GLP-1 Calorie Calculator

Eating too little on a GLP-1 is a real problem. If you consistently go below about 1,200 calories per day (women) or 1,500 calories per day (men), you risk losing muscle instead of fat, developing nutrient deficiencies, and experiencing hair thinning or fatigue. GLP-1 medications can suppress your appetite so strongly that some people are not eating enough without realizing it. This calculator shows a warning if your result hits the minimum floor so you can flag it with your prescriber.

Aim for 1.2 to 1.5 grams of protein per kilogram of body weight per day. At 80 kg (176 lb), that works out to roughly 96 to 120 grams of protein per day. That range comes from research on preserving muscle during the rapid weight loss that GLP-1 medications cause. This calculator uses your body weight to set that target and shows the number in grams alongside your calorie result.

Start with two numbers: total calories and total protein. Protein protects your muscle while the drug reduces your calorie intake. Once you are consistently hitting your protein target and staying above the calorie floor, the split between fat and carbs matters much less. If you want a more detailed breakdown, a registered dietitian who works with GLP-1 patients can help.

The drug handles some of the work by reducing your appetite, but it does not guarantee you will hit an optimal calorie or protein target. Many people on GLP-1 eat too little protein or fall below the calorie floor without realizing it. Tracking gives you visibility into both, which is why this calculator includes a protein target alongside the calorie number.

Pick the level that matches your average week, not your best or worst week. Sedentary means a desk job with little or no deliberate exercise. Moderate means structured exercise three to five days per week. If you have a physically demanding job and also exercise, choose Extra active. When in doubt, go one level lower than you think. Most people overestimate their activity.

A standard TDEE calculator gives you your maintenance calories and stops there. This calculator adds a GLP-1 adjustment: a 20% reduction from your TDEE to reflect the typical intake reduction from semaglutide and tirzepatide, a protein target based on your body weight to protect muscle mass, and a minimum calorie floor with a warning if your result falls below it.

Yes. Wegovy and Ozempic are brand names for semaglutide. Mounjaro and Zepbound are brand names for tirzepatide. The GLP-1 adjustment this calculator applies is based on the intake reduction seen across trials for both drugs, so the result applies regardless of which brand you are using.

Ozempic is a brand name for semaglutide, so the same approach applies. A good starting point is roughly 20% below your maintenance calories, which lines up with what the clinical trials show for Ozempic users. Use the calculator above to get your personal number based on your height, weight, age, and activity level. Your prescriber should review the result before you commit to it.

Mounjaro and Zepbound are brand names for tirzepatide. The calorie approach is the same as with semaglutide: roughly 20% below your maintenance level, with a minimum calorie floor to protect against deficiencies. Tirzepatide tends to suppress appetite more strongly than semaglutide in clinical trials, so some people end up eating well below their target. If that is happening to you, tell your prescriber rather than pushing yourself to eat even less.

Mifflin-St Jeor is a widely used formula for estimating basal metabolic rate (BMR), which is the number of calories your body burns at rest. It uses your sex, age, weight, and height. This calculator uses Mifflin-St Jeor because it is consistently rated as the most accurate general-purpose BMR formula in clinical nutrition research, outperforming older formulas like Harris-Benedict in independent validation studies.