[quote=Charm2017]Susanne

Ah, you rephrased my question so much better than my convoluted approach. I brought this up in the general forum rather than the sub-forum with diet & exercise therapies because while I am familiar with their posts, my question was triggered by the rash of books and articles on how diet or nutrition can prevent cancer. Yet, if the caregiver, the eventual cancer patient, and the rest of the non cancer family all had the same meals, indeed as you restated the question, why didn't they also get cancer?
I am openly skeptical based on my personal experience about the generalities of diet and cancer as applied to head and neck cancer. HPV & environmental issues seem more likely culprits. While I can't be sure why I got cancer twice, I am getting very tired of reading it is because of what I ate or did not eat. Whoops, got to watch my tone or else post this in the 'coping anger forum" under my "don'tcha hate it when" thread. [/quote]

I'm not one to place a great deal of stock in unproven diet claims however, to answer your question, I think the reason people who eat the same diet may have different health outcomes is for the same reason people who smoke cigarettes have different health outcomes.