Macronutrients: protein, carbs, fat
4 calories per gram, or 9? The basic reference points on macronutrients, no meal plan or personalised advice.
Calories per gram
| Macronutrient | Calories / gram |
|---|---|
| Carbohydrates | 4 kcal |
| Protein | 4 kcal |
| Fat | 9 kcal |
| Alcohol | 7 kcal |
Fat packs more than double the calories per gram of carbs or protein — a useful way to understand why fatty foods are more calorie-dense at the same weight.
What each macronutrient is mainly for
| Macronutrient | Main role |
|---|---|
| Carbohydrates | Main quick energy source, especially for the brain and intense effort |
| Protein | Building and repairing tissue (including muscle), enzymes, hormones |
| Fat | Energy reserve, absorption of fat-soluble vitamins (A, D, E, K), hormones |
Calculating calories from a label
Calories = (carbs × 4) + (protein × 4) + (fat × 9)
Useful to double-check a nutrition label or estimate the calories of a homemade dish when you know its composition.
Common sources
| Macronutrient | Common sources |
|---|---|
| Carbohydrates | Grains, bread, pasta, fruit, legumes |
| Protein | Meat, fish, eggs, legumes, dairy |
| Fat | Oils, nuts, avocado, fatty fish, butter |
These are general reference points: needs vary by person, goal and activity level — a healthcare professional or dietitian remains the reference for personalised advice.
Micronutrients: the distinction
Unlike macronutrients (needed in grams, an energy source), micronutrients — vitamins and minerals — are needed in very small amounts (mg or µg) and contribute no calories, yet remain essential to how the body functions (immunity, bone formation, nerve signalling…).
Fibre: the special case among carbs
Fibre is technically a carbohydrate, but isn't digested the same way: it provides about 2 kcal/g (instead of 4) and doesn't raise blood sugar like other carbs do. It's often broken out separately on nutrition labels ("carbohydrates, of which fibre").
Calorie density: a practical guide
| Food | Approximate calorie density |
|---|---|
| Leafy vegetables | Low (lots of volume, few calories) |
| Fruit | Low to moderate |
| Cooked starches | Moderate |
| Nuts, fried food | High (little volume, many calories) |
At equal weight, a food rich in water and fibre (vegetables) often fills you up more than a calorie-dense, low-volume food (fried food, nuts) — useful to know, without being an absolute rule.
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