It's cooked meat, bread, raw vegetables and berries, the same food i have/had all the time. And I'm in the same area, where I have been playing since some weeks (some kind of woodlands/meadows). It just started with the update to version 1.12.11.
I'm using no mods (ok survival is a "mod", but that's all) and I changed food spoilage speed to 50% and hunger rate to 75% (directly in the beginning in the process of world creation).
Even when i was just standing in my house with full health, full saturation bar and doing nothing, the saturation bar was running down extremely fast.
For the moment I went back to v1.12.8 where those problems didn't exist, because updating to 1.12.9 already killed about half of my food, preserved in clay jugs in a cellar (food that was good for several weeks before updating).
(unfortunately that version 1.12.8 has the problem, that the game process often "dies" in pause mode which i use, when I am afk for a while).