How many calories are in a gram of protein?

Protein provides 4 calories per gram, which is a fundamental concept in nutrition. This caloric value is derived from the structure and metabolism of protein in the body. When consumed, protein is broken down into amino acids, which the body uses for various functions, including muscle repair, enzyme production, and supporting the immune system.

Understanding the caloric contribution of protein is crucial for dietary planning and managing macronutrient ratios within a diet. The knowledge of how many calories come from each macronutrient—protein, carbohydrates, and fats—enables individuals to better balance their intake based on their energy needs and fitness goals. For example, if someone is aiming for a higher protein diet for muscle building or weight loss, knowing that protein contributes 4 calories per gram helps them calculate their calorie intake accurately.