The Human Body is an amazing collection of synergistic entities controlled by what can only be described as Innate Intelligence. When something in the body is not functioning as intended by its designer, the body exhibits symptoms relative to the problem. Conventional medicine often takes a "symptomatic" approach and prescribes a pill or drug to alleviate the symptoms. Sometimes this well intentioned but a lack of knowledge approach causes unintended side affects that may be worse than the original problem.
Disease or "dis-ease" is defined as a lack of health. Disease results when any cell is not performing 100% of its designated duty, whether due to trauma, toxic reaction, lack of communication, or a combination thereof. Disease is due to stress and attitude. If you inflict stress upon your body/mind continually, and your menu is mostly cooked and processed food, then your body will not have the energy to repair itself, and will AGE faster.
Disease is nothing more than the body responding to the wrong we have done to it. It is the body's attempt at keeping us alive despite the damage we have inflicted upon it.