I have been trying to build up a small stockpile of more valuable food typed before I send a group out on a longer expedition. Got plenty of dried meat, in a food barrel. But as soon as I put some more nourishing in a generic container (not food barrel) all the characters take that instead.
Is there anyway to forbid some food types or containers?

there is not

Well I found a work around. Put my ration in the research bench, and none of my chatterers took them.