Myth: Whole grains are always healthier than refined grains.

Reality: Whole grains are a healthy choice, but you needn't ditch refined grains. "You can have some of each," Rosenbloom says.

The U.S. Department of Agriculture's "My Pyramid" dietary guidelines recommend getting at least half of your grain servings from whole grains.

"It doesn't say you have to replace all of your breads with whole grains or all of your foods with whole grains," Rosenbloom says. She adds that enriched grains -- refined grains with certain nutrients added (such as wheat enriched with folic acid, an important nutrient for preventing neural tube birth defects) -- have some perks.

"Enriched grains generally are going to have more folate, thiamin, riboflavin, niacin, and iron. The whole grains usually have more fiber, vitamin e, selenium, zinc, potassium -- so there's kind of a trade-off," Rosenbloom says.