To burn fat you need to eat less. But at the same time, you want to maintain your hard-earned muscle mass. What is the best ratio of proteins, carbohydrates and fats to use?

FAT LOSS AND ENERGY BALANCE

First the basics. Fat loss is only possible with a negative energy balance: you use more energy than you take in through your diet. Your energy balance (or ‘maintenance’) is the level at which you consume as much energy in a day as you use.

The energy balance is expressed in kilocalories (kcal). This unit is also used on the packaging of nutritional values. Popularly, people usually talk about ‘calories’, while they mean kilocalories.

To find out how many calories you consume each day, calculate your ‘bare’ calorie needs using a formula (Roza and Shizgal), then add your daily ‘extraordinary’ physical activities. With the latter you have to think of physical work, walking and cycling, cardio, strength sports and other sports. See also our step-by-step plan for calculating your energy consumption as accurately as possible.

To calculate your maintenance, you can also go for the quick, but significantly less accurate method: multiply your weight in kg by 33. If you weigh 75 kg, your maintenance is therefore approximately (75 * 33 =) 2500 kcal.

THE PRINCIPLES OF CUTTING

Cutting is bodybuilding jargon for a training cycle that focuses on fat loss. Usually it is the logical sequel to the bulk, the training cycle in which you focus on muscle growth. While bulking, you use a small calorie surplus to facilitate that growth. As a natural, however, it is impossible to build up pure muscle mass; during a bulk, there is always some fat mass added. And you try to get rid of that after the bulk by cutting. This, of course, preferably while preserving the built-up muscle mass.

Because of the latter, cutting is much more difficult than ‘just’ losing weight. To burn as much fat as possible while protecting your muscle mass as much as possible, it is best to cut according to the following rules:

• Maintain an energy deficit of about 20-25% of your maintenance level. With a short cut (‘minicut’) or when using diet breaks, you can use a slightly larger deficit if desired;
• Continue to eat enough protein;
• Keep training. Reduce your training volume if necessary, but certainly not too much – the body must continue to receive sufficient anabolic stimuli to ‘want’ to maintain muscle mass;
• Do some cardio if you’re having a hard time meeting your energy deficit purely through diet, but don’t overdo it. Too much (heavy) cardio can hinder your strength training recovery.

MACRONUTRIENTS IN THE CUT

Macronutrients are the ‘big’ substances in our diet: proteins, carbohydrates and fats. ‘Large’ because they occur in large quantities (grams) in our diet. In addition, there are micronutrients, which are referred to as ‘small’ nutrients such as vitamins and minerals.

Each macronutrient provides a certain amount of energy, namely:

• 1 gram of protein: 4 kcal
• 1 gram carbohydrate: 4 kcal
• 1 gram of fat: 9 kcal

And each macronutrient has its own unique qualities that you need to function optimally. In this article we focus on the qualities that specifically apply to cutting bodybuilders.

PROTEIN

Proteins are the building blocks of muscles. That is why as a bodybuilder you need significantly more protein than a mere mortal. It’s no different in the cut. Your body needs building materials to facilitate muscle protein synthesis, which is necessary to maintain your muscle mass.

While in the bulk a recommendation applies of 1.6 grams of protein per kilogram of body weight per day, in the cut it is even higher: 1.8 grams per kilogram of body weight per day, increasing to 2.7 g/kg/d. The latter applies to bodybuilders with a low fat percentage (< 10%).

We advise you not to go higher in the proteins than 1.8-2.7 g/kg/d. Because although eating more protein in itself is not harmful, it also means that you can eat fewer other macronutrients (carbohydrates and fats), while they are also very important (see below).

And take extra protein to satisfy your hunger? After all, proteins are said to be more satiating than carbohydrates and fats, making you less hungry. But that seems to be the case only to a small extent.

Finally: do not tarry too much on protein powders during the cut. Try to get your protein mainly from nutritious food sources, such as eggs. Moreover, you can already eat so little ‘real’ food.

FATS

The number of calories and the amount of protein are clear, but how do you divide the rest of the calories between carbohydrates and fats? As a bodybuilder, should you go high-carb or high-fat?

Scientists are not yet in agreement on this. Coach Mike Israetel mentions the importance of carbohydrates for muscle growth and maintenance, but his colleague Menno Henselmans contributed to a voluminous meta-analysis that shows that the amount of carbohydrates and fats does not matter much for strength training performance.

A second meta-analysis, by coach Eric Helms, among others, shows that carbohydrates are important for muscle growth, especially eaten before training, but according to a review of the study, by again Henselmans, not as important as often suggested.

Also for fat loss it does not matter how you divide the fats and carbohydrates, large-scale research shows.

According to muscle growth professor Brad Schoenfeld in an interview with Men’s Health, you don’t need as many carbohydrates for resistance training as is often thought. As long as you make sure you’re not low on carbs, someone on a carnivore, keto, or paleo diet may be deficient in glycogen and not maximize muscle growth.

