What term describes the non-digestible part of plants?

• A. Dietary fat
• B. Dietary fiber
• C. Dietary protein
• D. Dietary carbohydrate

Answer: (B)

Non-digestible plant material is known as dietary fiber. Humans don’t have the enzymes to break down many of the plant polymers like cellulose, hemicellulose, and lignin, so these components pass through the digestive system largely intact. That makes dietary fiber essential for adding bulk to stool and supporting gut health. Fiber also includes soluble types that dissolve in water and form a gel, which can slow digestion and help with cholesterol and blood sugar control, and insoluble types that speed up intestinal transit. You’ll find fiber in fruits, vegetables, whole grains, and legumes. In contrast, fats, proteins, and most carbohydrates are digested and absorbed for energy and body-building, so they aren’t the non-digestible part of plants.