Every diet starts with one question: how many calories? And in most practices the answer comes from an external calculator, a spreadsheet or mental math, and then gets typed into the diet by hand.
Now the BMR and TDEE calculation lives inside diet planning, with the client’s data already filled in.
BMR and TDEE in 30 seconds
- BMR (basal metabolic rate): the energy burned at complete rest, just to keep the body running.
- TDEE (total daily energy expenditure): BMR multiplied by the activity factor — how much the person burns on a normal day.
The most common activity factors:
| Level | Factor |
|---|---|
| Sedentary | 1.2 |
| Lightly active | 1.375 |
| Moderately active | 1.55 |
| Very active | 1.725 |
| Extremely active | 1.9 |
Which formula to choose
- Mifflin-St Jeor: the current reference for the general population. Uses weight, height, age and sex.
- Harris-Benedict (revised, 1984): the classic, and the same one used in Fitney’s fitness assessments. That way the BMR in the diet matches the one in the assessment.
- Katch-McArdle: uses lean mass. It’s the best option when you have body fat percentage from a recent assessment, especially for athletes and people with above- or below-average body composition.
How it works in diet planning
- While building the client’s diet, open the energy calculation.
- Weight, height, age and sex come from the profile, and body fat percentage comes from the latest assessment.
- Choose the formula and the activity factor, and TDEE appears instantly.
- If you want, enter a kcal adjustment (for example, −400 for a deficit) and tap apply as target. The diet’s calorie target is filled in and the macros start from it.
- The calculation is saved with the diet: at the next review, you can see which formula and factor were used.
From maintenance to target
TDEE is maintenance. From there you apply your approach:
- weight loss: a moderate calorie deficit;
- muscle gain: a controlled surplus;
- recomposition: close to maintenance, with high protein.
Then macros are calculated automatically as you build the meals. See the step by step in how to build a meal plan.
Conclusion
With the client’s data already filled in and the calculation saved in the diet, the calorie target no longer depends on an external tool, and every review is traceable.
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