Macronutrients consist of protein, carbohydrate, and fat. They are the nutrients that make up the calories that we consume. 1 gram of both protein and carbohydrate equals 4 calories. 1 gram of fat equals 9 calories. It is wise to work out what macronutrient intake is best for you, instead of just counting calories. This is because often times your total calorie intake may be sufficient to gain or lose weight but your protein for example may be under an effective intake to build and maintain muscle.
In simple terms, the role of protein is to provide amino acids to the body that are essential to repair and rebuild the body. Most importantly to us health and fitness enthusiasts, this includes the building of muscle.
Carbohydrate by default provides the body with its preferred source of energy. The carbohydrates we consume are converted to glycogen and stored in the muscle and liver to be used when necessary. Carbohydrates are particularly important to active people however they are not considered essential, as your body is capable of utilising fat for energy, and in less than ideal situations, protein as well.
Fat is an essential nutrient to the body and plays a large role in hormone production and nutrient transport. This includes the production of testosterone and optimal libido levels which are vital in the building of muscle and general well being.
Because protein and fat are both essential to the body, we need to ensure that adequate quantities are consumed for our desired body composition goals and general health. This is why I suggest consuming 2.5g of protein per kilo of lean body mass and a general total of 20-30% of total calories from fat. The rest of the calories consumed will come from carbohydrate and will make up a large percentage of total calories when eating to grow and a lower percentage when looking to reduce body fat.
Consider macronutrients when designing a meal plan or diet specific to your personal needs rather than just counting calories or following basic nutrition guidelines.