How a calorie deficit works
About 7,700 calories equals one kilogram of body fat (≈3,500 per pound). Eating in a consistent daily deficit forces your body to use stored fat for energy. This tool shows three options from your maintenance calories:
- Gentle (−10%) — easiest to sustain, slowest loss.
- Moderate (−20%) — the sweet spot for most people.
- Faster (−25%) — quicker, but harder to maintain and hungrier.
Lose fat without losing muscle
Keep protein high (~2 g/kg), lift weights 2–4 times a week, and don't crash too hard. Very aggressive deficits cost muscle, tank energy, and usually rebound. Aim to lose about 0.5–1% of body weight per week.
When the scale stalls
Weight loss isn't linear — water and hormones mask fat loss. Judge by 2–3 week trends, and recalculate as you get lighter (your maintenance drops as you lose weight).
Limitations
This tool builds on the same Mifflin-St Jeor maintenance estimate as our TDEE calculator, so it carries the same margin of error (roughly ±10%). Treat the numbers as a starting point to adjust from, not an exact prescription.