25-40. When you eat a healthy diet rich in whole grains, vegetables, and fruits, you usually get most of the fiber youll need, which means youll also be lowering your risk of diabetes, heart disease, diverticulitis, and constipation. Officially, fiber is a type of carbohydrate that the body cant digest. Most adult women should shoot for over 20 grams of fiber a day; men should shoot for over 30 grams. Great sources are whole fruits and vegetables, whole grain breads and breakfast cereals, and all manner of beans. High intake of dietary fiber has been linked to a lower risk of heart disease in a number of large studies that followed people for many years. Cereal fiber, which is found in grains, seemed particularly beneficial. Fiber intake has also been linked with reduced risk of metabolic syndrome, a constellation of factors that increases the chances of developing heart disease and diabetes. These factors include high blood pressure, high insulin levels, excess weight (especially around the abdomen), high levels of triglycerides, the bodys main fat-carrying particle, and low levels of hdl (good) cholesterol. Several studies suggest that higher intake of cereal fiber and whole grains may somehow ward off this increasingly common syndrome.