The Best Macro Split for Cutting (And Why the Split Matters Less Than You Think)
Set protein high, fat to a floor, and carbs with whatever's left. Here's how to calculate a cutting split, with worked numbers.
For fat loss, set protein at 2.0–2.4 g per kg of bodyweight, fat at a floor of 0.6–0.8 g per kg, and fill the remaining calories with carbohydrate. In percentage terms that usually lands somewhere around 35–40% protein, 25–30% fat, 30–40% carbs — but percentages are the output, not the input. Two people at the same “40/30/30” can have wildly different protein in grams, and grams are what your body responds to.
Set the deficit first
The split does nothing without an energy deficit. Sequence matters:
- Estimate maintenance calories. Bodyweight in kg × 30–33 for moderately active people (in pounds: × 14–15). Or take the average of two weeks of honest logging at stable weight, which is more accurate than any formula.
- Subtract 15–25%. That’s a rate of roughly 0.5–1.0% of bodyweight lost per week. Faster deficits cost you more muscle and more adherence for very little extra fat loss.
- Then split the remaining calories using the priority order below.
The priority order
Protein first — 2.0–2.4 g/kg. In a deficit, the body will take amino acids from somewhere. High protein plus resistance training is what makes that somewhere not your muscle. It’s also the most satiating macro per calorie, which makes the deficit tolerable. See how much protein per day for where those numbers come from.
Fat second — a floor, not a target: 0.6–0.8 g/kg. Fat matters for hormone production and fat-soluble vitamin absorption, and dropping very low for extended periods is where people report the classic run-down cutting symptoms. Set the floor and don’t go under it. There’s no benefit to going far above it either, since fat is the least satiating macro per calorie for most people.
Carbs last — whatever calories remain. Carbohydrate is the training fuel. Whatever is left after protein and fat should go here, because it’s what keeps your lifts from collapsing while you’re eating less. If your remaining carb number comes out very low, your deficit is too aggressive — raise calories rather than cutting fat below the floor.
Worked example
An 80 kg person, maintenance ≈ 2,600 kcal, cutting at a 20% deficit:
| Step | Calculation | Result |
|---|---|---|
| Target calories | 2,600 × 0.80 | 2,080 kcal |
| Protein | 80 kg × 2.2 g | 176 g → 704 kcal |
| Fat | 80 kg × 0.7 g | 56 g → 504 kcal |
| Remaining for carbs | 2,080 − 704 − 504 = 872 kcal | 218 g |
| Resulting split | — | 34% P / 24% F / 42% C |
Note that this “best” cutting split is 42% carbohydrate — nowhere near the low-carb prescriptions that dominate cutting advice. That falls out of the arithmetic, not from a preference.
Common splits compared
| Split (P/C/F) | Who it suits | Trade-off |
|---|---|---|
| 40/40/20 | Lifters cutting with high training volume | Very low fat can be hard to sustain past 8–10 weeks |
| 35/35/30 | Most people, most of the time | The reasonable default |
| 40/20/40 (low-carb) | People who prefer it, or who find carbs trigger overeating | Training performance often drops; no metabolic advantage at matched protein and calories |
| 30/50/20 | Endurance athletes cutting | Protein may be too low to fully protect lean mass |
Direct comparisons of low-carb against higher-carb diets, when calories and protein are matched, consistently show no meaningful difference in fat loss. The split you’ll actually adhere to beats the split that’s theoretically 2% better.
What to change when the scale stalls
A stall of under two weeks is usually water, not fat — especially around a change in training, sodium, or the menstrual cycle. If it persists past two to three weeks:
- Check your logging honestly. Under-reporting is the most common cause by a wide margin — untracked oils, drinks, and bites. Weigh food for a week before concluding your metabolism is the problem.
- Reduce calories by 5–10%, taken from carbs and fat, never protein.
- Add activity instead of cutting further if you’re already at a steep deficit. Daily step count is the most sustainable lever.
- Consider a maintenance break. One to two weeks at maintenance after a long cut restores training quality and adherence, and costs less total time than grinding through a stall.
Frequently asked questions
What is the best macro split for fat loss? Protein 2.0–2.4 g/kg, fat 0.6–0.8 g/kg, carbs with the remaining calories, inside a 15–25% deficit. Expressed as percentages that’s typically about 35/30/35 P/F/C, but the grams are what to set.
Should I cut carbs or fat? Fat, down to the 0.6–0.8 g/kg floor — then carbs. Cutting carbs first tends to hurt training performance, which is what preserves muscle in the first place.
How fast should I lose weight when cutting? 0.5–1.0% of bodyweight per week. Faster costs disproportionately more lean mass and adherence.
Do I need to hit my macros exactly? No. Within about 5–10 g of each target is a normal successful day, and the weekly average matters more than any single day.
Does meal timing matter for cutting? Very little compared with the daily totals. Spreading protein across 3–5 meals is a mild optimisation; when you eat your carbs is largely preference and training schedule.
Not sure whether to track macros at all? Start with macros vs calories.