Hunger can go into the negative, especially noticeable with contaminated produce at high infection levels. This is important because of MREs - MREs seem to subtract a set amount from hunger and then set your hunger to zero, giving a ration for every <x>% negative the number is.
When you're at like 120% infection, eating 2 or 3 contaminated produce and then eating an MRE can give 20-30 rations. Then you can reduce your infection with drugs and be able to survive a long time off of the newly gained rations. My highest amount obtained this way was getting the "Lick walls in underground base" event, then eating 8 contaminated produce to get 80 rations.