Which of the following is NOT a category of carbohydrates?

Carbohydrates are classified into three main categories: monosaccharides, disaccharides, and polysaccharides. Monosaccharides are the simplest form of carbohydrates, consisting of single sugar molecules like glucose and fructose. Disaccharides are formed when two monosaccharides are joined together, such as sucrose and lactose. Polysaccharides consist of long chains of monosaccharides and serve as storage forms of energy (like starch) or structural components (like cellulose).

Since proteins are a separate macronutrient made up of amino acids, they do not belong to the carbohydrate category. The distinction between these macronutrients is important for understanding nutrition, as each serves different functions in the body.