How many calories are present in a gram of protein?

A gram of protein contains 4 calories. This is based on the understanding that macronutrients provide energy in specific amounts: carbohydrates also provide 4 calories per gram, while fats offer 9 calories per gram, and alcohol gives about 7 calories per gram. The significance of protein in the diet extends beyond just energy, as it plays a crucial role in building and repairing tissues, producing enzymes and hormones, and supporting overall bodily functions. Therefore, knowing that protein provides 4 calories per gram helps individuals make informed choices regarding their nutritional needs, particularly when managing their energy intake for various health and fitness goals.