Before you argue about keto vs high-carb, get the one number that decides fat loss or gain: your daily calories. Everything else is a detail on top of it.
Step 1, your BMR (Mifflin–St Jeor)
Basal metabolic rate is what you'd burn lying in bed all day. The Mifflin–St Jeor formula is the most accurate common one:
- Men: 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
- Women: 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Step 2, multiply by activity
| Activity | Multiplier |
|---|---|
| Sedentary (desk, little exercise) | 1.2 |
| Light (1–3 sessions/week) | 1.375 |
| Moderate (3–5 sessions/week) | 1.55 |
| Very active (6–7 sessions/week) | 1.725 |
BMR × multiplier = your maintenance calories (TDEE), the number that keeps your weight stable.
Step 3, set your target
- Fat loss: subtract 15–20% (about 300–500 kcal). Aim to lose ~0.5–1% of bodyweight per week.
- Muscle gain: add 5–10% (about 150–300 kcal). Slower is leaner.
- Recomp / maintenance: eat at maintenance and let training drive the change.
Step 4, adjust with the scale, not the formula
The formula is a starting estimate, not gospel. Track your weight every morning, take the weekly average, and if it isn't moving the way you want after two weeks, nudge calories by ~150 and re-check. Your real intake and your trend beat any calculator.
Protein comes first
Whatever your calorie target, hit roughly 1.6–2.2 g of protein per kg of bodyweight. It protects muscle in a cut and builds it in a bulk, and it's the most filling macro, which makes the calorie target easier to hit.