Our opinion? In the bulk, the division of carbohydrates and fats does not matter much, but in the cut it is best to choose a relatively large amount of carbohydrates by cutting back on fats. This will especially benefit your energy during training. Renowned coaches such as Mike Israetel and Eric Texler endorse this. The minimum amount of fat in the cut is between 0.5 and 1 gram per kilogram of body weight per day, which is also confirmed by a review by Eric Helms. Take 0.8 g/kg/d as a starting point and see if you need to adjust up or down from there.

A certain amount of fat is indispensable, among other things for the absorption of vitamins and to maintain your testosterone level. For the latter you need both saturated and monounsaturated fat. And no, you won’t get fat from fat, as long as you stay below your maintenance level overall.

Get your fats for 25-50 percent from saturated fat and divide the rest equally between monounsaturated and polyunsaturated fat. Avoid foods that contain a lot of industrial trans fats, such as snacks.

CARBOHYDRATES

With a protein intake of 1.8-2.7 kg/d and limiting your fat intake to 0.5-1 g/kg/d, the amount of carbohydrates that you can eat automatically arises.

But carbohydrates are fattening, right? No, calories are fattening. Or rather, too many calories. For fat loss, the distribution of fats and carbohydrates is not very relevant, as we have already seen.

HOW DO YOU CALCULATE MACRONUTRIENTS?

For the average person, the best protein/carb/fat ratio is 15-20 / 40-60 / 20-30%. As a bodybuilder it is best not to work with those kinds of percentages, but with absolute intake per gram of body weight. To give you a helping hand, the following step-by-step plan.

1. CALCULATE YOUR DAILY CALORIE REQUIREMENT (‘BARE MAINTENANCE’)

To get a somewhat accurate estimate of your daily calorie requirement, you can use our step-by-step-plan. Most calculators on the internet aren’t accurate, because they estimate physical activity far too broadly.

As an example we use a man of 75 kg with a daily maintenance of 2500 kcal. By ‘maintenance’ we mean the energy requirement excluding strength training, cardio and/or other sports.

Keep in mind that your maintenance decreases slowly during the cut under the influence of metabolic adaptation.

2. CALCULATE YOUR ENERGY BALANCE IN THE CUT

Take 20-25% of your calorie needs and subtract that.

A 25% calorie reduction in our example means a calorie intake of (0.75 x 2500 =) 1875 kcal. On days when you do strength training and/or cardio, you obviously have to add the calories burned with that. In this article you can read about how much you burn with strength training. If that is 450 kcal, an average for an hour of fairly intensive strength training (including afterburn), you have a calorie intake of 1875 + 450 = 2325 kcal that day . If you also add half an hour of cardio on the crosstrainer at 250 kcal, you arrive at  1875 + 450 + 250 = 2575 kcal.

3. CALCULATE YOUR PROTEIN REQUIREMENT

Assuming 1.8 g of protein per kg of body weight per day, the protein requirement is as follows: (1.8 x 75 =) 135 g. That is (135 x 4 =) 540 kcal.

4. CALCULATE YOUR FAT NEEDS

Assuming you don’t eat more than the minimum of ~0.6 g/kg/day, the amount of fat will be:

0.6 x 75 = 45 grams. That is  (45 x 9 =) 405 kcal.

5. CALCULATE YOUR CARBOHYDRATE INTAKE

What remains is your carbohydrate intake. In our example: 1875 – 540 – 405 = 930 kcal, or (930 / 4 =) 232.5 g.

‘OUR’ MACRONUTRIENT RATIO

So our daily nutritional intake during the cut looks like this: We have added the percentages so that you can make a comparison with those for the average person (E 15-20 / K 40-60 / V 20-30 %):

Energy: 1875 kcal
Protein: 540 kcal, 135 g (28%)
Carbohydrates  930 kcal, 232.5 g (50%)
Fats: 405 kcal, 45 g (22%)

DIFFERENCE FROM THE BULK

For comparison, make the same calculation for a bulk situation. A lean bulk that is, with a limited calorie surplus of 250 kcal. In the bulk we assume 2 g protein and 1 g fat per kg body weight. The daily food intake then becomes:

Energy: 2500 + 250 = 2750 kcal
Proteins: 2 gx 75 = 150 g, 600 kcal (22%)
Carbohydrates: 369 g, 1475 kcal (53%)
Fats: 1 gx 75 = 75 g, 675 kcal (25%)

SUMMARIZED

The optimal distribution of macronutrients (proteins/carbohydrates/fats) for bodybuilders mainly depends on the goal: muscle building (bulk), maintenance, fat loss (cut), or muscle building and fat loss (recomp). In addition, things like body type, genetics and age also play a role.

For fat loss while maintaining muscle mass, i.e. cutting, it is best to use the following daily amounts:

• energy (kcal): maintenance minus 20-25%;
• proteins: 1.8-2.7 g per kg of body weight;
• fats: 0.5-1 g per kg of body weight;
• carbohydrates: the rest.

This article was originally published on August 6, 2018 and revised on May 23, 2020. Last updated on July 22, 2022.