Is it more important to eat healthy foods or low-calorie foods?

Both factors are important. Beware of packaged foods that say "low calorie," and opt for whole foods instead. Processed foods can contain tons of salt, refined sugar, and fat, even if they are low in calories. A better choice is always whole foods--fruits, vegetables, whole grains, and lean proteins.

While you need to eat a variety of healthy foods, also remember that even nutritious foods can have high calorie counts. For example, a watery vegetable like a cucumber (one cuke has 16 calories per cup) has fewer calories than the same-size serving of cooked brown rice (216 calories). Both foods are great sources of vital nutrients like vitamins and minerals, but you should keep an eye on portion sizes of the foods that have more calories, like brown rice.

The best nutrition comes from eating a balanced diet of whole foods.

Source: Dr. Pamela Peeke, MD, MPH, is a member of Prevention's advisory board and the author of Body for Life for Women (Rodale Inc.).