Carbs, Fat, Protein: Macros Explained Simply

What each macro actually does

Carbohydrates are the fuel. Your brain and muscles run mainly on glucose. You find them in bread, rice, pasta, potatoes, fruit, legumes — and in sugar in all its forms. "Complex" carbs (starches) and "simple" carbs (sugars) aren't equal: the former give you steady energy, the latter a spike followed by a crash.

Fat isn't the enemy. Your body needs it to make hormones, build cell membranes and absorb vitamins A, D, E and K. Olive oil, butter, avocado, nuts, oily fish: these are useful foods, not slip-ups.

Protein is the building material: muscles, skin, hair, enzymes. It's also the most satiating macro — for the same calories, you're less hungry after a protein-rich meal. To find out how much you need for your weight, we broke down the g/kg calculation in how much protein per day.

4 and 9: the only two numbers to remember

Each macro has a fixed calorie density:

• 1 g of carbohydrate = 4 kcal
• 1 g of protein = 4 kcal
• 1 g of fat = 9 kcal

That's the whole magic (and trap) of fat: more than double the energy per gram. A tablespoon of oil is about 14 g of fat, so around 120 kcal — as much as a thick slice of bread, in a volume ten times smaller. Neither good nor bad: just dense. For reference, alcohol provides 7 kcal/g, without being a useful macro.

A food's calorie count is simply the sum: 4 × grams of carbs + 4 × grams of protein + 9 × grams of fat. Once you understand that, labels have no more secrets.

The usual split, according to ANSES

ANSES (the French health agency) gives benchmarks as a percentage of your day's calories, what it calls total energy intake:

• Carbohydrates: 40 to 55% of calories, according to its report on nutritional references, favouring complex carbs and fibre.
• Fat: 35 to 40% of calories, according to its fact sheet on fats. Yes, over a third of your calories from fat is the official benchmark.
• Protein: 10 to 20% of calories, according to its fact sheet on protein.

A concrete example on 2,000 kcal a day: that's 200 to 275 g of carbs, 78 to 89 g of fat and 50 to 100 g of protein. The starting point is your calorie need — if you don't know it, start by calculating your TDEE.

Notice how wide the ranges are: 40 to 55% for carbs is huge. These aren't gram-precise rules, they're zones within which most reasonable splits fit. No need to aim for exactly 47.3%. Also note that these three ranges don't stack at their maximum: they're not meant to be maxed out at the same time. Aim for a combination that adds up to roughly 100% of your calories — for example, if you're near the top for fat (40%), you'll naturally land lower on carbs or protein, not at their own top end simultaneously.

The three classic traps

1. Fear of fat. Decades of "0%" products have planted the idea that fat inherently makes you gain weight. Yet the ANSES benchmark sits at 35-40% of calories. The real problem with "0%" is that it's often compensated with sugar or additives to stay edible. A plain full-fat yoghurt beats most low-fat desserts.

2. Hidden sugars. ANSES recommends not exceeding 100 g of sugar per day for an adult, and no more than one sugary drink. A 33 cl can of soda already contains about 35 g — more than a third of that ceiling, in a single drink. The rest slips into sauces, breakfast cereals, ready meals and juices without you noticing.

3. Over-marketed protein. The word "protein" sells, so it's everywhere: bars, spreads, cereals, pizzas. Look at the numbers before the marketing: a "high-protein" bar at 8 g often costs more than two eggs, which provide 12 to 13 g. Protein is found first in whole foods: eggs, fish, chicken, skyr, lentils, tofu.

A calorie is not just a calorie

100 kcal of lentils and 100 kcal of soda weigh the same on your daily total. But one gives you fibre, iron, protein and several hours of fullness; the other, sugar and hunger that returns within the hour. Macros only tell part of the story: behind them are the micronutrients — vitamins, minerals, fibre — that make the difference between eating well and just hitting a number.

That said, you don't need to analyse every food. The Nutri-Score already does much of the sorting between two products on the same shelf: we explain how it's calculated (and its limits) in Nutri-Score explained.

Tracking your macros without overthinking it

Three tips to keep it simple:

• Aim for ranges, not exact numbers. Being "in the zone" 5 days out of 7 beats one perfect day followed by giving up.
• Start with protein. It's the macro most often too low, and the one that changes satiety the most. The other two tend to fall into place behind it.
• Let an app do the math. Nobody multiplies grams by 4 and 9 in their head at every meal.

Radish shows your three macros automatically for every food you add, with the Nutri-Score right next to it. Everything works counting without a connection, with no account and no ads: your numbers stay on your phone, never sold.

General information, not medical advice. If in doubt or if you have specific needs, talk to a healthcare professional.

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