What is the primary role of dietary fiber in digestion?

The primary role of dietary fiber in digestion is assisting in bowel regularity. Dietary fiber is composed of plant-based carbohydrates that cannot be digested by the human gastrointestinal system. This indigestible characteristic allows fiber to add bulk to the stool, which helps to facilitate the movement of food through the digestive tract. As fiber passes through the colon, it also helps to retain water, making stools softer and easier to pass, and thus promoting regular bowel movements.

In addition to its role in bowel regularity, dietary fiber can also contribute to other aspects of health, such as helping to prevent constipation and reducing the risk of certain digestive disorders. While fiber does have secondary effects on blood sugar regulation and can play indirect roles in body weight management or caloric intake, its most direct and significant impact on digestion is ensuring smooth passage of waste through the intestines.