Macros explained — protein, carbohydrates and fats in nutrition

Macronutrients (macros) are the three main categories of nutrients that provide energy: protein, carbohydrates and fats. Each gram provides a specific caloric value and serves distinct functions in the body.

The three macros

• Protein (4 calories/gram): builds and repairs muscle tissue, produces enzymes and hormones, highly satiating. Essential for body composition change.
• Carbohydrates (4 calories/gram): primary energy source, particularly for high-intensity exercise. Stored as glycogen in muscles and liver.
• Fats (9 calories/gram): hormone production, vitamin absorption (A, D, E, K are fat-soluble), cell membrane integrity. Highly satiating.

Practical application

For most people, eating adequate protein (1.6–2.2g/kg bodyweight for active individuals) and sufficient calories from a varied diet of whole foods is more important than precise macro tracking. Tracking macros is useful for specific performance goals or when previous intuitive eating hasn't achieved desired body composition.