Are we really going to talk about what does or does not feels realistic
If it was the only reason, then sure. That said an RPG, a story driven medium, should probably care more about things making sense, then let's say: DOOM. And with the world like DnD we already have something as convenient as magic to cover for "gamey" stuff - like healing potions, resurrect and spells, which make for some of the most fun interactions mechanically, but are unrealistic. Food - however - I am not aware of food in DnD having a magical properties of healing people. And fiction hangs on internal consistency. Food healing both fails from narrative perspective, and theming perspective (food isn't the most intuative explanation for items that restore HP). And there is alreay in-universe items that provide their functionality - healing potions. So what's the point of food providing healing?
Larian makes short rest too weak? Sure. There should be more healing potions to buy. Sure. What's the point of making food into healing potions?
