TDEE stands for total daily energy expenditure: the number of calories a person burns in a day, including everything from keeping their heart beating to the walk to the car and the session with you. It is the number a meal plan is built around. Eat about that much and weight holds; eat less and it falls; eat more and it rises. This is how to estimate it, and what to do with it.
The pieces
BMR, basal metabolic rate, is the energy the body uses at complete rest: breathing, circulation, keeping warm, repairing tissue. For most people it is the biggest part of the day's burn.
Activity is everything else: training, walking, standing, fidgeting, and the work of digesting food. Rather than measure it, the standard approach multiplies BMR by a factor that reflects how active the person is.
TDEE is BMR multiplied by the activity factor.
Estimating BMR
Two formulas are in common use.
Mifflin-St Jeor uses weight, height, age and sex. It is the default when body composition is unknown, and the one most calculators use.
- Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Katch-McArdle uses lean body mass instead, so it needs a body-fat percentage. When that figure is reliable it is the better choice for lean or muscular clients, because it does not treat muscle and fat the same.
- Lean mass (kg) = weight × (1 − body fat ÷ 100)
- BMR = 370 + 21.6 × lean mass
Both are estimates. A real person's BMR can sit 10% either side of the formula, which is why the number you get is a starting point to adjust against what the scale does over a few weeks.
Activity multipliers
| Level | Description | Multiply BMR by |
|---|---|---|
| Sedentary | Desk job, little exercise | 1.2 |
| Lightly active | Exercise 1 to 3 days a week | 1.375 |
| Moderately active | Exercise 3 to 5 days a week | 1.55 |
| Very active | Hard exercise 6 to 7 days a week | 1.725 |
| Extremely active | Physical job plus training | 1.9 |
Most people overestimate their level. A client who trains three times a week and sits at a desk the rest of the time is lightly to moderately active, not very active. When in doubt, pick the lower level and adjust up if weight falls faster than expected.
A worked example
A 34-year-old woman, 165 cm, 68 kg, training three times a week with a desk job.
- BMR (Mifflin-St Jeor): 10 × 68 + 6.25 × 165 − 5 × 34 − 161 = 680 + 1,031 − 170 − 161 = 1,380 kcal
- TDEE at lightly active: 1,380 × 1.375 = about 1,900 kcal
That is her maintenance figure. To lose fat at a sensible rate, a deficit of 15 to 20% is the usual range: about 1,520 to 1,615 kcal. To build muscle, a surplus of around 10%: about 2,090 kcal.
Turning calories into macros
Calories set the direction; the macro split affects how it feels and what is kept. A common coaching default:
- Protein at 1.6 to 2.2 grams per kilogram of bodyweight, higher in a deficit to protect muscle. For the client above at 2 g/kg, that is 136 g, or 544 kcal.
- Fat at about 25% of calories. At 1,550 kcal, that is about 43 g.
- Carbohydrate fills the rest: 1,550 − 544 − 387 = about 619 kcal, or 155 g.
None of this is sacred. A client who trains hard in the evening may do better with more carbohydrate; one who finds fat satiating may prefer 30%. Hit the protein, keep the calories, and adjust the rest to the person.
Adjusting from there
The formula gives a starting point. The scale, measurements and how the client reports feeling over two to three weeks give the answer. If weight holds on the "deficit" number, the estimate was high: take 100 to 150 kcal off and watch again. If it drops faster than about 0.5 to 1% of bodyweight a week, add some back. Recalculate when weight changes by more than a few kilograms, because BMR moves with it.
The free macro calculator does the arithmetic above. Inside TrainerStack the same calculator sits on each client's nutrition tab, uses Katch-McArdle automatically when a body-fat figure is recorded, and feeds the targets straight into their meal plan, where each meal is fitted to the numbers by the gram.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is the energy the body uses at complete rest. TDEE is BMR plus everything else the person does in a day, estimated by multiplying BMR by an activity factor. Meal plans are built around TDEE, not BMR.
Which formula is most accurate?
For most people Mifflin-St Jeor is the best choice when body fat is unknown. Katch-McArdle is more accurate for lean or muscular people when a reliable body-fat percentage is available. Both are estimates to be adjusted against real results.
How big should a calorie deficit be?
A deficit of 15 to 20% below TDEE is a common range for fat loss that can be sustained. Larger deficits lose weight faster but cost muscle, energy and adherence. Very low calorie targets should not be set without medical input.
How much protein should a client eat?
A commonly cited range is 1.6 to 2.2 grams per kilogram of bodyweight per day, with the higher end useful in a deficit or for people trying to gain muscle.
How often should I recalculate TDEE?
When bodyweight has changed by more than a few kilograms, when activity changes substantially, or when results stall for two to three weeks at a target that was working.