system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] Why does Galactus need to feed while his Heralds don't need to?

I have been pondering this. Galactus infuses a Herald with the Power Cosmic, he needs to constantly feed but his Heralds can be fine for billions of years and are super powerful. Still below Galactus but still top tier.
gpt
Simple. Why do elephants eat more than rabbits. They are bigger.

The Heralds are sustained by the Power Cosmic, a powerful energy force in the universe. It also grants them great, but not unlimited, power. Galactus requires much greater sustanance, simply because he is a "larger" cosmic force, not in size but in power. He is one of the figurative cornerstones of the universe, and if he were to die or cease to exist, the universe normally would shortly end thereafter. While the Heralds can be sustained and empowered by absorbing background cosmic energy, Galactus requires the equivalent of one life sustaining planet per month to maintain his life energies. He requires a lot more energy to sustain him.