What are macros (macronutrients)?

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Macros is short for carbohydrate, protein and fat: the three nutrients the body needs in large amounts and that provide calories.

What are macros (macronutrients)?
The 'macro ratio' in every diet talk
At the gym you often hear people say they 'hit their macros'. Food labels always list carbohydrate, protein and fat. What exactly are macros, and why do people talk about them so much?
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The three nutrients that give calories
In Korean, macros are called 'tan-dan-ji', from the first sounds of carbohydrate, protein and fat. All three give the body energy (calories), and the body needs them in large amounts, so they are called macronutrients.
Why 'macro'
We eat hundreds of grams a day
Vitamins and minerals are also essential, but the body needs only tiny amounts, so they are called micronutrients. Macros are eaten in grams. For someone eating 2,000 kcal a day within Korea's recommended ranges, carbohydrate alone is about 250-325 g.
Carbohydrate
Sugars, starch and fiber
The sugars in fruit and milk and the starch in rice, bread and potatoes are broken down in the body into glucose. Glucose travels in the blood and becomes energy the body can use right away. Fiber is not broken down; it passes through the gut and adds bulk to stool.
Protein
Material to repair and build the body
Protein is a long chain of small pieces called amino acids. Protein you eat is broken down into amino acids, which then become material to repair cells and make new ones. Meat, fish, eggs, milk and beans are rich in it.
Fat
The nutrient with the most energy
Fat gives about 9 kcal per gram, more than twice as much as carbohydrate or protein (about 4 kcal). It is the body's main fuel at rest and during long, light activity. It is found in meat, butter, cooking oil and nuts.
Macro ratio
Each nutrient's share of daily calories
The macro ratio shows, in percent, how much of the day's calories comes from each nutrient. If you eat 2,000 kcal a day and 400 kcal of it comes from protein, protein makes up 20%.
Korea's recommended ranges
Carbs 50-65%, protein 10-20%
These are the ranges the 2025 Dietary Reference Intakes for Koreans give for adults: the share of daily calories each nutrient should take. Fat is 15-30%. Within these three ranges, you can choose a ratio that fits your own diet.
Common myth
Is less fat always better?
No. Fat includes essential fatty acids, which the body cannot make and must get from food. Vitamins A, D, E and K are taken into the body well only when fat is present. A diet with too little fat leaves you short of both.
Summary
The three nutrients that give calories
Macros are carbohydrate, protein and fat: nutrients the body needs in large amounts and that give calories. Fat is also an essential nutrient, not something to avoid completely. Related terms: calorie, amino acid, fiber.