Calorie Deficit Calculator: The Science of Sustainable Fat Loss
You Cannot Outrun a Bad Diet
Weight loss requires consuming fewer calories than you burn. This calorie deficit is the ONLY mechanism for fat loss — no specific food, supplement, or exercise routine bypasses it. The question is: how large should your deficit be, and how do you create one sustainably?
Step 1: Find Your TDEE
Your TDEE (Total Daily Energy Expenditure) is how many calories you burn daily. Calculate it using the TDEE calculator. For most Indian adults, TDEE is between 1,800–2,800 calories depending on weight, height, age, and activity level.
Step 2: Set Your Deficit
| Deficit Size | Weekly Fat Loss | Who It’s For |
|---|---|---|
| 250 cal/day (small) | ~0.25 kg | Already lean, want to minimise muscle loss |
| 500 cal/day (moderate) | ~0.5 kg | Most people — sustainable and effective |
| 750–1000 cal/day (aggressive) | 0.75–1 kg | Significantly overweight, short-term only |
Why Crash Diets Backfire
- Metabolic adaptation: Large deficits (>1000 cal) cause your metabolism to slow down, making continued loss harder
- Muscle loss: Without adequate protein and resistance training, up to 25% of weight lost can be muscle
- Hormonal disruption: Extreme restriction affects thyroid, leptin, and cortisol
- Rebound: 95% of crash dieters regain the weight within 1–2 years
The formula: Target intake = TDEE – 500. Maintain high protein (1.6–2.2g/kg), lift weights 3–4x/week, and aim for 0.5 kg/week loss. Patience beats speed every time.