Most modern dread diseases & syndromes, responsible for the majority of the ever more common, serious health challenges, have their roots in your choice of lifestyle. So does the epidemic of fatigue, which today is the single most common complaint, followed by aches & pains, a general lack of a sense of wellbeing and zest for life.
Your body is a fantastic machine, capable of near miraculous feats, but it can only perform at it's best, live long, strong and healthy, if fed the food it was designed around. Feed your body anything else or neglect physical activity and you will damage it. Keep doing it for long enough & the damage will be potentially irreversible, eventually possibly even deadly.