Calorie Deficit Calculator

While the old rule of "3,500 calories equals one pound of fat" is commonly cited, modern research shows that weight loss is more complex. Your body adapts to calorie restriction in several ways:

• Metabolic Adaptation: Your metabolism slows by 5-15% as you lose weight, making further weight loss more difficult
• Body Composition Changes: You lose both fat and some lean mass, affecting your calorie needs
• Hormonal Adjustments: Hunger hormones (ghrelin and leptin) change, affecting appetite and energy levels
• Non-Linear Progress: Weight loss isn't constant; you'll experience plateaus and fluctuations

This calculator accounts for metabolic adaptation to provide more realistic estimates than simple calorie math.

The best deficit level depends on several factors:

Healthcare professionals generally recommend minimum calorie intakes to ensure adequate nutrition:

• Women: Generally should not go below 1,200 calories per day
• Men: Generally should not go below 1,500 calories per day

Going below these thresholds makes it difficult to get adequate vitamins, minerals, and protein. Very low-calorie diets should only be undertaken under medical supervision.

You may notice that your weight loss projections show a slowdown over time. This is normal and expected due to:

• Lower body weight: Smaller bodies burn fewer calories, so your TDEE decreases as you lose weight
• Metabolic adaptation: Your body becomes more efficient, burning 5-15% fewer calories than expected for your new weight
• Reduced activity thermogenesis: You may unconsciously move less throughout the day

To continue losing weight, you'll need to either reduce calories further or increase physical activity. Most experts recommend recalculating your targets every 5-10 kg (10-20 lbs) of weight loss.

Maximize your success with these evidence-based strategies:

Recalculate your calorie targets when:

• You've lost 5-10 kg (10-20 lbs) from your starting weight
• Your weight hasn't changed for 3-4 weeks despite consistent tracking
• Your activity level changes significantly
• You experience excessive hunger, fatigue, or other negative symptoms

Remember: The calculator provides estimates based on averages. Individual results vary due to factors like genetics, medication, sleep, stress, and adherence. Use the projections as guidelines, but listen to your body and adjust as needed.