• Under 18.5 — Underweight
• 18.5–24.9  — Healthy weight
• 25.0–29.9  — Overweight
• 30.0+      — Obese (Class I–III)

BMI doesn't account for muscle mass, bone density, or fat distribution — use it as one data point, not a diagnosis.

• BMR — calories burned at complete rest
• TDEE — total daily energy expenditure
• Deficit of ~500 cal/day ≈ ~1 lb/week loss
• Surplus of ~250–500 cal/day for muscle gain

Calculated using the Mifflin-St Jeor equation — the most validated BMR formula for general populations.