Quick Answer
What is TDEE? Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a day, including everything from breathing and digestion to exercise and daily movement.
The formula: TDEE = BMR × PAL, where BMR is your Basal Metabolic Rate and PAL is your Physical Activity Level (activity multiplier).
Simple example: a 45-year-old female, 165 cm, 60 kg, moderate exercise (PAL 1.55).
BMR = (10 × 60) + (6.25 × 165) − (5 × 45) − 161 = 600 + 1,031.25 − 225 − 161 = 1,245.3 kcal/day.
TDEE = 1,245.3 × 1.55 = 1,930.1 kcal/day.
What this means: to maintain weight, eat about 1,930 kcal/day; to lose weight, eat 300–500 kcal less; to gain weight, eat 300–500 kcal more.