Nutrition basics

Macronutrients Explained: Protein, Carbs & Fat

~5 min read

Calories tell you how much energy is in your food; macronutrients tell you what that energy is made of. There are three: protein, carbohydrates, and fat. Get a feel for what each one does and meal choices get a lot simpler.

Calories per gram

• Protein — 4 calories per gram
• Carbohydrates — 4 calories per gram
• Fat — 9 calories per gram

Fat is the most calorie-dense, which is why oils, nuts, and cheese add up quickly. (Alcohol, for the record, has 7 calories per gram — not a macro, but it counts.)

Protein: the builder

Protein repairs and builds muscle, supports immunity, and is the most filling macro — it keeps you satisfied and protects muscle when you’re losing weight. Aim for roughly 1.6–2.2 g per kg of body weight if you’re active. Sources: chicken, fish, eggs, dairy, legumes, tofu.

Carbohydrates: the fuel

Carbs are your body’s preferred energy source, especially for the brain and hard exercise. Favour mostly fibre-rich, slower carbs — oats, beans, fruit, vegetables, whole grains — over sugary, refined ones that spike and crash. Carbs aren’t the enemy; quality and quantity are what matter.

Fat: the regulator

Dietary fat supports hormones, brain health, and the absorption of vitamins A, D, E, and K. Don’t fear it — but because it’s calorie-dense, keep an eye on portions. Lean toward unsaturated sources: olive oil, nuts, seeds, avocado, and fatty fish.

A simple way to set your macros

• Protein first — set it by body weight (above), the anchor of your plan.
• Fat next — about 0.8–1 g per kg of body weight.
• Carbs fill the rest — whatever calories remain after protein and fat.

A common starting split is roughly 30% protein / 40% carbs / 30% fat — but treat it as a guide, not a rule.

Calories still come first

Macros decide your body composition, energy, and how full you feel — but for weight change, total calories lead. Nail your calorie target, hit your protein, then split the rest in a way you enjoy and can keep up.