GLP-1 Calorie Calculator
Find out how many calories to eat daily on semaglutide, tirzepatide, Wegovy, Ozempic, Zepbound, or Mounjaro. Enter your measurements to see your personal calorie target for safe weight loss — including the minimum you should never go below. Built for GLP-1 patients, not the general population.
Standard calorie calculators tell you to eat less. GLP-1 medications already do that. The real question is how much to eat to protect your muscle while the medication handles appetite suppression.
GLP-1 medications significantly reduce appetite in many patients. That’s the mechanism — and it’s powerful. But when total calorie intake drops too low, the body begins breaking down muscle for energy. That’s not fat loss. It’s metabolic regression that makes long-term maintenance harder.
The STEP 1 and SURMOUNT-1 trials — the pivotal clinical trials for semaglutide and tirzepatide — used a 500 calorie daily deficit as the dietary protocol.[1][2] That’s the evidence-backed target. The goal isn’t to eat as little as possible — it’s to eat enough to protect your muscle while the medication handles the rest. Research shows that a 500 kcal deficit does not meaningfully increase muscle loss when protein targets are met.[4]
Patients often come in having lost 3–5 pounds in a week and ask if it’s time to increase their dose. At Rivas, the answer is usually no — and that’s intentional.
Rapid early losses are common on GLP-1 medications. They don’t mean more is better — they mean the medication is working. Pushing the dose higher when a patient is already losing consistently doesn’t accelerate results. It increases side effects, suppresses appetite further than necessary, and can actually stall progress by driving calorie intake below the safe floor.
At Rivas, every dose decision is made by a licensed provider who knows your full picture — your rate of loss, your body composition, your side effect profile, and your long-term goals. We know when to hold a dose, when to move forward, and when stepping back is the right clinical move.
Ashley DeLashmutt PA-C
Rivas Hagerstown
“I have often seen when dosages are pushed too high, a patient has little to no appetite — and then weight loss slows due to inadequate caloric intake.”
A calorie calculator gives you a number. A Rivas provider gives you a plan that adjusts as your body changes — so you lose the right weight, at the right pace, without losing the muscle that keeps your metabolism working.
How many calories should I eat on Wegovy?
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It depends on your body — which is exactly why a calculator matters more than a generic number. The clinical trials that studied Wegovy (semaglutide) used a 500 calorie daily deficit as the dietary target. For most patients that works out to roughly 1,500–1,800 calories per day, but your specific number depends on your weight, height, age, sex, and activity level. Use the calculator above to find your personal target.
How many calories should I eat on Ozempic?
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Ozempic contains the same active ingredient as Wegovy (semaglutide) and works through the same appetite-suppression mechanism. The same calorie principles apply: a 500 calorie daily deficit from your maintenance level is the evidence-backed target. Because Ozempic is primarily prescribed for type 2 diabetes management, your provider may have additional dietary guidance specific to your situation — always follow their recommendation alongside this calculator.
How many calories should I eat on Zepbound or tirzepatide?
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The SURMOUNT-1 trial — the pivotal clinical trial for tirzepatide (Zepbound, Mounjaro) — used the same 500 calorie daily deficit protocol as the semaglutide trials. So the target is the same: 500 fewer calories per day than your body burns. The calculator above works for all GLP-1 medications including tirzepatide. Your calorie target is determined by your body and activity level, not which specific medication you’re taking.
How many calories should I eat on Mounjaro?
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Mounjaro contains tirzepatide — the same medication as Zepbound — and works through the same mechanism. The calorie target is the same: approximately 500 fewer calories per day than your body burns at your current activity level. Enter your measurements above to get your specific number. The calculator works for Mounjaro patients at any dose.
How do I avoid muscle loss on semaglutide or Ozempic?
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The two most important levers are protein intake and resistance training — not further calorie restriction. Aim for 1.2–1.6 grams of protein per kilogram of body weight per day, and incorporate resistance training at least 2–3 times per week. The calorie floor shown in this calculator is also critical: GLP-1 medications can suppress appetite enough that patients unknowingly eat too little, which accelerates muscle breakdown. Staying above your minimum and hitting your protein target does more for muscle preservation than any specific calorie number.
What happens if I don’t eat enough on semaglutide?
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Eating too little is one of the most common and underrecognized problems on GLP-1 medications. When appetite suppression is strong, some patients eat well below 1,000 calories a day without realizing it. Sustained restriction at that level leads to muscle loss, hair thinning (telogen effluvium), fatigue, and nutritional deficiencies — and makes long-term weight maintenance harder because it reduces your metabolic rate. If your appetite is consistently pushing you below the floor shown in the calculator, tell your Rivas provider. A dose adjustment may be the right move.
How much protein should I eat on semaglutide or tirzepatide?
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Most obesity medicine guidelines recommend 1.2–1.6 grams of protein per kilogram of body weight per day for patients on GLP-1 medications — higher than the general population recommendation. This is specifically to offset the muscle loss risk that comes with rapid weight loss. Use the Rivas Protein + Water Calculator to find your exact daily protein target based on your current weight.
My GLP-1 medication is already suppressing my appetite — do I still need to track calories?
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Not necessarily — but knowing your floor is important. GLP-1 medications can suppress appetite so effectively that some patients eat far too little without realizing it. The calculator isn’t asking you to hit a precise number at every meal — it’s giving you a target range to stay within and a floor not to drop below. If you’re eating intuitively and feeling good, that’s fine. If you’re feeling fatigued, losing hair, or losing strength, your intake may be too low.
Why do calorie targets change as I lose weight?
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As you lose weight, your body burns fewer calories at rest — it has less mass to maintain. This is why weight loss naturally slows over time even when you’re doing everything right. Recalculating monthly keeps your targets accurate as your body changes. If you have access to an InBody scan at Rivas, using your measured BMR rather than the formula estimate is more accurate still — it captures actual changes in muscle mass, which drives metabolism more than scale weight alone.
I’m hitting a plateau. Should I cut calories further?
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Not usually — and cutting further can make things worse. Plateaus on GLP-1 medications are normal and often reflect metabolic adaptation rather than insufficient calorie restriction. Adding or increasing resistance training, adjusting protein intake, or discussing a dose adjustment with your Rivas provider are more productive levers. Chasing a deeper deficit on top of what the medication is already doing is usually counterproductive and increases muscle loss risk.
What is the InBody scan number and where do I find it?
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InBody is a body composition device that measures lean mass, body fat percentage, and your actual basal metabolic rate using bioelectrical impedance. Your InBody BMR is labeled “Basal Metabolic Rate” on your printout — typically a 4-digit number between 1,200 and 2,000 kcal/day. Using this number in the calculator instead of the formula estimate gives you a more accurate calorie target because it’s based on your actual muscle mass, not population averages.
