Which of the following is a major source of dietary fiber?

Oatmeal is a major source of dietary fiber, which is crucial for maintaining digestive health and promoting regular bowel movements. Fiber helps to add bulk to the stool, which can prevent constipation and facilitate the smooth passage of food through the intestines. It is also beneficial for managing blood sugar levels and can aid in lowering cholesterol levels.

Oatmeal, being a whole grain, provides both soluble and insoluble fiber. Soluble fiber can help to slow the absorption of sugar and can bind to cholesterol in the digestive system, while insoluble fiber helps to move things along in the digestive tract. Including oatmeal as part of a balanced diet can support overall health and wellness, making it an excellent choice for individuals looking to increase their fiber intake.

In contrast, white rice is a refined grain that has had the bran and germ removed, which significantly reduces its fiber content. Fish and butter contain virtually no dietary fiber, as they are primarily sources of protein and fat, respectively. Therefore, oatmeal clearly stands out as the best option among the choices provided when considering sources of dietary fiber.