How Many Calories Should I Eat on Ozempic?

# How Many Calories Should I Eat on Ozempic?

Most people on Ozempic should aim for 1,200 to 1,500 calories a day if they're female, or 1,500 to 1,800 if they're male, though your exact number depends on starting weight, activity level, and how far along you are in treatment. Below you'll find the math to calculate your own target, real-world examples by body weight, and the warning signs that you've cut too far.

The short answer

Ozempic (semaglutide) suppresses appetite so effectively that many users naturally drop to 1,000 to 1,400 calories a day without trying. That's not automatically the right number. It's just what happens when hunger signals go quiet.

The goal isn't to eat as little as possible. It's to create a moderate deficit, roughly 500 to 750 calories below what your body burns at maintenance, while eating enough protein and total food to protect muscle, energy, and long-term metabolic health.

Calculate your own calorie target

Skip the generic "1,200 calories" advice you see everywhere online. That number was designed decades ago for average sedentary women and ignores your actual size, sex, and activity level. Here's how to get a number that fits you.

Step 1: Find your maintenance calories

Use the Mifflin-St Jeor equation, the most accurate formula for everyday use:

• Men: (10 x weight in kg) + (6.25 x height in cm) - (5 x age) + 5
• Women: (10 x weight in kg) + (6.25 x height in cm) - (5 x age) - 161

Multiply the result by an activity factor:

• Sedentary (little to no exercise): x 1.2
• Lightly active (light exercise 1 to 3 days a week): x 1.375
• Moderately active (moderate exercise 3 to 5 days a week): x 1.55

That gives your estimated maintenance calories, the amount you'd eat to hold your current weight steady.

Step 2: Subtract a deficit

Subtract 500 to 750 calories per day for a loss of roughly 1 to 1.5 pounds per week, which lines up with the pace most GLP-1 prescribers recommend. Faster isn't better here. Rapid loss on semaglutide is strongly linked to muscle loss, since the drug already blunts appetite and food intake so much that people under-eat protein without realizing it.

Step 3: Set a floor

Never go below 1,200 calories a day if you're a woman, or 1,500 if you're a man, unless a doctor or dietitian is directly supervising you. Below that floor, it becomes very hard to hit your protein target and get enough vitamins, minerals, and fiber, even from careful eating.

Example targets by starting weight

These are illustrative examples using a moderately active 40-year-old, calculated with the steps above.

• 160 lb woman, 5'5": maintenance around 1,900 calories, target range 1,300 to 1,450 calories
• 200 lb woman, 5'6": maintenance around 2,150 calories, target range 1,450 to 1,600 calories
• 180 lb man, 5'9": maintenance around 2,300 calories, target range 1,600 to 1,750 calories
• 240 lb man, 5'11": maintenance around 2,700 calories, target range 1,900 to 2,100 calories

Notice the pattern: heavier starting weights support higher calorie targets, not lower ones. A larger body burns more energy at rest, so it needs more fuel even in a deficit. Don't copy a friend's number just because you're both on Ozempic.

Why your target shifts as your dose increases

Semaglutide dosing typically escalates every four weeks (0.25 mg, then 0.5 mg, 1 mg, and up to 2 mg for Ozempic). Appetite suppression usually gets stronger at each step up, and your calorie needs change too, for two separate reasons.

• Early weeks (starting dose): appetite suppression is mild, hunger may feel close to normal, and your calculated deficit target is usually realistic and achievable.
• Mid-to-late titration: appetite drops sharply, some people struggle to reach even 1,000 calories naturally, and the risk shifts from "eating too much" to "eating too little."
• Maintenance dose, months in: your body weight is lower, so maintenance calories are lower too. Recalculate your target roughly every 15 to 20 pounds lost rather than sticking with your original number for the whole journey.

This is where most people go wrong. They set a calorie goal in month one and never revisit it, even after losing 30 or 40 pounds, which either stalls progress or drives an unintentional under-eating problem.

Signs you're eating too few calories

Because Ozempic mutes hunger cues, your body's usual warning system (feeling ravenous) often doesn't fire the way it normally would. Watch for these signs instead.

• Losing weight faster than 2 pounds a week consistently, which usually means muscle loss alongside fat loss.
• Hair thinning or shedding, a classic sign of inadequate calories and protein over several weeks.
• Constant fatigue or feeling cold, especially if it's new since starting treatment.
• Dizziness or lightheadedness when standing, which can also signal low blood sugar or dehydration.
• Irritability or difficulty concentrating, common when the brain isn't getting enough glucose or overall energy.

If two or more of these show up, add 200 to 300 calories back, prioritizing protein and fluids, and check in with your prescriber.

Prioritize protein over hitting an exact calorie number

On a suppressed appetite, the composition of your calories matters more than usual. Aim for 1.2 to 1.6 grams of protein per kilogram of body weight (roughly 0.55 to 0.75 grams per pound) to preserve lean muscle while you lose fat. This matters because studies on GLP-1 users consistently show that without enough protein, a meaningful share of total weight lost comes from muscle rather than fat, which slows metabolism over time and makes regain more likely after stopping the medication.

Practically, this means:

• Front-load protein at each small meal since appetite may not allow for three large meals anymore.
• Choose dense, high-protein foods like Greek yogurt, eggs, cottage cheese, chicken, fish, and protein shakes when volume is limited.
• Don't chase low-calorie "safe" foods that are mostly water and fiber if they crowd out protein you actually need.

Why manual tracking gets harder on Ozempic

Appetite suppression changes eating patterns in ways that make traditional food logging clunky. Meals get smaller and more frequent, portions shrink unpredictably day to day, and many users skip logging altogether because a "meal" might just be a few bites. An AI-based tracker that logs from a quick photo or description, rather than requiring you to search a database and estimate portions by hand, fits this pattern far better than typing out an entry for half a sandwich. Calchi.ai is built around exactly that kind of fast, low-effort logging, which matters most when your appetite (and your patience for detailed tracking) is running low.

Key takeaways

• Calculate your own calorie target using your weight, height, age, and activity level rather than defaulting to 1,200 calories.
• Keep a floor of 1,200 (women) or 1,500 (men) calories daily unless a doctor is supervising you closely.
• Recalculate your target every 15 to 20 pounds lost, since maintenance calories drop as your weight does.
• Prioritize protein intake over hitting an exact calorie number, since muscle loss is the bigger risk on GLP-1 medications.

FAQ

Is 1,200 calories enough on Ozempic? For many women it's a reasonable lower bound, but it's not a universal target. Taller, heavier, or more active women often need 1,400 to 1,600 calories to lose weight steadily without under-eating.

Can I eat too little while on Ozempic? Yes, and it's common. Because the drug suppresses hunger so strongly, many people drift under 1,000 calories without meaning to, which risks muscle loss, fatigue, and nutrient gaps.

Should my calorie target change as I lose weight? Yes. Recalculate roughly every 15 to 20 pounds lost, since a lighter body needs fewer calories to maintain itself, and your deficit should shrink accordingly.

Log meals with a quick photo instead of a manual search and let Calchi.ai handle the math while your appetite handles the rest.