Grandma meant well but followed the m.d.s

 she lived until almost 92

mistakes she unknowingly made 

not eating real butter, using fleishman's margarine instead

using saccharine, artificial sweeteners especially in her coffee, which was decaf, another huge mistake in using.. sanka 

taking prescription meds for migraine headaches (caffergot) because she did not know what was causing the headaches and the doctors of course would not tell her ..they want the money from the patient and made even more money prescribing drugs