Macros feel like a puzzle with three unknowns and no rules. There are rules, and they have a clear order: one target is set by physiology, one by a floor you should not cross, and the last one absorbs whatever calories are left.
Step one: protein, set by body weight
Protein is the one macro you should not scale to calories. It is set by body weight because its job — maintaining and building lean tissue — scales with how much tissue you have.
| Situation | Daily protein |
|---|---|
| General health, sedentary | 1.2–1.6 g/kg |
| Cutting, resistance training | 1.6–2.2 g/kg |
| Bulking | 1.6–2.0 g/kg |
| Over 60, or dieting hard | Upper end of the range |
For an 80 kg person cutting, that is 130–175 g. Spread across three or four meals, each containing 0.3–0.4 g/kg, is enough to keep muscle protein synthesis responding. The old “30 g per meal maximum” rule is too strict, but 90 g in one sitting is not better than splitting it.
Step two: fat, as a floor rather than a target
Fat supports hormone production, absorbs fat-soluble vitamins and makes food edible. Below roughly 0.5 g/kg, diets get unpleasant and, in men, testosterone starts to suffer.
- Minimum: 0.5 g/kg
- Comfortable range: 0.6–1.0 g/kg
- Higher intakes are fine if you prefer fattier food and still hit protein
For that same 80 kg person: at least 40 g, more realistically 55–70 g.
Step three: carbohydrate fills the rest
Carbohydrate is the flexible variable. Subtract protein and fat calories from your total and divide by four.
Worked example — 80 kg, cutting, 2,200 kcal per day:
- Protein: 160 g → 640 kcal
- Fat: 70 g → 630 kcal
- Remaining: 930 kcal → 232 g carbohydrate
Same person, bulking at 3,000 kcal: protein 160 g, fat 85 g, carbohydrate becomes roughly 380 g.
That is the whole method. It also explains why low-carb and high-carb diets both work: they move the flexible number, and total calories decide the outcome.
Does carbohydrate timing matter?
Far less than total intake. The hierarchy is:
- Daily calories — decides whether you gain or lose
- Daily protein — decides how much of the change is muscle
- Daily fibre — 25–38 g, decides how the diet feels
- Meal timing — small effect, mostly about performance and appetite
- Specific sources — smallest effect of all
If you train hard, putting a meaningful share of carbohydrate around the session helps performance. If you do not, the timing is noise. Nobody failed a cut because their oats were at 9 p.m.
Fibre is the macro nobody counts
Fibre sits inside the carbohydrate number and does most of the work for satiety, glucose control and gut health. Aim for 25–38 g per day, mostly from whole sources: legumes, oats, berries, vegetables.
A 2,200 kcal diet with 230 g of carbohydrate has room for plenty of refined food. Whether it should be spent that way is a satiety question, not a metabolic one.
A note on alcohol
Alcohol is not a macro in this framework, but it is calories: 7 kcal per gram, and it is prioritised for oxidation over fat. Two beers is roughly 300 kcal, which is most of a 400 kcal deficit. It does not need to be forbidden, but it does need to be counted.
The order matters more than the precision
Hit protein and the fat floor, fill carbohydrate to the calorie target, keep fibre reasonable. Being within 10 g on carbohydrate changes nothing; missing protein by 40 g every day changes quite a lot over four months.
Set the two fixed points properly and the third one takes care of itself.