TDEE & Macro Target Calculations

BMR (Basal Metabolic Rate)

Formula: Mifflin-St Jeor (1990)

Male:    BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Female:  BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Why this formula? Systematic reviews (Frankenfield et al. 2005) have shown Mifflin-St Jeor is the most accurate equation for predicting RMR in healthy, non-obese adults — preferred over the older Harris-Benedict equation.

Accuracy: ±10% of measured values for ~80% of people. Individual metabolic variation means this is an estimate, not a prescription — adjust based on real-world results over 2-3 weeks.

TDEE (Total Daily Energy Expenditure)

Formula: BMR × activity multiplier

Activity Level	Multiplier	Description
Sedentary	1.2	Desk job, little or no exercise
Lightly Active	1.375	Light exercise 1-3 days/week
Moderately Active	1.55	Moderate exercise 3-5 days/week
Very Active	1.725	Hard exercise 6-7 days/week
Extremely Active	1.9	Hard daily exercise + physical job

Choose conservatively. Most people overestimate activity. When in doubt, pick one level lower — you can always adjust upward if you're losing weight too fast.

Goal Calorie Adjustments

Goal	Adjustment	Result
Cut	−500 kcal	~0.5 kg fat loss/week
Maintain	0 kcal	Recomposition (slow)
Bulk	+300 kcal	~0.25 kg lean gain/week

Why modest adjustments?

• Cut: A 500 kcal deficit = 3500 kcal/week = ~1 lb of fat. Larger deficits risk muscle loss, energy crashes, rebound.
• Bulk: A 300 kcal surplus maximizes lean-to-fat gain ratio. Larger surpluses add more fat than muscle (diminishing returns).
• Recomposition (maintain): Possible for beginners, returners, or those with body fat to lose. Slower progress but sustainable.

Macro Distribution

The app uses this priority order:

1. Protein (fixed): 1.8 g/kg body weight — see protein research
2. Fat (fixed): 0.8 g/kg body weight — minimum for hormonal health
3. Carbs (remainder): Fill remaining calories

Example (70 kg person, bulk goal, moderate activity):

• BMR: 1650 kcal
• TDEE: 2558 kcal
• Calorie target: 2858 kcal (+300 surplus)
• Protein: 126 g × 4 = 504 kcal
• Fat: 56 g × 9 = 504 kcal
• Carbs: (2858 - 504 - 504) / 4 = 463 g

Why Fat Minimum 0.8 g/kg?

Dietary fat is essential for:

• Hormone production (testosterone, estrogen, cortisol)
• Fat-soluble vitamin absorption (A, D, E, K)
• Cell membrane integrity

Below ~20% of calories from fat (roughly 0.6 g/kg at maintenance), hormonal health begins to decline. The app uses 0.8 g/kg as a safer minimum.

Calorie Balance Zones

The Nutrition page color-codes daily calorie intake vs TDEE:

• 🔴 Deficit: Intake < TDEE (fat loss territory)
• ⚪ Maintenance: Intake ≈ TDEE (±100 kcal)
• 🟢 Surplus: Intake > TDEE (muscle gain territory)

Limitations & Adjustments

The calculator is a starting point, not a prescription.

Adjust after 2-3 weeks if:

• Losing >1 kg/week on cut → eat more
• Losing nothing on cut → eat less or increase activity
• Gaining >0.4 kg/week on bulk → eat less
• Gaining nothing on bulk → eat more

Body composition changes matter more than scale weight. Track measurements (waist, hip, arm) and progress photos alongside weight.

Override Any Target

The app lets you manually override any calculated target. Use this if:

• Your dietitian/coach gave you specific numbers
• Empirical results differ from the calculator
• You're following a specific protocol (keto, IF, etc.)