It seems the liquid path is very likely not working
I can't rule that out, I'm not that good at reverse-engineering code, especially object-oriented like this. I'd probably have to make a debug copy of the game and where I can spawn food and watch the variables. Also, this is from v0.1.00, which is not up-to-date anymore.
BTW there is more unused code, for example a mother character with another hunger meter
and a script for a short VN featuring a character named Elias, and it seems only the code of the dialog boxes was ported from that.