Tool · Protein per day
Protein calculator.
How much protein a day while losing weight on a GLP-1?
A 2025 joint advisory from four US societies in lifestyle medicine, nutrition and obesity notes that the general adult allowance is 0.8 g of protein per kg of body weight a day, and that 1.2–1.6 g/kg has been proposed during active weight loss. It also offers 80–120 g a day as a simpler target. Your clinician can tailor it.
Updated
Worked out from 85 kg. Using total body weight can overestimate protein needs in larger bodies; a clinician or dietitian may base it on an adjusted weight or lean mass instead.
Per meal
| Range | A day | Each of 3 meals | Each of 4 meals |
|---|---|---|---|
| 1.2–1.6 g per kg | 102–136 g | 34–45 g | 26–34 g |
| 0.8 g per kg | 68 g | 23 g | 17 g |
| Fixed 80–120 g | 80–120 g | 27–40 g | 20–30 g |
The advisory gives amounts for the whole day, not per meal. This splits the day’s range evenly and rounds to whole grams. Spreading it differently is fine.
If your appetite is small
The advisory notes that a smaller appetite or changes in taste on a GLP-1 can make protein hard to reach. Its practical suggestions:
- Eat the protein part of a meal first.
- Choose protein foods that don’t take up much room, such as fish, eggs, Greek yogurt, cottage cheese, and nuts and seeds or their butters.
- Have regular, small meals at consistent times rather than large meals or long gaps.
- Some people use high-protein shakes, bars or fortified foods to reach their target.
It also says protein alone is unlikely to protect muscle without strength (resistance) training.
Ranges from a published advisory, worked out from the weight you entered. This isn’t a personal recommendation. If you have kidney disease or another health condition, ask your clinician before changing how much protein you eat.
Where the numbers come from
One advisory, four ways to set a target.
The figures come from “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, published in May 2025. Mozaffarian et al., Obesity, 2025.
It gives four ways to set a daily target: 0.8 g per kg of body weight (the general adult allowance), 1.2–1.6 g per kg (proposed during active weight loss), 1.5 g per kg of fat-free mass, and a fixed 80–120 g.
The advisory says it is unclear whether targets should use actual body weight, an adjusted or ideal weight, or fat-free mass, and that actual weight can significantly overestimate needs. It says estimated fat-free mass “may be best”, though there is still no consensus, and that 1.5 g per kg of fat-free mass needs body-composition data to work out. This calculator only has your weight, so it shows the two per-kilogram ranges and the fixed 80–120 g option, not the fat-free-mass target.
Why it matters on a GLP-1: some of the weight lost in trials is lean mass. In the SURMOUNT-1 body-composition substudy it was about a quarter. See GLP-1 by the numbers.
Method
How this works.
- Inputs
Your body weight in kilograms, pounds, or stones and pounds, and whether you eat 3 or 4 meals a day. Nothing is stored or sent anywhere.
- Formula
Weight is converted to kg (1 lb = 0.45359237 kg; 1 stone = 14 lb). Then: weight × 0.8 g, weight × 1.2 g to weight × 1.6 g, and the fixed 80–120 g a day. Each is rounded to whole grams.
Per meal = the daily amount ÷ the number of meals, rounded. The advisory doesn’t set per-meal amounts; this is an even split.
- Sources
Mozaffarian et al., “Nutritional priorities to support GLP-1 therapy for obesity”, a joint advisory from four US societies, Obesity, May 2025 (correction April 2026). The small-appetite tips are from the same advisory. Checked 26 October 2026.
- Limits
The advisory says it isn’t clear whether targets should use actual weight, an adjusted or ideal weight, or lean mass, and that actual weight can significantly overestimate needs in larger bodies. It also says intake shouldn’t fall below 0.4–0.5 g/kg a day and that long-term intake at or above 2 g/kg a day should be avoided. Only weights between 30 and 350 kg (67 to 771 lb, or 4 st 11 lb to 55 st 1 lb) are calculated.
- What this is not
Not a personal protein target, a meal plan or medical or dietary advice. It doesn’t account for kidney disease, pregnancy, age or other conditions. Ask your clinician, dietitian or pharmacist.
Sources
- Mozaffarian D, et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory. Obesity (Silver Spring) 2025;33(8):1475–1503Also published in the American Journal of Clinical Nutrition 2025;122(1):344–367. A correction was published in Obesity in April 2026.
- Look et al., Diabetes, Obesity and Metabolism, 2025 (SURMOUNT-1 DXA substudy)About 26% of weight lost on tirzepatide was lean mass.
This calculator does arithmetic on published ranges. It isn’t medical or dietary advice. Talk to your clinician, dietitian or pharmacist about what is right for you.