Foods that maintain and build muscle and are used as an energy source during stress are known as what?

The correct answer is proteins, as they play a critical role in building and repairing tissues, especially muscle. During times of stress, the body can utilize proteins as an energy source, particularly when carbohydrate stores are depleted. Proteins are made up of amino acids, which are essential for various bodily functions, including muscle synthesis and recovery after exertion.

In the context of nutrition, while carbohydrates provide quick energy and fats serve as a long-lasting energy source, proteins specifically support muscle growth and overall strength. They are crucial in situations of physical stress, such as intense exercise or recovery from injury, as the body requires additional protein to repair and build muscle tissues. Thus, understanding the role of proteins in not just muscle development but also as a potential energy source underscores their importance in maintaining physical health and performance.