Well... the Elf's flesh eating ability... Is a massive heal (stronger than basically any healing spell in the game) and it offers massive continuous healing... AND it creates a blood surface... AND you can find tons of bodyparts.
So... I guess having endless access to super healing potions for free isn't an great advantage.
Elf flesh-eating is a racial trait not a foodstuff. Try feeding flesh to buddy or eating it as a human.
In any case eating flesh doesn't create a blood surface - only Flesh-Sacrifice sacrifice does and that doesn't require any body parts at all.
Nor is it flesh eating the strongest healing in the game as Healing Elixir (Yarrow + potion) is 80%.
The question was about foodstuffs. Not the same.
Foodstuffs (which anyone can eat to get a bonus) are weak. So are potions - I've only used wits potion to get the tyrants trousers. Otherwise they are mostly pointless at the moment.