Free tool
GLP-1 protein calculator
Most adults losing weight do best with about 1.2 to 1.6 g of protein per kg of body weight a day, more if they strength train. Enter your details for a range sized to you, split into meals. Nothing you enter leaves your browser.
Example: change the numbers
115–150g a day
1.4–1.8 g per kg of body weight (82 kg), for losing weight, with strength training.
Split across
- 29–38g · meal 1
- 29–38g · meal 2
- 29–38g · meal 3
- 29–38g · meal 4
A simpler rule some clinicians use: about 80–120 g a day. General education for healthy adults, not medical advice.
The method
How the calculator works
- 1
Pick the right weight
Below a BMI of 30 we use your actual weight. At 30 or above we use an adjusted body weight: your ideal weight (Devine formula) plus 40% of the difference. Body fat needs little protein, so this avoids inflated targets.
- 2
Match the range to your situation
Losing weight, including on GLP-1 medication: 1.2–1.6 g/kg, the range the 2025 joint advisory notes for active weight loss. Losing weight and strength training: 1.4–1.8 g/kg, within the ISSN range. Maintaining: 0.8–1.2 g/kg, or 1.2–1.6 with training.
- 3
Adjust for age
From 65, the lower end rises to at least 1.0 g/kg (1.2 if you train), in line with the PROT-AGE expert group.
- 4
Keep it inside safe limits
The range never goes above 2.0 g/kg or 200 g a day (the advisory says to avoid prolonged intakes of 2 g/kg or more), and never below 50 g a day.
- 5
Split it into meals
Your range is divided across 3 to 5 meals. Aim for about 20–40 g at each, as the ISSN suggests. Smaller, more frequent portions can help on low-appetite days.
Questions
Protein calculator FAQ
How much protein do I need to lose weight without losing muscle?
Many people losing weight aim for about 1.2 to 1.6 g of protein per kg of body weight a day, and a little more if they also strength train. The calculator adjusts the weight used if your BMI is 30 or more.
Should I calculate protein from my current weight or my goal weight?
If your BMI is under 30, your current weight works well. At a BMI of 30 or above, an adjusted body weight gives a more realistic target, which is what this calculator uses.
Is this calculator suitable if I'm on Ozempic, Wegovy, Mounjaro or Zepbound?
Yes, for general education. It uses the ranges from the 2025 joint GLP-1 nutrition advisory. It doesn't change your medication or replace your prescriber's advice.
Is too much protein harmful?
For healthy adults, the ranges here are within current guidance, and the calculator caps its output at 2 g per kg and 200 g a day. If you have kidney or liver disease, don't use this calculator; ask your care team.
Do you store what I enter?
No. The calculation runs in your browser. Your answers are never sent to our servers or to analytics.
Want the exact maths? How the calculator works sets out every formula, range and cap, with its source.
Sources
- Mozaffarian D et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint Advisory from ACLM, ASN, OMA and TOS. Am J Clin Nutr 2025;122:344–367. pmc.ncbi.nlm.nih.gov
- Jäger R et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr 2017;14:20. ncbi.nlm.nih.gov
- Bauer J et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc 2013;14:542–559. pubmed.ncbi.nlm.nih.gov
- ClinCalc. Ideal body weight and adjusted body weight calculator (Devine formula). clincalc.com
Want the formulas? See exactly how the calculator works: reference weight, ranges, caps, and what it deliberately doesn't do.
General education for healthy adults, not medical advice. It is not a medical device and doesn't diagnose or treat anything.
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