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Calorie deficit calculator
How many calories to eat a day to lose weight at your chosen pace, and when you'll reach your target weight.
How the deficit is calculated
First, maintenance is calculated with the Mifflin-St Jeor equation and your activity. Then a deficit for your pace is subtracted: 275, 550 or 825 kcal a day. That's roughly a quarter, a half and three quarters of a kilogram a week.
The math assumes a kilogram of fat holds about 7,700 kcal. In reality weight comes off unevenly: faster in the first weeks because of water, slower after that.
Which pace to choose
Half a kilogram a week suits most people: hunger stays manageable and you keep energy for training. The fast pace makes sense with a lot of weight to lose. The slow pace fits when only a few kilograms are left.
If the deficit is more than a quarter of maintenance, the calculator warns you. A very deep deficit is hard to keep, and you lose muscle along with fat.
The safe minimum
The target never drops below 1,500 kcal for men and 1,200 for women, or below the amount that covers enough protein, fat and carbs. If the number hits the minimum, the time to your goal simply gets longer.
Frequently asked questions
Why isn't my weight moving even in a deficit?
Weight swings by 1 to 2 kg because of water, salt and your cycle. Watch the weekly average. If it doesn't change for two or three weeks, cut 100 to 200 kcal.
Should I recalculate as I lose weight?
Yes, a lighter body burns less. Recalculate every 3 to 5 kg. The Tonus app recalculates your target when you update your weight.
Can I lose weight without working out?
Yes, the deficit will do it. But with strength training you lose more fat and less muscle.
Sources
- Hall K. D. et al. Quantification of the effect of energy imbalance on bodyweight. Lancet, 2011 doi.org/10.1016/S0140-6736(11)60812-X
- Mifflin M. D. et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr, 1990 doi.org/10.1093/ajcn/51.2.241
In the app your calorie target updates by itself when your weight changes
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