90 to 120 g. The calculator shows both ranges together and does not pick a winner. If your clinician or dietitian gives you a reference weight, enter that number in the second box and talk with them about which range fits you.
| Weight | RDA at 0.8 g/kg | 1.2 g/kg | 1.6 g/kg | Avoid prolonged, 2.0 g/kg |
|---|---|---|---|---|
| 70 kg | 56 g | 84 g | 112 g | 140 g |
| 80 kg | 64 g | 96 g | 128 g | 160 g |
| 90 kg | 72 g | 108 g | 144 g | 180 g |
| 100 kg | 80 g | 120 g | 160 g | 200 g |
| 110 kg | 88 g | 132 g | 176 g | 220 g |
| 120 kg | 96 g | 144 g | 192 g | 240 g |
| 130 kg | 104 g | 156 g | 208 g | 260 g |
Is there an upper or lower limit for protein on a GLP-1?
Yes, the 2025 joint advisory names both ends. At the low end, protein intake in adults should not fall below 0.4 to 0.5 g/kg per day, because that can lead to muscle atrophy.[1] For a 100 kg person that floor is 40 to 50 g a day. At the high end, it says prolonged intake at or above 2 g/kg per day should be avoided because of potential adverse health effects.[1] That is 200 g or more at 100 kg, and the last column of the table above shows it at other weights. Between those limits sit the RDA of 0.8 g/kg and the proposed 1.2 to 1.6 g/kg range. These lines apply to adults without special conditions. People with kidney disease, or anyone given a protein limit by a clinician, should follow that advice instead.
Do adults over 65 on a GLP-1 need more protein?
Adults over 65 are advised at least 1.0 to 1.2 g/kg per day, which is already above the 0.8 g/kg RDA. The PROT-AGE Study Group recommends that adults over 65 average at least 1.0 to 1.2 g/kg per day, with 1.2 g/kg or more for those who exercise and are otherwise active, and 1.2 to 1.5 g/kg for most older adults with acute or chronic disease.[2] For an 85 kg person that is 85 to 102 g at the base range and 102 to 128 g with illness. The same paper says older people with severe kidney disease who are not on dialysis may need to limit protein.[2] The 1.2 to 1.6 g/kg GLP-1 range from the joint advisory overlaps these figures.[1] The general protein calculator on this site has over 65 profiles, and a clinician can tell you which range applies to you.
What else does the advisory say about nutrition on a GLP-1?
Beyond protein, the 2025 joint advisory warns about nutrient shortfalls and fluid loss. It says deficiency risk rises especially at energy intakes below 1,200 kcal a day for females and below 1,800 kcal a day for males.[1] On fluids, it states that dehydration from severe nausea, vomiting or diarrhea can cause acute kidney injury, and it lists ensuring adequate fluids among the habits to encourage.[1] The Ozempic label reports the same pattern: the majority of acute kidney injury events occurred in patients who had gastrointestinal reactions leading to dehydration such as nausea, vomiting, or diarrhea.[4] The Wegovy, Mounjaro and Zepbound labels carry matching warnings and tell prescribers to monitor kidney function in patients who report reactions that could cause volume loss.[5][6][7] This page does not suggest a calorie target or a dose. Persistent vomiting or diarrhea, or being unable to keep fluids down, is a reason to contact your prescriber.
Frequently asked questions
How much protein should I eat on Ozempic?
There is no Ozempic-specific protein figure. The 2025 joint advisory gives the RDA of 0.8 g/kg per day and says 1.2 to 1.6 g/kg per day has been proposed during active weight reduction. Ozempic contains semaglutide. Your prescriber or a registered dietitian can set a target for you.
Is 100 grams of protein enough on Ozempic or Wegovy?
It depends on your weight and the range you follow. 100 g is 1.25 g/kg at 80 kg, inside the proposed 1.2 to 1.6 g/kg range. At 100 kg it is 1.0 g/kg, below that range and above the RDA. Ask your care team.
Does Mounjaro or Zepbound need more protein than Ozempic or Wegovy?
The 2025 joint advisory does not give separate protein recommendations for semaglutide and tirzepatide. The proposed 1.2 to 1.6 g/kg range is described for active weight reduction in general. Your clinician can say whether anything changes for you.
Will protein alone prevent muscle loss?
The advisory does not present protein as a stand-alone fix. It advises prescribing GLP-1 medication with a structured exercise program, aiming for strength training at least three times a week, and it gives a role to registered dietitians.
Should I use protein shakes?
The advisory ranges are about total daily protein, and this page does not recommend products. If you are struggling to reach your range with food, a registered dietitian can say what fits your health and your medication.
Does PepTrac set my protein goal?
No. You choose the goal, and PepTrac tracks your progress next to calories and water. It also logs meals, including an AI meal scan from a photo. PepTrac is free to download on iPhone, with an optional PepTrac Pro.
Is this GLP-1 protein calculator medical advice?
No. It does arithmetic on a proposed range from a published advisory. Kidney disease, pregnancy, and other conditions change protein and fluid needs, so follow the plan from your prescriber and dietitian over any calculator.
Sources
- American College of Lifestyle Medicine, American Society for Nutrition, Obesity Medicine Association, The Obesity Society (Obesity, 2025). Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory. Accessed October 3, 2026.
- Journal of the American Medical Directors Association. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. Accessed October 3, 2026.
- Frontiers in Nutrition. Current Concepts and Unresolved Questions in Dietary Protein Requirements and Supplements in Adults (Phillips, 2017). Accessed October 3, 2026.
- DailyMed, National Library of Medicine (Novo Nordisk). Ozempic (semaglutide) injection prescribing information. Accessed October 3, 2026.
- DailyMed, National Library of Medicine (Novo Nordisk). Wegovy (semaglutide) prescribing information. Accessed October 3, 2026.
- DailyMed, National Library of Medicine (Eli Lilly). Mounjaro (tirzepatide) injection prescribing information. Accessed October 3, 2026.
- DailyMed, National Library of Medicine (Eli Lilly). Zepbound (tirzepatide) prescribing information. Accessed October 3, 2026.
Written and maintained by the team that builds PepTrac. Every calculator on this site runs the same tested math as the app. Read how we research, cite, and update pages in our editorial policy.
