How this calorie deficit calculator works
A calorie deficit means eating fewer calories than your body burns, so it makes up the gap from stored fat. The calculator does it in two steps:
- Maintenance calories. Your basal metabolic rate (BMR, the energy you burn at rest) from the revised Harris-Benedict equation, multiplied by an activity factor from 1.2 (sedentary) to 1.725 (very active).
- Daily targets. Maintenance minus 250, 500 or 750 kcal for a relaxed, steady or aggressive pace. Targets never go below 1,200 kcal for women or 1,500 kcal for men.
These are the same equations, deficits and floors the Calo AI app uses to set your daily target, so the numbers here match what you would see in the app.
How fast will I lose weight in a calorie deficit?
The rule of thumb is that about 7,700 kcal equals 1 kg of body fat. A 500 kcal daily deficit adds up to 3,500 kcal a week, or roughly 0.45 kg. The table below shows the three paces:
| Pace | Daily deficit | Weekly loss (approx.) | Good for |
|---|---|---|---|
| Relaxed | 250 kcal | 0.23 kg | The last few kilos, or a busy period |
| Steady | 500 kcal | 0.45 kg | Most people, most of the time |
| Aggressive | 750 kcal | 0.68 kg | Larger bodies with more to lose, short stretches |
Real weight loss slows over time. As you get lighter you burn a little less, so the same intake makes a smaller deficit. Research from the US National Institutes of Health shows the 7,700 kcal rule overestimates long-term loss for exactly this reason. Recalculate every 4 to 5 kg.
Worked example
A 30 year old woman, 160 cm and 70 kg, who exercises 1 to 3 days a week:
- BMR (revised Harris-Benedict) = 447.6 + 9.247 x 70 + 3.098 x 160 - 4.33 x 30 = about 1,461 kcal
- Maintenance = 1,461 x 1.375 = about 2,008 kcal
- Steady target = 2,008 - 500 = about 1,508 kcal a day, for roughly 0.45 kg a week
Tips for sticking to a deficit with Indian food
- Measure the oil, not just the food. One tablespoon of oil or ghee is about 120 kcal, and a home tadka often uses two or three.
- Count rotis and katoris. A medium roti is about 40 g of dough. Our roti calories page shows how size and ghee change it.
- Lead with protein. Dal, paneer, curd, eggs and chicken keep you full for longer on fewer calories. See the protein calculator.
- Track for two weeks honestly before deciding a target does not work. Snapping a photo of each plate in an app makes this far quicker than weighing.