Reeper, the food doesn't change DNA, only adds muck to natural color. Like if humans were to eat a lot of carrots or tomatoes their skin turns orangish, but stop eating so many carrots and tomatoes the skin reverts back to normal color. (condition names are carotenemia and lycopenemia).
In the case of neos, I found astaxanthin causes color problems in neos, but eliminate the astaxanthin and the colors go back to normal...eventually.
I think a lot of people initially get excited over green appearing in neos, when actually it is the food fed. Green is only a stop between colors for yellow. Too much of that food and the yellows will eventually go brown.