There are two kinds of fibers, water-soluble and water-insoluble. Both are necessary for good health. Water-soluble fibers have been shown to help lower blood cholesterol levels when included in a low-fat diet. Low-density lipoprotein (LDL) cholesterol levels appear to drop more than with a low-fat diet alone.

In addition, these fibers slow the rate of digestion, which in turn increases the rate of absorption. The longer a food is in the intestines, the more nutrients can be absorbed from it.

Oats have the most soluble fiber of any grain, followed by barley and brown rice. Soluble-fiber can also be found in legumes, citrus, berries, and apples.

Insoluble fiber, such as cellulose, comes from the skin, stems, and seeds of plants. It is linked to lowered risk and slower progression of cardiovascular disease. And because it keeps waste moving through the intestines, it may help prevent colon cancer by reducing the time cancer-causing agents are in the intestine.

Fiber swells up as it absorbs water, which delays the emptying of the stomach. Not only is this good for absorption, but it makes you feel full longer. The extra chewing it takes slows down your meal too, which gives your stomach time to tell your brain it’s full.

Bran and any whole-grain food that still includes its outer hull, such as brown rice, are good sources of insoluble fiber. Nuts, fruit in its skin, and vegetables, including cabbage, celery, carrots, beets, and cauliflower, are also excellent sources.