Protein & macro split

Protein is the only macro with a job nothing else can cover. It supplies the amino acids your body uses to repair the muscle you damaged in training, and to hold onto tissue while you are eating less than you burn. That is why the calculator fixes it before anything else — it is a floor, not a slice of the pie. Most people training regularly land between 1.6 and 2.2 grams per kilogram of bodyweight, and the upper half of that band earns its keep during a cut. Spread it across three or four meals rather than stacking it at dinner. Roughly 0.4 g per kilogram per sitting is the point where the repair signal reliably fires.

Breaks when all of it arrives at dinner.

Fat is set second because it also has a floor, just a quieter one. Below roughly 0.5 grams per kilogram of bodyweight most people start to notice: sex hormone production suffers, the fat-soluble vitamins A, D, E and K travel less well, and meals stop feeling like meals. Very low fat diets tend to fail on adherence long before they fail on physiology. Above that floor the exact figure is preference rather than prescription. Some people run well with fat high and carbohydrate modest; others feel flat within a week of the same arrangement.

Breaks when cut to flatter the carb number.

Carbohydrate gets the remainder, and that is a promotion rather than an insult. It is the fuel your body reaches for first at the intensities that make training hard, and the one that refills muscle glycogen between sessions. The right amount is set by the week in front of you, not by a rule — someone lifting five times and running twice needs meaningfully more than someone walking and lifting twice. If your last sets feel heavier than your first and your sleep is fine, the remainder is probably too thin.

Breaks when the training week changes and the number does not.