When it comes to dieting, people tend to go to extremes, says Dr. Donald Hensrud, director of the Mayo Clinic Healthy Living Program. And that's true for carbs. Carbohydrates are vital for good overall health. And eating them doesn't need to be complicated, but they should be whole and complex.

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"There are a lot of carbohydrates in the food supply. Many of them are not that healthy," says Dr. Hensrud. White bread, for example, is a less healthful option than whole-grain bread because of how it's processed. "We take out the fiber, the bran, and we take out the germ. These two parts of the grain contain most of the nutrients. We add back some of the nutrients, thiamine, riboflavin, but we don’t add them in the correct amounts that are present in normal whole grains."

Many processed foods contain added sugars. "Sugar intake has increased tremendously in this country, and added sugars are a big health problem." Dr. Hensrud says change out sugary snacks with fresh fruit, and, instead of processed white flour, try whole grains. "Whole grains, such as brown rice, oatmeal, quinoa, and some of the ancient grains—whole-wheat pasta, whole-grain bread—those are wonderful foods. And, consumed in moderation, they can improve health."