Caloric Deficit Calculator: Understanding Your Numbers on a GLP-1 Journey

Your caloric deficit is the gap between the calories your body needs to maintain its current weight — often called your Total Daily Energy Expenditure (TDEE) — and the calories you actually consume. When that gap is consistent, your body draws on stored energy, and weight tends to fall over time.

How the calculation works

TDEE is estimated from your Basal Metabolic Rate (BMR) — the calories your body burns at rest — adjusted for your typical activity level. Several validated formulas (such as Mifflin-St Jeor) can estimate BMR from height, weight, age, and biological sex, though any formula gives an estimate rather than a precise measurement. Use the result as a starting point, not a fixed rule.

What deficit size is generally suggested?

A commonly cited guideline in nutritional science is a moderate deficit — often in the range of 300–600 kcal per day — to support steady weight loss while preserving muscle. However, the right target for any individual depends on their health history, activity level, and the guidance of their prescriber or dietitian. GLP Trackr provides educational context; it does not issue personalised calorie prescriptions. Always discuss specific calorie targets with your healthcare professional.

Why this matters on a GLP-1 medicine

Reduced appetite on a GLP-1 medicine can make it surprisingly easy to under-eat — particularly protein — which matters for muscle maintenance. Tracking your actual intake against an estimated target helps you spot whether you are eating enough of the right things, not just less overall. For a deeper look at how a caloric deficit works in practice, see our page on understanding caloric deficit, or explore the related deficit and caloric balance guide. You can also compare approaches with our calorie deficit calculator.

Manually working out a deficit every day is the part most people drop — and that is exactly where GLP Trackr steps in. The most relevant feature here is the app's AI food scanning: point your camera at a meal and get an instant calorie and macro breakdown without typing a thing. On days when appetite is low and meals are small, that frictionless logging makes the difference between having data and having nothing.

Once your food is logged, the app maps it against your personal calorie and protein targets, so you can see your running deficit in real time rather than doing the arithmetic yourself. The daily check-in adds context — weight, energy, and food-noise levels — so you build a picture of how your deficit relates to how you actually feel day to day.

The broader calorie calculator hub brings together all the related tools and guidance if you want to go deeper on your numbers.

GLP Trackr is a tracking and journaling app; the numbers it surfaces are educational starting points. Any decision about your calorie target — especially if you have a medical condition or are on other medicines — should be made with your prescriber or a qualified dietitian, not on your own.

Ready to stop guessing and start seeing your deficit clearly? Download GLP Trackr free on the App Store or Google Play and explore it with a 7-day free trial — no commitment needed.