GLP-1 Calorie & Protein Calculator — Ozempic, Wegovy, Mounjaro & Zepbound

How many calories should you eat on a GLP-1?

Short answer: there is no single number, and chasing one is the wrong goal. Because the medication leads your appetite, you will usually land 500–900 kcal below maintenance without forcing it. The two things worth tracking are (1) hitting a protein target that protects muscle and (2) staying above a safe daily floor — about 1,200 kcal/day for women and 1,500 kcal/day for men, and never below your BMR for long without medical supervision. This calculator gives you your personal maintenance range and protein target so you have both guardrails.

How much protein on Ozempic, Wegovy, Mounjaro, or Zepbound?

Aim for about 1.2–1.6 g of protein per kg of body weight per day (roughly 0.55–0.73 g per lb), toward the higher end if you lift. The 2025–2030 U.S. Dietary Guidelines support higher protein during weight loss to preserve lean mass. The hard part on a GLP-1 is mechanical — low appetite makes it tough to physically eat enough — so lean on protein-dense, low-volume foods: Greek yogurt, cottage cheese, eggs, rotisserie chicken, edamame, and a protein shake when a meal feels like too much. "Protein first" at every meal is the single most useful habit on these medications.

Why muscle preservation is the real GLP-1 risk

Rapid weight loss always includes some lean-mass loss, and clinical trials of GLP-1 medications found a meaningful share of total weight lost can come from muscle when protein and resistance training aren't prioritized. Muscle is metabolically expensive tissue — losing it lowers your maintenance metabolism and makes weight easier to regain when you taper off. The two protective levers are simple and evidence-based: eat enough protein (~1.2–1.6 g/kg/day) and do resistance training 2–3× per week. Everything this tool and the NanoRhino coach do is built around those two levers.

How it works

1. Tell the AI you're on a GLP-1 and what you're after — losing fat while keeping muscle, recomp, or maintaining/tapering off. It asks a few short questions about your body and typical day.
2. The AI submits a structured profile to a deterministic calculation function. The AI never does the math itself.
3. You get a calibrated maintenance-calorie range (BMR + NEAT + TEF + EAT), a muscle-preserving protein target, and a safe floor — framed for appetite-led eating, not a forced deficit.
4. Optionally, text it to the NanoRhino AI coach to get a saved plan and day-to-day support through dose changes and the taper.

Frequently asked questions

How many calories should I eat on Ozempic, Wegovy, or semaglutide?

There is no single "Ozempic calorie number." Because semaglutide suppresses appetite, most people naturally eat well below their maintenance calories — the goal is not to force a deficit but to make sure you do not under-eat. This calculator estimates your maintenance (TDEE) from a short interview, then frames it as a ceiling, not a target: eat to your appetite, keep protein high, and do not drop below the safe daily floor of about 1,200 kcal for women or 1,500 kcal for men without medical supervision.

How many calories should I eat on Mounjaro or Zepbound (tirzepatide)?

The same principle applies to tirzepatide as to semaglutide: appetite leads intake, so the priority is hitting your protein target and staying above a safe minimum, not counting down to a calorie goal. The calculator computes your individual maintenance range; on a GLP-1 you will usually land 500–900 kcal under it on your own. Re-check the number after each dose change or every ~10 lb lost, since maintenance falls as you lose weight.

How much protein should I eat on a GLP-1?

Aim for roughly 1.2–1.6 g of protein per kg of body weight per day (about 0.55–0.73 g per lb), and toward the upper end if you are lifting. The 2025–2030 U.S. Dietary Guidelines support a higher protein intake during weight loss to protect lean mass. On a GLP-1 the challenge is mechanical — appetite is low — so "protein first" tactics (Greek yogurt, cottage cheese, eggs, rotisserie chicken, a protein shake) help you hit the target even on small portions.

Why is muscle loss a risk on GLP-1 medications?

Whenever you lose weight quickly, some of the loss is lean mass, not just fat. In clinical trials of GLP-1 medications a meaningful share of total weight lost came from lean mass when protein and resistance training were not emphasized. The two protective levers are well established: eat enough protein (about 1.2–1.6 g/kg/day) and do resistance training 2–3x/week. That is the entire premise of this calculator — keep the weight you lose as fat, not muscle.

Should I count calories on a GLP-1 if I am barely hungry?

You usually do not need to chase a calorie target — the medication already drives the deficit. What is worth tracking is protein (to hit the muscle-preserving target) and a daily minimum (so you do not under-eat on days when food noise is gone). This tool gives you both: a calibrated maintenance number and a protein target, plus a floor to stay above.

What is the minimum number of calories I should eat on a GLP-1?

As a general safety floor, do not eat below about 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision — and never below your basal metabolic rate (BMR) for extended periods. Some people on GLP-1s self-impose floors that are too low because appetite is suppressed; eating too little costs muscle, energy, and adherence. If you consistently cannot reach the floor, that is worth raising with your prescriber.

Does this calculator work for retatrutide or compounded GLP-1s?

Yes. The math is the same regardless of which GLP-1 you are on — semaglutide, tirzepatide, liraglutide, dulaglutide, or an investigational or compounded agent such as retatrutide. The calculator estimates your maintenance calories and protein target from your body and activity; it does not depend on the specific drug or dose, and it never gives dosing advice.

How is TDEE different when you are on a GLP-1?

Your Total Daily Energy Expenditure (TDEE — the calories your body burns in a day) is calculated the same way on or off a GLP-1: BMR + daily movement (NEAT) + the thermic effect of food (TEF) + exercise (EAT). What changes is how you use it. Off a GLP-1, you subtract a deficit from TDEE. On a GLP-1, appetite already creates the deficit, so TDEE is best read as a maintenance ceiling and a sanity check that you are not eating dangerously little.

What should I eat when I taper off a GLP-1?

As the medication leaves your system, appetite returns — which is exactly when many people regain weight. The transition is easier if you have built a protein habit and kept your muscle during the loss phase, because more muscle means a higher maintenance metabolism. Re-running this calculator at your new lower weight gives you an updated maintenance number to hold, and NanoRhino's coach is built to support the taper specifically.

Is this medical advice?

No. This is an educational calorie and protein calculator, not medical advice, and it does not provide dosing guidance. GLP-1 medications should be managed with your prescriber. Always talk to a healthcare professional about your medication, your calorie floor, and any symptoms.

Sources

• Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med. 2021;384:989–1002.
• Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med. 2022;387:205–216.
• U.S. Departments of Agriculture and Health and Human Services. Dietary Guidelines for Americans, 2025–2030.
• Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure. Am J Clin Nutr. 1990;51(2):241–7.
• Ainsworth BE, et al. 2011 Compendium of Physical Activities. Med Sci Sports Exerc. 2011;43(8):1575–81.