How Many Calories Should I Eat in a Day?

Your daily calorie requirement starts with your Total Daily Energy Expenditure (TDEE) — the total calories your body uses across the day, including at rest and during activity. TDEE is built from two components:

• Basal Metabolic Rate (BMR): the calories your body needs to keep basic functions running — breathing, circulation, cell repair — even at complete rest. This alone accounts for roughly 60–75% of most people's daily calorie use.
• Activity factor: calories burned through movement, from a desk job with a short daily walk through to physical labour or structured exercise.

A commonly used approach is to estimate BMR using a formula such as Mifflin-St Jeor, then multiply it by an activity factor to reach TDEE. You can explore this calculation on our calorie calculator hub or look at guidance on general calorie needs for more background.

Calories in a deficit

If you are aiming to eat in a calorie deficit, a moderate reduction — often cited in general nutrition guidance as roughly 300–500 calories below TDEE — is associated with gradual, sustainable weight loss. Eating too far below your needs can reduce energy, affect protein intake, and make it harder to maintain muscle. There is no single correct deficit figure; what matters is that any target feels manageable, keeps protein intake adequate, and is agreed with your healthcare professional if you have any medical considerations.

How many calories at breakfast?

There is no fixed rule for how calories should be split across meals. Many people find that on a GLP-1 medicine, appetite varies significantly across the day, and a rigid breakfast target can feel unhelpful. A practical approach is to anchor protein at each meal and let total calories follow, rather than working backwards from a per-meal quota. If you are curious about a more detailed breakdown, see daily calorie guidance or read about calorie targets specifically on Mounjaro.

GLP-1 medicines and appetite

Mounjaro (tirzepatide) and Wegovy (semaglutide) act on appetite-regulating pathways, and many people report a reduced sense of hunger — sometimes called lower food noise — particularly around dose increases. This can make it easier to eat less, but it also makes it important to ensure that what you do eat is nutritionally dense, with enough protein to support muscle and enough calories to sustain your energy. Eating significantly below your needs unintentionally is worth tracking and discussing with your prescriber or doctor.

Counting calories manually can feel tedious, especially when appetite is unpredictable. GLP Trackr's AI food photo scan is the fastest way to log what you eat — point your camera at a meal and get an instant breakdown of calories, protein, and macros without typing a single thing. For packaged foods, the barcode scanner works just as quickly.

Once you set a daily calorie target in the app, GLP Trackr tracks your intake against it in real time, so you always know where you stand without doing the arithmetic yourself. You can also set a protein target separately — useful for making sure a reduced appetite does not mean reduced protein — alongside goals for water, fibre, and steps.

Over time, the app's insights help you see how your food intake relates to your weight trend and energy levels, giving you data worth discussing at your next prescriber appointment rather than guesswork. The doctor report feature can summarise your nutrition and progress in a format you can share directly.

GLP Trackr is free to try for 7 days — available on the App Store and Google Play. Set your calorie and protein targets, snap your first meal, and let the app do the tracking from there.

The calorie ranges on this page are general educational guidance. The right intake for you — especially if you have any medical conditions or are taking other medicines — is a conversation to have with your prescriber or doctor, who knows your full picture. GLP Trackr helps you record what you eat so you can have that conversation with real data.