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Macros

Understanding Macronutrients

Protein, carbohydrates and fat provide the energy in your diet. Learn what each one does, how to read the numbers and how to find a balance that suits you.

By FitNumbra Editorial TeamPublished 3 min read

Macronutrients — “macros” — are the nutrients your body needs in large amounts: protein, carbohydrates and fat. They provide energy (calories) and the building blocks your body uses every day.

You do not need to track macros to eat well, but understanding them makes it much easier to read food labels and plan balanced meals.

How many calories each macro provides

MacronutrientEnergy per gram
Proteinabout 4 kcal
Carbohydrateabout 4 kcal
Fatabout 9 kcal
Alcohol (not a nutrient)about 7 kcal

Example: a snack with 10 g protein, 20 g carbohydrate and 5 g fat provides roughly 40 + 80 + 45 = 165 kcal.

Protein

Protein provides amino acids that your body uses to build and repair muscle and other tissues, make enzymes and hormones and support immune function. It is also the most filling macronutrient for many people.

Good sources include poultry, fish, eggs, dairy, legumes, tofu and tempeh. See How much protein do you need? for daily targets.

Carbohydrates

Carbohydrates are the body’s preferred fuel for high-intensity exercise and the brain’s main energy source. They include sugars, starches and fibre.

  • Choose mostly whole grains, vegetables, fruit and legumes, which also provide fibre, vitamins and minerals.
  • Limit added sugars and refined grains.
  • Fibre supports digestion and helps you feel full — many adults eat less than recommended.

Fat

Dietary fat supplies essential fatty acids, helps you absorb vitamins A, D, E and K, and plays a role in hormone production. Because it provides 9 kcal per gram, portions of high-fat foods add up quickly.

  • Favour unsaturated fats from olive oil, nuts, seeds, avocado and oily fish.
  • Keep saturated fat moderate and avoid industrial trans fats.

Recommended macronutrient ranges

The US National Academies’ Acceptable Macronutrient Distribution Ranges (AMDR) for adults are:

MacronutrientShare of daily calories
Protein10 – 35%
Carbohydrate45 – 65%
Fat20 – 35%

How to set your own macros

A simple method
1. Choose a daily calorie target
2. Set protein by body weight (e.g. 1.6 g/kg)
3. Set fat as a share of calories (e.g. 30%)
4. Fill the remaining calories with carbohydrates

Example: 2,000 kcal and 70 kg. Protein 1.6 × 70 = 112 g (448 kcal). Fat 30% = 600 kcal ≈ 67 g. Carbohydrates fill the remaining 952 kcal ≈ 238 g.

Try the calculators

Put this guide into practice with a free estimate.

Frequently asked questions

What is the best macro ratio for weight loss?

Total calories matter most for weight loss. Within that, a higher protein intake can help preserve muscle and control hunger. The best ratio is one you can maintain.

Are carbs bad for you?

No. Carbohydrates from whole grains, fruit, vegetables and legumes are part of most healthy diets. Refined carbohydrates and added sugars are worth limiting.

Is fibre a macronutrient?

Fibre is a type of carbohydrate. Most of it is not digested in the usual way, so it provides fewer calories than other carbohydrates, but it has important benefits for digestion and fullness.

Methods and sources

Nutrition

How Much Protein Do You Need?

Protein needs depend on your weight, activity and goals. Here is what the research says, with simple examples and food ideas.

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Calories

How Many Calories Do You Need Per Day?

Your daily calorie needs depend on your size, age, sex and how active you are. Here is how to estimate them — and how to adjust based on real results.

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Weight Management

What Is BMI and How Is It Calculated?

Body Mass Index is a quick screening number based on height and weight. Here is how it is calculated, what the categories mean and where BMI falls short.

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