>>213059227
This MCU Galactus doesnt seem to be able to change sizes at all. Not once in the movie is he shown drastically growing or shrinking. Happy to be proven wrong though. He just happens to be the size of a human skyscraper. He also doesnt eat planets, he uses his big spaceship to ram into it and smash up all the pieces into lava that get fed to him into the tubes on his back.