Calorie Requirement Calculator: Understanding Your Daily Needs on a GLP-1 Medicine

Your daily calorie requirement is an estimate of the total energy your body needs over 24 hours to support everything it does — from breathing and circulation to movement and digestion. It is commonly calculated in two stages: first, a basal metabolic rate (BMR), which reflects the calories your body burns at complete rest, and second, an activity multiplier that accounts for how much you move throughout the day. The combined figure is often called your total daily energy expenditure (TDEE).

Why this matters on a GLP-1 medicine

Reduced appetite is one of the most commonly reported effects of GLP-1 receptor agonist medicines. While eating less can support the goals many people have when prescribed these treatments, eating far too little — particularly in protein — can make it harder to preserve muscle, maintain energy, and feel well. Understanding your calorie requirement helps you stay in a sensible range rather than accidentally under-fuelling.

General educational guidance suggests that most adults need somewhere between roughly 1,500 and 2,500 calories per day depending on body size and activity, but this varies widely. A personalised estimate from this calculator gives you a more relevant number to work from. For food choices that sit well on a GLP-1 medicine, see our guide on tracking your daily calorie intake and how those figures connect to your overall targets.

How the calculation works

The most widely used formula for estimating BMR is the Mifflin-St Jeor equation, which takes into account weight, height, age, and biological sex. An activity factor is then applied — ranging from sedentary (little or no exercise) to very active (hard physical work or training most days). The result is an estimate, not a precise prescription; individual metabolism varies, and factors like body composition, medication, and health conditions all influence actual energy needs.

If you want to compare this figure with the number of calories needed simply to maintain your current weight, our maintenance calorie calculator covers that in more detail. Both feed into a broader picture of how to approach food on your GLP-1 journey — you can explore that fuller picture at our calorie calculator hub.

Calculating your daily calorie requirement is the first step — hitting it consistently day after day is where most people find things get tricky, especially when appetite fluctuates week to week on a GLP-1 medicine. GLP Trackr's AI food photo scan is the fastest way to close that gap: point your camera at a meal and the app estimates calories, protein, and macros instantly, without manual searching or guesswork.

Once you know your calorie requirement, you can set it as a daily target inside the app. Every meal you log — whether by photo scan, barcode, or search — counts toward that target in real time, so you always know where you stand. The app also tracks protein separately, which matters because getting enough protein on a reduced appetite is one of the most common challenges people on GLP-1 medicines talk about.

Over time, the insights feature surfaces patterns from your own data — for example, whether the days you hit your calorie and protein targets align with better energy or faster progress. That kind of personalised picture is genuinely hard to build without consistent logging.

GLP Trackr is available free on the App Store and Google Play, with a 7-day free trial so you can explore every feature before committing. Start logging your meals today and see how your daily intake stacks up against your calorie requirement.

The figures from any calculator are general estimates and are not a substitute for personalised advice. If you have questions about the right calorie intake for your specific situation — particularly alongside a prescribed medicine — always discuss them with your prescriber or doctor, who knows your full health history.