i know your situation, kinda..when i was just 14-15 years old, which wasnt that long ago btw, i also discovered that somewhat "sad" truth about food, that we just cant eat whatever we want if we want to be healthy, fit etc, after some years, which is now i almost completely understand all rules about eating and when i try to tell that my parents, and especially grandparents, for their sake, so that they start to rearrange their eating habbits and could get rid of their health problems and live longer, they just try to bug me off like if what i say is nuisance, i know that it is actually, but i just dont understand how grown up adults can be so ignorant, recless and well even more childish than i am supposed to be at my young age, i just dont know how to make them accept this truth, i know i should let them be free about their choice, but at the same time i cant because i know that what they will chose wont be right, so what to do? i want my grandparents live long and healthy, but they just dont want to bother about anything, just enjoy their food :(