Cutting Macros: How to Set Protein, Carbs and Fat for Fat Loss

In this guide

1. What "cutting macros" actually means

2. Why protein goes up, not down, during a cut

3. Carbs vs. fat — which should you cut harder?

4. How big should your cutting deficit be?

5. A worked cutting macro example

6. A 7-day cutting macro framework

7. Adjusting your macros as the cut progresses

8. Frequently asked questions

If you've already read our guide on lean bulking macros, this is the other side of the same coin — the macro strategy for the phase where the goal flips from building muscle to revealing it. Cutting is where most people's macro approach falls apart, usually because they apply bulking-era thinking (or worse, crash-diet thinking) to a phase that needs its own specific rules.

Effective cutting macros keep protein high (1.8–2.4g/kg body weight — higher than maintenance or bulking targets) to protect muscle in a deficit, set fat at a floor of roughly 20% of calories for hormonal health, and let carbohydrates absorb most of the calorie reduction. The deficit itself should be moderate — 15–25% below TDEE — since more aggressive cuts accelerate muscle loss without meaningfully speeding fat loss.

Use the calorie deficit calculator to find your exact starting numbers before applying the macro splits below.

What "Cutting Macros" Actually Means

A cut is a deliberate calorie deficit phase, typically following a period of muscle-building (a bulk) or simply undertaken to reduce body fat while preserving as much existing muscle as possible. The macro strategy during a cut differs from maintenance or bulking in one crucial way: protein's relative priority increases significantly, because it's the single most protective factor against muscle loss when total calories are reduced.

Why Protein Goes Up, Not Down, During a Cut

This surprises people used to thinking of "dieting" as simply eating less of everything. In a calorie deficit, the body is more prone to breaking down muscle tissue for energy — a risk that rises the larger the deficit and the leaner you already are. Higher protein intake directly counters this by preserving muscle protein synthesis signals even while overall energy intake is reduced.

Phase	Protein Target	Why
Maintenance	1.6–2.0g/kg	Standard active-adult recommendation
Lean bulk (surplus)	1.6–2.2g/kg	Supports new muscle synthesis with ample calories available
Cut (deficit)	1.8–2.4g/kg	Higher end needed specifically to protect muscle when calories are limited

For a 75 kg lifter, this means cutting protein targets often land around 135–180g daily — noticeably higher, in relative terms, than what the same person might eat while bulking, even though total calories are lower overall. The protein intake calculator sets this target precisely based on your weight and goal.

Carbs vs. Fat — Which Should You Cut Harder?

With protein fixed at a high, non-negotiable target, the calorie reduction needed for your deficit has to come from carbs and fat. The evidence-based approach is to protect fat at a floor of roughly 20% of total calories — dropping below this risks disrupting testosterone and other hormone production in both men and women — and let carbohydrates absorb the majority of the reduction instead.

Carbs are the most flexible macro to reduce during a cut because they aren't essential in the same biological sense fat and protein are — your body can function well across a wide range of carb intakes, as long as training performance and energy levels are monitored.

That said, dropping carbs too aggressively — particularly for people training hard multiple times a week — can noticeably hurt training performance and recovery, which indirectly threatens muscle retention anyway. The carb calculator helps find a carb floor that still supports your training volume rather than cutting blindly.

How Big Should Your Cutting Deficit Be?

Deficit Size	Weekly Fat Loss	Best For	Trade-off
10–15% below TDEE	~0.25–0.4 kg	Advanced lifters, minimal muscle loss priority	Slow but very muscle-sparing
15–25% below TDEE	~0.4–0.7 kg	Most people — the sustainable sweet spot	Best balance of speed and muscle retention
25%+ below TDEE	~0.7 kg+	Rarely optimal outside short, structured phases	Higher risk of muscle loss, hunger, and adherence failure

Aggressive deficits beyond roughly 25% below TDEE do not meaningfully speed fat loss in a way that outweighs the accelerated muscle loss and adherence risk they carry. The moderate range is the evidence-supported default for the vast majority of cutting phases.

A Worked Cutting Macro Example

28-year-old female, 65 kg, 165 cm, moderately active, intermediate lifter
TDEE: ~2,150 kcal/day
Cutting deficit (20% below TDEE): 2,150 × 0.80 = 1,720 kcal/day

Protein: 65 kg × 2.0g/kg = 130g protein = 520 kcal
Fat: 1,720 × 0.22 = 378 kcal ÷ 9 = 42g fat
Carbs (remainder): 1,720 − 520 − 378 = 822 ÷ 4 = ~205g carbs

Notice that carbs, not protein or fat, are absorbing the entire calorie reduction relative to her maintenance numbers — exactly as the strategy intends. Run your own version with the macro calculator.

A 7-Day Cutting Macro Framework

Day Type	Frequency	Approach
Training days	4–5x per week	Slightly higher carbs to fuel and recover from sessions
Rest days	2–3x per week	Slightly lower carbs; protein and fat stay consistent

Keep protein and fat flat every single day of the week, and let carbs shift modestly higher on training days versus rest days — this small adjustment (often just 20–40g difference) helps fuel performance without meaningfully changing the weekly deficit total.

Adjusting Your Macros as the Cut Progresses

As body weight drops, TDEE drops with it — a cutting plan built on week-one numbers will become progressively too generous a deficit target as weeks pass, or too aggressive if left unadjusted for long enough given metabolic adaptation. Recalculate your TDEE with the TDEE calculator roughly every 3–4 weeks and adjust your macro targets to match the updated number, rather than dieting indefinitely against stale week-one math.

Frequently Asked Questions

Should protein be higher when cutting than when bulking?

In relative terms, yes — cutting protein targets (1.8–2.4g/kg) sit at the higher end of the general range specifically because protein's muscle-protective role becomes more critical when calories are limited. Bulking protein targets can sit slightly lower (1.6–2.2g/kg) since ample calories already support muscle growth.

Is low-carb better than low-fat for cutting?

Neither is inherently superior for fat loss when total calories and protein are matched — research consistently shows comparable results between the two approaches. The practical recommendation to keep fat above roughly 20% and cut carbs more aggressively is based on protecting hormone production, not a fat-loss advantage specific to carbs.

How do I know if my deficit is too aggressive?

Warning signs include rapid strength loss in the gym, persistent fatigue beyond normal training soreness, and weight loss exceeding roughly 1% of body weight per week for several consecutive weeks. Any of these suggest scaling the deficit back toward the moderate 15–20% range.

Do I need to eat different macros on training versus rest days while cutting?

It's not required, but shifting carbs modestly higher on training days and slightly lower on rest days — while keeping protein and fat consistent — can improve training performance and recovery without meaningfully affecting your weekly deficit total.

How long should a cutting phase last?

Most sustainable cuts run 8–16 weeks depending on how much fat needs to be lost, with reassessment of TDEE and macros roughly every 3–4 weeks throughout. Very long uninterrupted cuts increase the risk of both muscle loss and diet fatigue.

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References & Sources

1. Helms, E. R. et al. (2014). Evidence-based recommendations for natural bodybuilding contest preparation. Journal of the International Society of Sports Nutrition, 11, 20.
2. Longland, T. M. et al. (2016). Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss. American Journal of Clinical Nutrition, 103(3), 738–746.
3. Hall, K. D. & Guo, J. (2017). Obesity energetics: body weight regulation and the effects of diet composition. Gastroenterology, 152(7), 1718–1727.
4. MacrosMeasure (2025). Free Calorie Deficit Calculator.
5. MacrosMeasure (2025). Free Macro Calculator.