将以下段落分成三个自然段。
A healthy diet includes a balance of proteins, carbohydrates, and fats. Protein is essential for building muscle and repairing tissues. Carbohydrates provide energy to fuel the body, and fats are essential for brain function and other bodily processes.
段落重写：

A healthy diet is composed of three essential macronutrients, proteins, carbohydrates, and fats. Proteins are necessary for repairing tissues and building muscle. Carbohydrates serve as fuel to provide the body with energy, whereas fats are crucial for facilitating brain function and other bodily processes.

自然段1: 
A healthy diet is composed of three essential macronutrients, proteins, carbohydrates, and fats.

自然段2: 
Proteins are necessary for repairing tissues and building muscles. 

自然段3: 
Carbohydrates serve as fuel to provide the body with energy, whereas fats are crucial for facilitating brain function and other bodily processes.