This document provides an overview of nutrition and the six major classes of nutrients: carbohydrates, fats, proteins, vitamins, minerals, and water. It defines each class and lists examples of nutrients that fall within each class. Carbohydrates are divided into simple and complex categories. Fats are categorized as saturated, unsaturated, monounsaturated and polyunsaturated. The document also discusses balanced diets, metabolism, calories, fiber, essential and nonessential proteins, cholesterol, fat-soluble and water-soluble vitamins, and the importance of water for bodily functions.