How Many Calories Does It Take to Lose a Pound?

The 3,500-calorie-per-pound estimate has been used in nutrition guidance for decades. It is based on the approximate energy stored in one pound (roughly 0.45 kg) of human body fat. In simple terms, if you consistently eat fewer calories than your body burns — or burn more through activity — that cumulative shortfall is what drives fat loss over time.

Turning that into a weekly target

Dividing 3,500 by seven gives a daily deficit of about 500 calories to lose approximately one pound a week. A smaller deficit of around 250 calories a day would point toward roughly half a pound a week. These are useful starting reference points, but they are general estimates — individual results vary based on metabolism, body composition, activity level, and other factors. No calculator can account for every variable, and specific targets for you should be discussed with your prescriber or doctor.

Why GLP-1 users often see this play out differently

Many people taking Mounjaro (tirzepatide) or Wegovy (semaglutide) report a noticeable reduction in appetite and "food noise" — the constant background preoccupation with food that can make calorie management difficult. This means the calorie deficit many users experience is less about rigid restriction and more about a natural shift in how much they want to eat. Tracking your actual intake gives you a clearer view of what is really happening. For more on setting a daily intake goal, see how many calories to eat to lose weight on a GLP-1 and our deeper look at the calories-per-pound calculation explained.

Important caveats

• The 3,500-calorie rule is a population-level estimate, not a precise personal formula.
• Weight loss is rarely perfectly linear — water retention, hormonal shifts, and muscle changes all affect the scale week to week.
• Very low calorie intakes can lead to muscle loss and nutritional gaps; any significant dietary change is worth discussing with your healthcare professional.
• Progress tracking over several weeks gives a much more reliable picture than any single day or week.

For a quick reference on the numbers involved, our page on calories to a pound — the key figures breaks down the maths clearly.

Manually calculating a running calorie deficit every day is where most tracking efforts break down — especially when appetite is low and meals are smaller or less predictable. GLP Trackr's AI food scanning takes the friction out of it: point your camera at a meal and get an instant calorie and protein breakdown, without needing to search a database or weigh everything.

Once you have set a daily calorie target in the app, every meal you log — whether by photo scan, barcode, or manual search — feeds directly into your daily total. The app shows your remaining calories at a glance, so you can see your deficit building across the day without any mental arithmetic. Combined with the daily check-in (which captures weight each morning), you get a week-by-week view of how your intake and progress are actually relating to each other.

If you want to explore the broader framework for setting your targets, the GLP Trackr calorie calculator hub brings together the key tools and guidance in one place.

GLP Trackr is built for people already on Mounjaro or Wegovy — it does not prescribe targets or replace your prescriber's guidance. Any decision about your calorie goals is best made in conversation with your healthcare professional, who knows your full picture. The app helps you collect the data that makes those conversations more informed.

Ready to stop estimating and start seeing your real numbers? Download GLP Trackr on the App Store or Google Play and try it free for seven days — your first week of tracking is on us.