For all we know, a 12/12 could be better than 16/8 anyways. I sometimes do a sort of 12/12 where one of the meals is basically all fat (heavy cream for ice cream), I won't call it bulletproof icecream, but I guess it's the same general idea, I think probably separating most of the carbohydrate (not that there's much for me) and protein from the day's fast makes for lower insulin over all. If you look at the insulin index, fattier protein foods make for less insulin per calorie--but more insulin per gram of protein.