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

To set macros for a cut, choose a moderate calorie deficit first, set protein next, give fat a modest share of calories, and let carbohydrates fill whatever is left. The exact ratio matters much less than the calorie total and a consistent protein intake.

Step 1: set your calories

Macros are a way of splitting a calorie target, so the target comes first. Start from an estimate of your maintenance calories (what you burn in a normal day) and eat somewhat less than that.

How much less is the part people get wrong. A review of evidence for natural bodybuilders preparing for competition recommends a calorie intake that produces losses of about 0.5 to 1% of body weight per week to maximize muscle retention. A separate meta-analysis of resistance training studies concluded that people lifting to keep muscle while losing weight should avoid deficits larger than about 500 calories a day. Our guide on how to lose fat without losing muscle covers why a moderate deficit protects muscle.

Step 2: set protein first

Protein is the macro that does the most to protect muscle while you diet, so it gets set before fat and carbs.

• The International Society of Sports Nutrition says 1.4 to 2.0 grams per kilogram of body weight a day is enough for most exercising people to build and keep muscle.
• The same position stand notes that higher intakes, 2.3 to 3.1 grams per kilogram, may be needed to keep the most lean mass in resistance-trained people who are eating below maintenance.
• The bodybuilding review above lands in a similar place, recommending 2.3 to 3.1 grams per kilogram of lean body mass for most competitors.

If those numbers feel abstract, our guide on how much protein you need to lose weight converts them to pounds and explains where they come from. How you spread that protein across the day is covered in how much protein per meal.

Step 3: give fat a modest share

After protein, set fat. The bodybuilding review recommends 15 to 30% of calories from fat for most competitors during contest preparation. Fat is calorie-dense (9 calories per gram, versus 4 for protein and carbohydrates), so each gram costs more of your budget, but cutting it to almost nothing is not the goal either.

Step 4: let carbs fill the rest

Carbohydrates take whatever calories remain after protein and fat. The same review recommends the remainder of calories from carbohydrate. Carbs fuel training, so on a cut they usually shrink the most, but they do not need to go to zero.

A worked example

Take someone who weighs 80 kg (about 176 lb) and whose cut calls for 2,000 calories a day:

1. Protein: 2.0 g per kg is 160 g, or 640 calories.
2. Fat: 25% of 2,000 calories is 500 calories, or about 56 g.
3. Carbs: 2,000 minus 640 minus 500 leaves 860 calories, or 215 g.

Those numbers are an illustration of the method, not a prescription. Your own targets depend on your body, your training, and how fast you are trying to lose.

Does the macro ratio matter?

Less than people think. In a two-year trial of 811 adults published in the New England Journal of Medicine, four reduced-calorie diets with very different shares of fat, protein, and carbohydrates produced similar weight loss. The authors concluded that reduced-calorie diets result in meaningful weight loss regardless of which macronutrients they emphasize.

That does not mean protein is irrelevant. It means that for the number on the scale, calories do most of the work, while protein and resistance training decide how much of the loss is fat rather than muscle.

What about 40/40/20?

"40/40/20" is a popular shorthand for a fixed split, most often 40% of calories from protein, 40% from carbohydrates, and 20% from fat. It can work, and its 20% fat sits inside the 15 to 30% range above. The weakness of any fixed percentage is that protein then rises and falls with your calories instead of being set from your body weight. Setting protein in grams first and splitting the rest is more precise.

Where Metriq fits

Metriq follows the same order. It sets your calorie target from your estimated maintenance and your chosen pace (15, 20, or 25% below maintenance on a fat-loss plan), and never below 1,200 calories. Protein is set from your body weight, or from an adjusted weight if your body fat is above 30%. Fat is set at 22.5% of calories, and carbohydrates take the rest, with a minimum of 50 g. Your targets are recalculated from your latest weekly weigh-in. See My Numbers →

Frequently asked questions

How do I calculate my macros for a cut?

Set a calorie target a moderate amount below maintenance, then set protein in grams from your body weight, give fat about 15 to 30% of calories, and give carbohydrates whatever calories remain. Divide protein and carb calories by 4 and fat calories by 9 to get grams.

What should my macro ratio be for cutting?

There is no single best ratio. A large trial found similar weight loss across diets with very different ratios at the same calorie level. Getting enough protein and keeping a moderate deficit matters more than the exact split.

What does the 40/40/20 macro rule mean?

It is a common shorthand for 40% of calories from protein, 40% from carbohydrates, and 20% from fat. It is one workable split, not a rule backed by a specific trial.

Should I cut carbs or fat on a cut?

Keep protein steady and take most of the cut from carbs and fat, without driving either to zero. A sports nutrition review recommends 15 to 30% of calories from fat and the rest from carbohydrate for most people preparing for a physique contest.

How fast should I lose weight on a cut?

A review for natural bodybuilders recommends about 0.5 to 1% of body weight per week to maximize muscle retention. Slower tends to protect more muscle than faster.

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This article is educational and general in nature. It isn't personalized medical or nutrition advice. Talk with a qualified professional before starting or changing a diet or training program, and talk with your prescriber if you take a medication that affects appetite or weight.

Related: How Much Protein Do You Need to Lose Weight? · How to Lose Fat Without Losing Muscle · How Much Protein Per Meal? · Back to the blog

Sources

• Weekly loss of about 0.5 to 1% of body weight; protein 2.3 to 3.1 g/kg of lean body mass; 15 to 30% of calories from fat; remainder from carbohydrate (Helms, Aragon & Fitschen, 2014, Journal of the International Society of Sports Nutrition): pubmed.ncbi.nlm.nih.gov/24864135
• Protein 1.4 to 2.0 g/kg/day for most exercising people; 2.3 to 3.1 g/kg/day may be needed to maximize lean mass retention during hypocaloric periods (Jäger et al., 2017, ISSN position stand: protein and exercise): pubmed.ncbi.nlm.nih.gov/28642676
• People training to preserve lean mass during weight loss should avoid energy deficits above about 500 calories a day (Murphy & Koehler, 2022, Scandinavian Journal of Medicine & Science in Sports, meta-analysis and meta-regression): pubmed.ncbi.nlm.nih.gov/34623696
• Similar weight loss on four reduced-calorie diets with different fat, protein, and carbohydrate shares, 811 adults over two years (Sacks et al., 2009, New England Journal of Medicine): pubmed.ncbi.nlm.nih.gov/19246357