I have personally NEVER activated last meal because I never see a need to do it, but just out of curiosity i decided to activate it for fun just to see what would happen.
It took a dragon fruit I had in my inventory, and in exchange I got half a heart.
I'm sure you can already guess what I'm about to ask for.
-# (also if it doesn't already make it interact with things like durian husk, lobster bib, and exotic spice okay thanks)