Ask five nutritionists to rate the 13 most powerful foods and you'll get five different lists, but many of the selections will overlap. Why? Because every food provides something different: Some are a rich source of protein or fiber but void of many vitamins and minerals, while others contain disease-fighting phytonutrients, vitamins and minerals, but no protein. The trick, claim experts, is to get a variety of the best foods. The following 13 power foods are a good place to start.