Calorie Deficit Calculator
Calculate evidence-based caloric deficits for safe, sustainable fat loss
Deficit of 545 kcal/day below maintenance (2726 kcal)
Mathematical Formula & Scientific Methodology
Formula: Proportional Calorie Deficit
Intake = TDEE × (1 - DeficitFraction)Applies a proportional reduction rather than arbitrary flat subtractions (like 500 kcal for everyone) to preserve lean mass.
Model Assumptions
- Sufficient dietary protein to prevent muscle wasting
Variables & Standard Units
| Symbol | Physiological Meaning | Unit |
|---|---|---|
| TDEE | Total energy expenditure | kcal |
| DeficitFraction | Percentage reduction (e.g. 0.20 for 20%) | dimensionless |
Scientific Limitations
- Deficits exceeding 25% often trigger excessive hunger hormones (ghrelin) and NEAT decline
Peer-Reviewed Scientific Citations
A new predictive equation for resting energy expenditure in healthy individuals (1990)
Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO (1990) — The American Journal of Clinical Nutrition, 51(2), 241-247
Key Finding: Mifflin-St Jeor equation is accurate within ±10% of measured REE in non-obese and obese individuals, recommended by the Academy of Nutrition and Dietetics as the most reliable standard equation.
Frequently Asked Questions
Related Calculators & Next Steps
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