Mifflin-St Jeor equation — Men: 10W + 6.25H − 5A + 5; Women: 10W + 6.25H − 5A − 161
30-year-old man, 75 kg, 178 cm: BMR = 10(75) + 6.25(178) − 5(30) + 5 = 1,738 kcal/day.
Basal Metabolic Rate: calories burned at complete rest to maintain basic bodily functions.
TDEE multiplies BMR by an activity factor to estimate total daily calorie needs.