How to calculate your macros for muscle gain or definition: protein per kilo, minimum fats, and carbohydrates based on your training. With an example for 75 kg.

Calories determine whether you gain or lose weight. Macros determine what that change is made of: muscle or fat. Therefore, if you strength train, counting only calories falls short. Here are the rules we use to distribute protein, fats, and carbohydrates according to your goal, and a complete example. If you prefer the direct result, the macro calculator does it with your data.

The correct order: calories, protein, fat, carbohydrates

Most errors come from starting with percentages (“40-30-30”). Percentages don’t know how much you weigh. What works is to set the grams in this order:

Total calories according to the goal (slight surplus for muscle gain, moderate deficit for definition).
Protein in grams per kilogram of body weight.
Fats with a minimum that should not be lowered.
Carbohydrates with what’s left, adjusted to how much you train.

Step 1: Calories

Calculate your daily expenditure (basal metabolism multiplied by activity factor; you have the formula and calculator in calculate daily calories).

Muscle gain: add between 200 and 300 kcal. More surplus does not build more muscle, only more fat. A realistic rate is to gain 0.25 kg per week if you’ve been training for a short time and much less if you’ve been training for years.
Definition: subtract between 300 and 500 kcal. A larger deficit sacrifices muscle, which is precisely what you want to preserve.

Step 2: Protein

It’s the macro that is non-negotiable. The references that work best for people who strength train:

In definition, it is increased because the deficit increases the risk of muscle loss and because protein is more satiating than anything else. If you have a lot of weight to lose, use your target weight instead of your current weight to avoid inflating the figure.

Step 3: Fats

Minimum 0.8 g per kilo of weight per day, and generally between 20% and 30% of calories. Below that, hormones, vitamin absorption, and mood decline. Olive oil, avocado, nuts, whole egg, oily fish.

Step 4: Carbohydrates

What’s left after protein and fat. They are the fuel for training: the more days you train and the harder, the more carbohydrates you need to perform and recover. If you strength train four or five days, it doesn’t make sense to lower them too much, even in definition. Place them around your workout (the meal before and after) and you’ll notice the difference.

Example: 75 kg, strength trains 4 days

Estimated expenditure with moderate activity: about 2,700 kcal (30-year-old man, 178 cm).

For muscle gain (2,950 kcal):

| Macro | Grams | Calories | Percentage | |—| | Protein | 150 g (2 g/kg) | 600 | 20 % | | Fats | 85 g | 765 | 26 % | | Carbohydrates | 395 g | 1,585 | 54 % |

For definition (2,250 kcal):

| Macro | Grams | Calories | Percentage | |—| | Protein | 165 g (2.2 g/kg) | 660 | 29 % | | Fats | 65 g | 585 | 26 % | | Carbohydrates | 250 g | 1,005 | 45 % |

Notice that the percentages come out on their own at the end and are different in each case. That’s what a fixed “40-30-30” split cannot do.

How to reach those grams in real life

165 g of protein can seem daunting until you distribute it: 30-40 g per meal across four meals and a snack. A plate of chicken breast with rice and broccoli provides about 48 g; a Greek yogurt with nuts, 13 g; a protein shake with banana, 28 g. With that and a breakfast with eggs, you’re already close.

For carbohydrates, you don’t need to weigh the rice every day. It’s enough to know that a plate of whole wheat pasta with turkey is around 60-70 g and a medium potato, about 30 g. Check it the first few days; after that, your eye will get used to it.

The most common mistakes we see

Huge surplus “to gain faster.” You gain fat, and then a long definition phase is needed.
Cutting carbohydrates in definition. Performance decreases, training volume decreases, and with it, the stimulus to maintain muscle.
Counting protein from everything. The 8 g of protein from whole wheat bread counts, but the quality is not the same. Prioritize complete sources: egg, dairy, meat, fish, legumes with cereal, soy.
Changing macros every week. Give the plan six or eight weeks and adjust based on weight trends and gym scales (the kilos you lift), not by feel.

And a nutritionist’s note

These figures are for healthy adults who train. With kidney, liver, or metabolic pathologies, the amount of protein should be determined by a professional. The nutritionists at Vitasane, who are behind Fotorie, work daily with athletes, and that criterion is what the app applies: when you set “muscle gain” as a goal, it distributes macros with these rules, and when you take a picture of your plate, it tells you how much protein you need to reach your daily goal.

Macro Calculator for Muscle Gain or Definition