Macronutrients: protein, carbs and fat

Protein and carbohydrates give about 4 kcal per gram, fat about 9 kcal per gram. Fiber gives less, about 2 kcal per gram, because gut bacteria break down only part of it.

EFSA gives adults a range of 45 to 60% of calories from carbohydrates and 20 to 35% from fat; the US range for fat is also 20 to 35%. Carbohydrates also have a US RDA of 130 g a day, and protein is set per kg of body weight rather than as a share.

The US RDA is 0.8 g per kg of body weight a day, 60 g for a 75 kg adult, and EFSA sets 0.83 g per kg. Active adults are advised 1.2 to 2.0 g per kg (ACSM, ISSN), and 1.6 to 2.2 g per kg helps keep muscle while dieting or build it (ISSN; Morton et al. 2018). For your own number, use the macro calculator.

Adults aged 19 to 50 need 25 to 38 g a day: the US adequate intake is 25 g for women and 38 g for men, and 21 g and 30 g after 50. EFSA and the WHO advise at least 25 g. Most adults in Europe and the US eat less than that.

The WHO advises keeping free sugars under 10% of daily energy, about 50 g on a 2,000 kcal diet, and suggests under 5% for further benefit. Sugar naturally in whole fruit, vegetables and milk does not count as free sugar.

Eaten in large amounts, it raises LDL cholesterol. The WHO advises keeping saturated fat under 10% of daily energy, about 22 g on a 2,000 kcal diet, and replacing it with unsaturated fats.

No. Alcohol gives about 7 kcal per gram, but the body does not need it, so it is not counted as a nutrient.