Calorie Deficit
Weight loss target calories
About This Calculator
A calorie deficit occurs when you consume fewer calories than you burn, causing the body to use stored energy (fat and sometimes muscle) for fuel. One pound of fat stores approximately 3,500 calories, so a daily deficit of 500 calories theoretically produces 1 lb/week of fat loss. In practice, metabolic adaptation means actual results may differ.
Formula
Deficit = TDEE − Calories Consumed
Weekly fat loss (lbs) ≈ Weekly deficit / 3,500
Weekly fat loss (kg) ≈ Weekly deficit / 7,700
Safe deficit: 300-700 kcal/day for 0.3-0.7 kg/week
Example Calculation
TDEE = 2,500 kcal; eat 2,000 kcal/day
- Daily deficit = 2,500 − 2,000 = 500 kcal
- Weekly deficit = 500 × 7 = 3,500 kcal
- Expected fat loss = 3,500 / 3,500 = 1 lb/week (≈ 0.45 kg)
Expected weight loss: ~1 lb (0.45 kg) per week
Calorie Deficit and Expected Weight Loss
| Daily Deficit | Weekly Loss (lbs) | Weekly Loss (kg) | Monthly Loss (kg) |
|---|---|---|---|
| 250 kcal | 0.5 lb | 0.23 kg | ~1 kg |
| 500 kcal | 1 lb | 0.45 kg | ~2 kg |
| 750 kcal | 1.5 lbs | 0.68 kg | ~3 kg |
| 1,000 kcal | 2 lbs | 0.91 kg | ~4 kg |
Frequently Asked Questions
Is the '3,500 calories per pound' rule accurate?
It's a useful approximation but not exact. Weight loss includes water, glycogen, and some muscle alongside fat, especially early on. Metabolic adaptation also means the rate slows over time. Expect 0.7-0.9 kg/week at a 500 kcal/day deficit rather than the theoretical 1 lb.
How large should my calorie deficit be?
A moderate deficit of 300-700 kcal/day (producing 0.3-0.7 kg/week loss) is recommended for sustainable fat loss with minimal muscle loss. Very large deficits (1,000+ kcal/day) cause faster weight loss but risk muscle catabolism, nutrient deficiencies, and metabolic slowdown.
Why do I stop losing weight even in a deficit?
Weight loss plateaus occur because: (1) metabolic adaptation reduces TDEE as you lose weight, (2) you weigh less so burn fewer calories moving, (3) water retention can mask fat loss temporarily. Reassess your TDEE based on your new weight and adjust calories.
Does the type of food matter, not just calories?
Calories are primary for weight change, but food quality affects body composition and health. High protein intake (1.6-2.2g/kg) preserves muscle during deficit. Whole foods improve satiety. Highly processed foods cause hunger spikes. 'Calories in, calories out' is correct but oversimplified.