Those foods that are in there original form. Unprocessed, organic, and unchanged. There is no one food that comes to mind, we need all nutrients, that come from many different sources. Protein, to build muscle, and for the amino acids. Which are involved in countless bodily functions. Omega fatty acids, for brain health, joints, and nerves. Fruits, and vegetables, for Vitamins A, C, and carotenoids, a co factor in the utilization of other nutrients, and substances. Whole grains, for vitamin E, and necessary trace minerals.
To say there is a perfect food it does not exist. We require a balanced diet to maintain good Health.