How to Calculate How Many Calories to Eat on Your GLP-1 Journey

Your daily calorie needs are shaped by two things: your basal metabolic rate (BMR) — the energy your body burns at complete rest — and your activity level, which scales that number up to reflect how much you actually move. Multiply the two together and you get an estimate of your total daily energy expenditure (TDEE). To lose weight gradually, most approaches involve eating a modest amount below that figure; to maintain weight, you eat roughly at it.

The main factors in the calculation

• Body weight and height — heavier or taller bodies generally have higher BMRs.
• Age — metabolic rate tends to decrease gradually over the decades.
• Sex assigned at birth — influences baseline calorie needs in most standard formulas.
• Activity level — from largely sedentary to highly active; this multiplier has a significant effect on the final number.

Common formulas used in calculators (such as Mifflin-St Jeor) combine these factors to produce an estimate. It is worth remembering that any formula produces an estimate, not a precise prescription — individual metabolism varies, and the number is a starting point to refine over time.

What changes on a GLP-1 medicine

Many people taking Mounjaro or Wegovy find their appetite decreases noticeably, sometimes to the point where hitting even a modest calorie target feels difficult. Protein intake in particular can slip when appetite is low, which matters because preserving muscle during weight loss is important. Tracking your actual intake against your calculated target helps you spot this pattern early — something worth discussing with your prescriber or a registered dietitian. For more on the relationship between calories and weight change, see how many calories make up a pound of body weight, and for a broader look at what calories actually are, understanding calories is a useful starting point.

If you want guided help working out your personal number, our GLP-1 calorie calculator walks through the key inputs for you. You can also explore other ways to figure out your calorie needs for additional context on the approaches available.

Knowing your calorie target is one thing; consistently tracking against it — especially when GLP-1 appetite changes make meals irregular — is where most people find the real challenge. GLP Trackr's AI food photo scan is the feature built directly for this: point your camera at a meal and the app estimates the calories, protein, and macros instantly, with no manual searching required. On days when appetite is low and meals are small, the friction of logging needs to be close to zero.

Once your calorie goal is set in the app, your daily targets dashboard keeps a running total throughout the day — so you can see at a glance whether you are on track, under, or have room for more. Alongside calories, you can set a protein target separately, which many people on GLP-1 medicines find particularly useful for staying on top of muscle-preserving intake when hunger signals are quiet.

The app's insights can also surface patterns over time — for example, whether days with higher protein intake correlate with better energy or faster progress. That kind of personal data is genuinely useful to bring to a conversation with your prescriber or a dietitian.

Any specific calorie target should be agreed with your healthcare professional, who can factor in your full medical history and any other medicines you take. GLP Trackr helps you log and track consistently — it is not a substitute for that clinical guidance.

Ready to put a number to your daily goal and actually hit it? Download GLP Trackr on the App Store or Google Play and get started with a free 7-day trial — no commitment needed.