Diversity helps ensure you obtain all the nutrients you need and helps you avoid too much of any one contaminant. There are probably other reasons we do not understand, but no matter what the mechanism, choosing a diverse diet can make your RealAge (physiologic age) younger. If you eat from all five food groups daily, you can be as much as five years younger than if you ate from only two. (The five groups are breads and cereals; fruits; vegetables; low-fat dairy products or dairy substitutes; and meats, poultry, fish, nuts, and other proteins.) It is also important not just to choose one thing from each food group but to eat diversely within each food group. For example, some vegetables contain lots of one nutrient and virtually none of another. Try to eat four servings of fruit, five servings of vegetables, and two to six servings of whole grain breads, cereals, or other whole grains a day. These amounts will give you the vitamins and fiber you need without excess calories. Eat one to three servings of low-fat dairy foods or dairy substitutes and a serving or two of protein-nuts, beans, meats, fish, or poultry-daily.
More Answers from Michael Roizen, MD