How the split is built#
Calories come first: your TDEE (Mifflin-St Jeor BMR × activity) adjusted for the goal — roughly −500 kcal for fat loss, +300 for lean muscle gain. Then the macros are filled in a deliberate order:
- Protein is anchored to bodyweight, not calories: 2.2 g/kg when cutting, 1.8 g/kg otherwise. Muscle does not need less protein just because calories dropped.
- Fat takes about 25% of calories — enough for hormones and food that tastes like food.
- Carbs fill the remainder, fueling training. This is the flexible lever: if you prefer higher fat and lower carb, shifting between them is fine as long as protein and calories hold.
Tracking without obsessing#
Hit protein and calories daily; let fat and carbs land within ±10 g. Weigh yourself a few times a week and judge by the two-week trend — if it is not moving the way you want, adjust calories by 100–200 and hold again.
Prefer to start from the energy side? Get your maintenance number first with the TDEE calculator — it hands its result straight to this page.