How to Work Out Your Maintenance Calories on a GLP-1 Journey

Maintenance calories represent the balance point between energy in and energy out. Eat at that level consistently and, all else being equal, body weight stays roughly stable. Eat below it and you create a deficit; eat above it and you create a surplus.

The two components that matter most

Your maintenance figure is made up of your basal metabolic rate (BMR) — the calories your body burns simply to keep you alive at rest — plus the extra energy you burn through daily movement, exercise, and activity. Together these are often called your total daily energy expenditure (TDEE).

How the calculation works

The most widely used method applies a formula (such as the Mifflin-St Jeor equation) to your height, weight, age, and sex to estimate BMR, then multiplies by an activity factor — typically ranging from around 1.2 for a largely sedentary day to 1.7 or more for a very active one. The result is a general estimate, not a precise clinical measurement, so treat it as a useful guide rather than a fixed rule.

• Sedentary (little or no exercise): BMR × ~1.2
• Lightly active (light movement most days): BMR × ~1.375
• Moderately active (exercise 3–5 days a week): BMR × ~1.55
• Very active (hard exercise most days): BMR × ~1.725

Why this matters on a GLP-1 medicine

Reduced appetite can mean people eat far below their maintenance level without realising it — which affects energy, muscle retention, and long-term progress. Understanding your maintenance number helps you see how to work out a calorie deficit that is intentional rather than accidental. You can also explore calculating a calorie deficit once you have your maintenance figure in hand.

Keep in mind that maintenance calories are not static. They shift as your weight changes, as your activity level changes, and over time on medication. Revisiting the estimate every few weeks gives you a more accurate picture as your journey progresses.

Knowing your maintenance figure is only useful if you can track against it consistently — and that is where logging your food daily makes the difference.

GLP Trackr's AI photo food scan lets you point your camera at a meal and get an instant calorie and protein breakdown, which is particularly helpful when appetite is low and portions are small but you still want to know where you stand. For packaged foods, the barcode scanner fills in the details in seconds. Both feed directly into your daily calorie total, so you can see at a glance whether you are near your maintenance level, below it, or above it.

Once you have worked out your maintenance calories, you can set a custom calorie target inside the app and track progress toward it each day. The daily check-in also captures weight, energy, and other markers, so you start to see how eating at, above, or below maintenance connects to how you feel and how your weight trends over time — the kind of pattern that is genuinely useful to bring to an appointment with your prescriber or doctor.

For a broader look at energy balance on a GLP-1 medicine, the calorie deficit guide covers the full picture, including how to move from maintenance to a sustainable deficit.

Ready to put your maintenance calories into practice? GLP Trackr makes daily food tracking effortless — snap a photo, scan a barcode, or search, and your numbers update instantly. Start your free 7-day trial on the App Store or Google Play.