Albert Einstein, the great scientist, stated that energy can become matter and matter can become energy. The physical food that we eat is the matter that becomes energy thanks to the digestive system. Ancient wisdom says: "YOU ARE WHAT YOU EAT!" This is so true because the food we eat becomes energy and we are energy. The energy taken from our food becomes part of the energy we are. Nutrition takes a huge importance when we know that the food we eat become part, as energy, of us. Now it is so easy to understand that eating junk food, that many people love, is not the best idea because it is not the best energy to eat.