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Mifflin-St Jeor · BMR & TDEE · Macro Grams (Protein, Carbs, Fats)

Calorie Deficit Calculator

Calculate your exact daily caloric maintenance, optimal fat-loss deficit tiers, and customized macronutrient grams.

Units:
Presets:
lbs
≈ 81.6 kg
ft
in
≈ 178 cm
Includes work routines & workouts
Target Daily Calories
2263 kcal
Moderate Deficit (-1.0 lb / -0.5 kg per week)
Maintenance TDEE
2763 kcal
Total Daily Energy Expenditure
Basal Metabolic Rate (BMR)
1783 kcal
Calories burned resting in bed 24h

Daily Macronutrient Targets

Macronutrient gram amounts tailored to 2263 kcal
Protein (4 kcal/g)
226g
905 kcal (40% of diet)
Carbohydrates (4 kcal/g)
198g
792 kcal (35% of diet)
Fats (9 kcal/g)
63g
566 kcal (25% of diet)

Metabolic Science: BMR, TDEE & The Energy Balance Equation

The Mifflin-St Jeor Equation

Published in 1990 in The American Journal of Clinical Nutrition, systematic reviews by the Academy of Nutrition and Dietetics deem it the most accurate predictive resting metabolic rate formula:

Men: 10W + 6.25H - 5A + 5
Women: 10W + 6.25H - 5A - 161

Where W is weight in kilograms, H is height in centimeters, and A is age in years.

Sustainable Deficits vs. Crash Starvation

One pound of adipose body fat stores roughly 3,500 kilocalories of metabolic energy.

A daily 500 kcal deficit produces approximately 1 pound of fat loss per week (500 × 7 = 3,500 kcal).

Deficits exceeding 25% of TDEE risk elevated cortisol, metabolic adaptation, and lean muscle catabolism.

Macronutrient Energy Densities

Every gram of food contains specific caloric energy:

  • Protein: 4 kcal/gram (highest thermic effect of food: 20–30%)
  • Carbohydrates: 4 kcal/gram (glycogen replenishment & brain fuel)
  • Fats: 9 kcal/gram (essential hormone and cellular membrane production)