Calorie Calculator: The Science of Weight Loss and Muscle Gain
Calorie calculation forms the mathematical foundation of body composition management. Understanding your energy requirements eliminates guesswork and accelerates results.
Energy Balance
- Deficit of 500 cal/day: ~1 lb fat loss per week
- Surplus of 300 cal/day: ~0.6 lb lean mass gain per week
- Maintenance: Weight stability at current body composition
BMR vs. TDEE
Basal Metabolic Rate (BMR) represents calories burned at complete rest. Total Daily Energy Expenditure (TDEE) includes BMR plus all physical activity.
Mifflin-St Jeor Equation:
Men: BMR = 88.362 + (13.397 × weight kg) + (4.799 × height cm) - (5.677 × age)
Women: BMR = 447.593 + (9.247 × weight kg) + (3.098 × height cm) - (4.330 × age)
Men: BMR = 88.362 + (13.397 × weight kg) + (4.799 × height cm) - (5.677 × age)
Women: BMR = 447.593 + (9.247 × weight kg) + (3.098 × height cm) - (4.330 × age)
Macronutrient Distribution
- Protein (4 cal/g): 1.6-2.2g per kg for active individuals
- Carbohydrates (4 cal/g): Primary fuel for high-intensity exercise
- Fats (9 cal/g): Critical for hormone production
Medical Disclaimer: Consult a registered dietitian or physician before making major dietary changes.