Protein calculator
Protein calculator
How much protein per day to protect muscle while you lose fat — set from your body weight, not a percentage. Tuned for GLP-1 users, where low appetite makes protein easy to miss.
Aim for about 164 g/day — roughly 41 g per meal across four eating occasions. Protein provides 4 kcal per gram, so that is about 656 kcal from protein.
In a calorie deficit — and especially on a GLP-1, where appetite drops fast — aim for the upper end. This is the range that preserves lean mass while you lose fat. Protein is anchored to body weight because a percentage-of-calories target shrinks as your calories fall — exactly when muscle is most at risk. Hit the number first each day; on low-appetite days a shake or Greek yogurt closes the gap fastest.
How the target is set
The calculator multiplies your body weight in kilograms by an evidence-based factor for your goal. For fat loss and muscle building that factor is roughly 1.6 to 2.2 g/kg — the range associated with preserving or adding lean mass. For weight maintenance it drops to about 1.2 to 1.6 g/kg. Protein is anchored to weight rather than a share of calories because a percentage target shrinks as your calories fall, exactly when muscle is most vulnerable in a deficit.
Why protein comes first on a GLP-1
Appetite suppression is how GLP-1 medications work — and it is also why users so often fall short on protein. A meaningful share of GLP-1 weight loss can be lean mass, and low protein plus rapid loss makes that worse. Prioritize the protein number even on days you eat little else, pair it with resistance training, and let carbs flex down when appetite is low. See the macro calculator to build the rest of your day around this protein floor, or the calorie deficit calculator for your calorie target.
Protein calculator FAQ
How much protein do I need per day to lose weight?+
In a calorie deficit, aim for about 1.6 to 2.2 grams of protein per kilogram of body weight — roughly 0.7 to 1.0 gram per pound. That range is what the evidence links to preserving lean mass while you lose fat. A 90 kg (198 lb) person targets about 145 to 200 grams a day. Hit the number consistently rather than chasing a perfect ratio.
Why does protein matter more on Wegovy or Zepbound?+
GLP-1 medications suppress appetite quickly, so many users unintentionally eat far too little protein. Combined with fast weight loss, low protein pushes more of that loss toward muscle instead of fat. Muscle drives your resting metabolism and strength, so protecting it protects both your results and your ability to keep the weight off. Treat protein as the non-negotiable daily target.
Should protein be based on body weight or a percentage of calories?+
Body weight. A percentage-based target falls as your calories fall — exactly when you are cutting and need protein most to protect muscle. Anchoring protein to body weight keeps it high and stable no matter how low your calorie target goes, which is why this calculator uses grams per kilogram.
How do I hit a high protein target when I have no appetite?+
Front-load it. Eat protein earliest in the day when appetite is highest, lean on fast, low-volume sources — Greek yogurt, a whey or protein shake, eggs, cottage cheese, chicken or fish — and split the total across your meals so no single sitting feels overwhelming. A shake can add 25 to 40 grams with almost no fullness cost on a hard day.
Can too much protein be harmful?+
For people with healthy kidneys, intakes in the 1.6 to 2.2 g/kg range studied for muscle preservation are considered safe. If you have chronic kidney disease or another condition that restricts protein, talk to your clinician before raising your intake — the general guidance here is not tailored to those situations.
Sources
Protein for lean-mass preservation and muscle: Morton RW, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength. Br J Sports Med. 2018;52(6):376-384. PMID: 28698222. Higher-protein intake during energy restriction: Helms ER, et al. A systematic review of dietary protein during caloric restriction in resistance-trained lean athletes. Int J Sport Nutr Exerc Metab. 2014;24(2):127-138. PMID: 24092765.
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