Oooooh, darkest headcannon theory for doomguy
Big guy doesn't want to admit what he's had to do to just survive in Hell.
More so in early days, before his mortal body adjusted to absorbing energy to sustain himself. He won't ever admit to needing to hunt down as newly possessed as possible to be able to get any semblance of food before he was able to digest demon flesh or hellgrowth without the intense, burning, agony that comes with that.
He won't admit he had to learn in hell how to restrain a possessed to carve out meat and organs. Or how to learn to block out screaming that sounded just that little bit too human.
He'll let everyone think he just absorbed energy before he learned what hell's energy was, or those orbes of 'free' energy were.
There's good reason he treasures real food so much. Soft or cold more so. Same reason he can easily eat any kind of raw meat, even alien.
(Just let him have some root beer and macaroni and Cheese)