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Informational only. This calculator doesn’t give medical advice. GLP-1 medications are prescription drugs: follow your prescriber’s and dietitian’s guidance on diet, protein and fluids, especially if you have kidney disease or another medical condition.
How the GLP-1 protein calculator works
The numbers come from a 2025 joint advisory by the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society, published in Obesity:
- Daily range: 1.2 to 1.6 g of protein per kg of a reference weight, the range the advisory notes has been proposed during active weight reduction.
- Reference weight: your current weight, or your goal weight if you choose to use it. The advisory explains that for people with obesity, actual weight can significantly overestimate protein needs, and that adjusted or ideal weight (or lean mass) may be used instead.
- Per meal: your range divided by the number of meals or snacks you usually have.
- A simpler alternative: an absolute target of 80 to 120 g a day, which the advisory suggests may help with adherence.
- Bounds: intake shouldn’t fall below the adult RDA of 0.8 g per kg, and the advisory recommends avoiding prolonged intakes at or above 2 g per kg a day.
The same 1.2 to 1.6 g per kg range also appears in the Dietary Guidelines for Americans, 2025–2030 as the general protein goal for adults.
Why protein deserves extra attention
GLP-1 medications reduce appetite, which is part of how they work. Eating less overall also makes it easier to fall short on protein. The advisory reports that in the STEP 1 trial of semaglutide, of an average weight reduction of 13.6 kg, 8.3 kg (62%) was fat mass and 5.3 kg (38%) was lean body mass. Keeping protein up, together with regular strength training, is one of the advisory’s priorities for preserving muscle and bone.
Practical ways to reach your range
- Protein first. Start meals with the protein part while your appetite is strongest.
- Smaller, more frequent meals. The advisory notes these can help with nausea; four or five small protein-containing meals or snacks often work better than three large ones.
- Easy, soft options. Greek yogurt, cottage cheese, eggs, tofu, fish, lentil soups and milk-based drinks are gentle when appetite is low.
- Fluids and fiber. Drink regularly and include fiber from foods, which the advisory recommends to help with constipation.
- Move, and lift. The advisory recommends pairing GLP-1 treatment with structured exercise: strength training at least three times a week plus at least 150 minutes of moderate aerobic activity.
A worked example
Someone who weighs 100 kg with a goal of 80 kg, eating four times a day:
- Using the goal weight: 1.2 × 80 = 96 g to 1.6 × 80 = 128 g a day
- Per meal: about 24 to 32 g
- Lower bound (0.8 g per kg): about 64 g a day
- Avoid staying above (2 g per kg): about 160 g a day
Tracking protein in Calorix
Calorix shows the protein in every meal you log, by photo, barcode, voice or text, and how much is left for the day. You can set a custom protein target agreed with your care team, and smaller meals are just as quick to log as big ones. Our article on GLP-1 medications and protein goes deeper into food ideas and the research.
Updated October 9, 2026
