Which of the following nutrients does NOT provide energy to the body?

Fiber is the correct answer because it is classified as a type of carbohydrate, but it is unique in that it is not digested and absorbed by the body in the same way that other carbohydrates are. While fats, proteins, and carbohydrates all provide calories that the body can use for energy—fats provide 9 calories per gram, and both proteins and carbohydrates provide 4 calories per gram—fiber passes through the digestive system largely intact and does not yield energy in the form of calories.

Fiber plays a crucial role in digestive health by aiding in regular bowel movements, but it does not contribute energy like other macronutrients. This characteristic distinguishes fiber from fats, proteins, and carbohydrates, which can be metabolized for energy.