FOR MOST PEOPLE, a balanced, whole-foods diet provides the key nutrients—proteins, carbohydrates, fats, vitamins, and minerals—that are essential for life and good health. If those nutrients were all that whole foods provided, most of us could thrive on junk food, as long as we took nutritional supplements. That is not, however, the case. While many individuals do benefit, sometimes dramatically, from nutritional supplements, individuals who also work on their diet achieve the best results.