What is the main health benefit of dietary fiber?

Dietary fiber is primarily known for its role in aiding digestion and promoting bowel regularity. It helps to add bulk to the stool, which facilitates the movement of food through the digestive tract and can prevent constipation. By promoting regular bowel movements, fiber can help maintain a healthy digestive system and reduce the risk of developing gastrointestinal issues.

While fiber can have secondary effects, such as influencing cholesterol levels and possibly contributing to overall skin health, its primary and most significant health benefit lies in its ability to support digestive health. This makes option C the most accurate choice in this context. Additionally, dietary fiber does not have a role in increasing muscle mass, which is why that option does not align with the primary benefits of fiber.