What Are Macronutrients? Why Protein, Carbohydrates and Fat Matter for Athletes
Learn what protein, carbohydrates and fat do in the body, how they complement each other, and how to strike the optimal balance as an athlete.
What Are Macronutrients?
There are three basic nutrient groups that cover the body's daily need for energy and building blocks: protein, carbohydrates and fat. The name "macro" comes from the fact that these nutrients are measured in grams; vitamins and minerals, by contrast, are micronutrients.
Protein: The Bricks of Muscle
Protein is made up of amino acids. Muscle fibers that break down during exercise need protein to repair. One gram of protein provides 4 kcal.
Recommended amount for athletes: 1.4–2.0 grams per kilogram of body weight for active people. For those looking to build muscle, this can go up to 1.8–2.2 g/kg.
Good protein sources:
- Eggs (full bioavailability; the reference protein source)
- Chicken breast, turkey
- Cottage cheese, yogurt
- Tuna, salmon
- Lentils, chickpeas (plant-based but incomplete; should be combined with grains)
Carbohydrates: The Primary Fuel
Carbohydrates are the primary fuel source, especially for high-intensity exercise. Muscles store them as glycogen; when these stores run out, performance drops.
One gram of carbohydrate provides 4 kcal.
Before training: Low-fiber, medium-to-high GI carbohydrates (bananas, rice, white bread) eaten 60–90 minutes before exercise top up glycogen stores.
After training: A combination of fast carbohydrates + protein within 30 minutes speeds up muscle synthesis.
Fat: Fuel for Hormones and Long Distances
At 9 kcal per gram, fat is the most concentrated source of energy. But its importance doesn't end there: hormones such as testosterone, estrogen and cortisol are synthesized from fat. In addition, the fat-soluble vitamins A, D, E and K cannot be absorbed without fat.
Avoid: Trans fats (products containing partially hydrogenated fat). Reducing saturated fat is good, but cutting it out completely leads to hormone suppression.
Recommended sources: Olive oil, avocado, hazelnuts, salmon, walnuts.
A Practical Split
| Goal | Protein | Carbohydrates | Fat |
|---|---|---|---|
| Weight loss | 35% | 35% | 30% |
| Building muscle | 30% | 45% | 25% |
| Endurance | 20% | 55% | 25% |
| General fitness | 25% | 45% | 30% |
These ratios are a starting point; individual response varies with age, sex and type of sport.
This article is general information. Talk to a paediatrician or dietitian before deciding on a nutrition plan or supplements for your child.