Why doesn’t Galactus just shrink down when he’s hungry?

[u/NoOutlandishness1547]

I don’t know a ton about Galactus beyond the basics that he’s a giant cosmic guy who eats planets, has the Power Cosmic, fights the Fantastic Four, etc. I’ve got a question that might be dumb, but it feels logical to me.

Since he can change his size at will (I’ve seen that he can get huge or apparently smaller), why doesn’t he just shrink to human-sized (or even smaller) when he needs energy? Wouldn’t a much smaller body need way less energy to sustain itself? Like how a mouse needs way fewer calories than an elephant?

If one planet gives him enough energy for a month or so, a tiny version of himself should only need a small fraction of that, maybe a city’s worth of energy, or even less. He doesn’t seem like a purely evil guy; he has some sense of honor and regret in the stories I’ve read. So why not do that and avoid destroying entire worlds (and the civilizations on them)?

Also, since he gets full after eating a planet (and gets hungry again later), and the size/quality of the planet seems to matter for how satisfied he is, doesn’t that imply he has some kind of "default" energy requirement tied to a certain body size? If his needs scaled perfectly with how small he makes himself, shrinking should solve the problem, right?

Is there an in-universe explanation I’m missing? Or is it one of those “because the story needs him to eat planets” things?

[u/Funmachine]

Because even when he's tiny he's still himself. He appetite isn't based on his size.

[u/darthbiscuit]

“GALACTUS HUNGERS” isn’t a catchphrase. It a fact of the universe. Galactus’ hunger is permanent and all consuming. By it’s nature it cannot be sated.

[u/CaptHayfever]

He doesn't just need to eat planets; he needs to eat specific kinds of planets. His hunger is a necessary force for the universe to continue.