most of life... naturally"
Without energy life cannot exist. Every function, every action, every thought depends on energy. If you remember from your school days, the law of energy maintains that energy can be neither created nor destroyed, it can only change form. All of the energy released in our cells comes from the foods we eat, and that energy comes from the radiant energy of sunlight, trapped by the plants around us as they transform carbon dioxide and water into carbohydrates and oxygen.
Not surprisingly, the release of energy from food is a complex biochemical process, requiring a myriad of essential vitamins and minerals, a functional deficiency of any one of them can result in a lowered energy state, better known to us as fatigue.
Fatigue is the most common symptom patients present with to their doctor, but more than 90% of the time the fatigue is not the result of a disease process but a functional disturbance. In other words, at least 90% of the time fatigue can only be helped by changes to your diet, to your lifestyle, or with supplementation of therapeutic nutrition.