How Many Calories Do I Need to Maintain My Weight?

Your maintenance calorie level is made up of two main components: your basal metabolic rate (BMR) — the energy your body burns at complete rest just to keep organs functioning — and the additional calories burned through movement, exercise, and daily activity. Together these give your TDEE, which is the number of calories you can eat to maintain your current weight.

Key factors that affect your number

• Body weight and composition — a larger body, or one with more muscle mass, generally burns more energy at rest.
• Age — metabolic rate tends to decline gradually with age.
• Biological sex — males typically have a higher BMR than females at the same weight, largely due to differences in muscle mass.
• Activity level — the most variable factor; someone with a physically active job or regular exercise burns significantly more than someone who is mostly sedentary.

How to estimate your maintenance calories

The most widely used method is the Mifflin-St Jeor equation, which calculates BMR from height, weight, age, and sex, then multiplies it by an activity factor (ranging from roughly 1.2 for sedentary to 1.9 for very active). The result is an estimate — real-world energy expenditure varies day to day, and factors such as recent weight loss, illness, or changes in activity can shift your number meaningfully. Treat it as a useful starting point rather than a fixed target.

Why this matters on a GLP-1 medication

Mounjaro (tirzepatide) and Wegovy (semaglutide) commonly reduce appetite and what many people describe as "food noise". This can mean eating far fewer calories than your body actually needs to maintain lean muscle and energy levels — particularly if protein intake drops alongside overall food volume. Knowing your approximate maintenance figure helps you eat intentionally rather than accidentally under-fuelling. If you want to explore related tracking topics, see our guides on what a calorie maintenance level means in practice and understanding how much you eat in a typical day.

For a broader look at calorie numbers and how to use them on your journey, visit our calorie calculator hub.

Calculating a maintenance number is only useful if you can see how your actual intake compares to it every day — and that is where consistent logging makes all the difference.

GLP Trackr's AI food photo scan is the quickest way to do this when appetite is low and meal sizes are small. Point your camera at a plate and the app estimates calories, protein, and macros in seconds — no manual searching required. You can also log via barcode scan or a standard food search if you prefer.

Once your calorie target is set in the app, the daily check-in brings together your food log, weight, energy, and mood in one place, so you can see at a glance whether you are eating close to your maintenance level or significantly below it. Over time, the insights and analytics features show patterns in your data — for example, how days when you eat close to your protein goal relate to your energy levels or weight trend. This kind of personal data is also useful to bring to appointments, helping you have a more informed conversation with your prescriber or doctor. You can read more about tracking what you eat day-to-day in our guide to understanding calorie counts.

General educational calorie figures are a helpful guide, but any personalised nutrition targets — especially if you have an underlying health condition or are managing your weight as part of a treatment plan — should be discussed with your healthcare professional, who knows your full history.

Ready to see how your daily intake compares to your maintenance level? Download GLP Trackr on the App Store or Google Play and log your first meal free — your 7-day trial starts the moment you open the app.