@Psychronia
You know, something had occurred to me while I was rereading this. Could Garius's figure despite being a Hero be because he's inadvertently "fully using" any food he consumes?
That's a really interesting train of thought. What, exactly, is considered an "item" by his power? We know that the fish counts to a degree, as he explicitly mentioned it when he tossed it to Lippi a few chapters back, so it's entirely possible that food counts as an item, so his body would thus make full use of it and absorb everything; he'd probably be incapable of exercising enough to counteract the caloric intake of even just standard meals. You could compound this with the likelihood that his body itself isn't considered an "item" for the sake of his power, meaning said exercise would probably be several times more difficult.
On a somewhat hilarious, if also gross, side note, if his body
does fully use the food he eats, it's entirely likely that he doesn't actually poop, since there's nothing wasted for his body to expel.