GLP-1 Protein & Calorie Calculator
On Ozempic, Wegovy, Zepbound, or Mounjaro, appetite drops fast — making it easy to under-eat protein and lose muscle. This tool sets a daily protein and calorie target tuned for muscle preservation during weight loss.
Mifflin-St Jeor BMR + GLP-1 protein guidance
Educational estimate only — not medical advice. GLP-1 medications, calorie targets, and protein needs should be discussed with your prescriber, especially if you have kidney disease or other conditions. Don't drop below ~1,200 kcal/day without medical supervision.
Worked example
A 42-year-old man, 210 lb (95.3 kg), 5'8" (172.7 cm), light activity, aiming to lose weight at the recommended 1.6 g/kg protein: BMR ≈ 1,829 kcal, TDEE ≈ 2,515 kcal, calorie target ≈ 2,015 kcal (500 deficit), and a protein target of ≈ 152 g/day — about 51 g per meal across three meals.
How the calculation works
- BMR via Mifflin-St Jeor: men = 10·kg + 6.25·cm − 5·age + 5; women = 10·kg + 6.25·cm − 5·age − 161.
- TDEE = BMR × activity factor.
- Calorie target = TDEE − your chosen deficit (clamped to a 1,200 kcal floor).
- Protein = protein intensity (g/kg) × body weight in kg. On a GLP-1 deficit, 1.6–2.0 g/kg is commonly recommended to protect lean mass.
FAQ
Why higher protein on a GLP-1?
Appetite suppression makes under-eating easy, and rapid weight loss risks muscle. Higher protein + resistance training preserves lean mass.
Should I use current or goal weight?
This tool uses current body weight for a simple, safe target. Some clinicians use lean or goal weight for very high BMIs — ask your provider.
Is this calorie target safe?
It floors at 1,200 kcal, but individual needs vary. Confirm with your prescriber.
People also ask
How do I calculate how much protein I need on Zepbound?
Multiply your body weight in kilograms by a target of roughly 1.2 to 1.6 grams of protein, the range commonly cited for preserving lean mass while losing weight. An 80 kg person, for example, needs about 80 × 1.2 = 96 g to 80 × 1.6 = 128 g per day. This calculator does that math from the weight you enter; it is general information, so confirm targets with your prescriber or a dietitian.
How much protein do I need daily while on tirzepatide?
Most guidance for people losing weight on tirzepatide (Mounjaro or Zepbound) lands between 1.2 and 1.6 g of protein per kilogram of body weight per day, which is above the general adult minimum of 0.8 g/kg. Because appetite drops sharply, spreading that total across three or four meals of 25 to 40 g each makes it easier to hit. Use the calculator to get a personalized number and treat it as general information rather than medical advice.
Is 100 g of protein a day a lot?
For most adults 100 g a day is a moderate, not excessive, intake. For a 70 kg person it works out to 100 ÷ 70 ≈ 1.4 g/kg, squarely within the range recommended for preserving muscle during weight loss on a GLP-1. It is only high relative to the bare minimum of 0.8 g/kg, and healthy kidneys handle intakes in this range without difficulty; people with kidney disease should ask their doctor.