My grandfather lived into his nineties, when he died in bed of pneumonia. He never went to a doctor or dentist in his life and he still had all his teeth when he died. Good food was his physician: three meals a day. He grew some vegetables and had a few raspberry and gooseberry bushes in the back garden, and he ate plenty of animal fat: none of this foolish modern practice of cutting off all visible fat from the meat on one's plate. My grandparents reached and passed their diamond wedding anniversary. Over 60 happy years together.
I believe that two of the major causes of ill-health today in the developed world are 1) the adverse side-effects of pharmaceutical drugs, which are wantonly over-prescribed, often in high dose, by a medical profession too influenced by drugs reps, too ill-informed about drug side-effects, and too little interested in the therapeutic possibilities of improved nutrition, and 2) the dire effects of processed foods, produced by a food industry intent on profits and to hell with the damage done to the physical, mental and emotional well-being of their customers.