I always hate this "as our ancestors did" crap because.... which ancestors? And how far back are you going? I came across this when an acquaintance had bone cancer and was on a macrobiotic diet. I looked into it, not for myself but just out of curiosity, and found out it was one of these ones that excluded nightshade plants. I know lots of diets apparently do that, but the reasons given when I was looking into it were that nightshade plants were New World plants and "our ancestors didn't eat those." I'm like ... ?? But??? People do eat them, did eat them, for thousands of years, in the New World.

I can see not eating something that your body reacts badly to (milk, if you're lactose intolerant; shrimp, if you're allergic to shellfish, etc.). That's it! This whole "our ancestors" thing--no.