Which of the following is NOT a major nutrient class?

The correct answer is oils, as they are not classified as a major nutrient class in the same way that proteins, carbohydrates, and water are. Major nutrient classes typically include macronutrients, which are essential for providing energy and building blocks for the body. Proteins and carbohydrates are two of these macronutrients that play crucial roles in bodily functions, including tissue repair and energy metabolism. Water, while not a nutrient in the sense of providing energy or structural components, is essential for hydration and the proper functioning of all bodily processes, thus often being included in considerations of major nutrients.

Oils, on the other hand, fall under the category of fats. While fats are indeed important for various bodily functions and can provide energy, they are not typically grouped with the primary classifications of nutrients in basic nutritional science. Instead, oils are considered sources of fat, and fats can be classified into different types, including saturated, unsaturated, and trans fats. Hence, while fats are necessary for health, oils themselves do not represent a major nutrient class.