I just noticed recently in experimental (.50) that my character wasn't losing his energize buff (light green).

For a couple days now I stopped eating food of any kind. No change in the buff. (although I am still thirsty at a regular rate).

For an hour I ran around very hard letting my character wheeze for breath and lost my light green hydration buff; and still energize LIGHT GREEN.

My character was hungry in the beginning, it was the same kind of "les stroud" style survival that I am used to (and love!). So I am a little sad I don't need food anymore, its like half the game has been taken out.
[I am currently running the rest of my food over to cherno/elektro for freshies, something to do.]

EDIT:
Photos below show before and after for about an hour without touching any food.
(although I did drink)