A: Most whole grains contain fiber but not all high fiber grains are whole, which limits their health-promoting benefits.

Whole grains are left in their natural state with all parts intact - the germ, bran, and endosperm. They contain at least double (and up to six times) the magnesium, potassium, selenium, and phytonutrients of refined grains. When the outer layers of the grain are stripped off in processing (refining), these powerful nutrients are lost too. Whole grains reduce the risk of cancer, heart disease, stroke and diabetes. The current recommendation is to eat at least half of your grains as whole grains, or at least three servings daily, yet only 4 percent of our nation is hitting this target. One serving equals 16 grams of whole grain.

Fiber refers to the non-digestible part of plant foods, like the bran in wheat or pectin in apples. Fiber helps to keep your digestive system clean by providing bulk to promote normal bowel movements. Certain fibers also help to keep your blood cholesterol low by blocking the absorption of cholesterol from foods. This type of fiber, called insoluble, is found in oatmeal, legumes and fruits. Aim for 25-35 grams of total fiber daily with 5-10 grams from soluble fiber. Look for fiber on a food label in two ways: the total gram amount per serving or as a percent of the daily value, or DV. At least 20 percent of the daily value is a good source of fiber - that's 5 grams. Soluble fiber is not required on a food label but in some foods with at least a gram, you can find it listed directly under "total dietary fiber.''

Sometimes a product will be made with refined grains and fiber has been added. For example, Arnold Natural Health Nut bread has 3 grams of fiber but contains only 8 grams of whole grain. Almost half of the grain is refined, and wheat bran is added to boost the fiber. However, Arnold does offer breads with a full serving of whole grain, such as their Natural 100 Percent Whole Wheat bread (17 grams whole grain and 3 grams fiber). Look for the wording "100 percent whole grain'' on a food label, which guarantees all of the grains are whole grain and the product contains at least a full serving (16 grams).

Some foods have a small whole grain "stamp,'' indicating the gram amount, for comparison shopping. For example, Kashi Go Lean and Kashi Go Lean Crunch have approximately the same amount of fiber - 10 and 8 grams - but the Go Lean Crunch offers more whole grain, at 13 grams. Or you could go for the gold with Kashi Autumn Wheat with 6 grams of fiber and 50 grams of whole grain per serving. The bottom line: Whole grain trumps fiber on a food label but you can get both with careful shopping.

Joan Endyke is a registered dietitian with a master's degree in nutrition and food science, and also a certified personal trainer. She is the nutrition director at Fitness Unlimited.

Readers may send questions about nutrition to Endyke at Fitness Unlimited, 364 Granite Ave., Milton, MA 02186 or by e-mail to jendyke@fitnessunlimited.com.

The information in this column is not intended to diagnose individual conditions. Readers should see their doctors about specific problems.