When I first start the game, I get thirsty and hungry as normal and have to drink and eat. When called away (or doing laundry), I exit to the main menu and leave the game in that state until I return.
Re-entering testlive in single-player (no mods), I do not need food or drink and my thirst and hunger indicator both remain at 100%. Upon taking damage, I still need to eat to regenerate health, but not to sate my hunger.
At least for my particular setup, this is repeatable and has happened 5 days in a row, several times each day. That’s when I first noticed it.