How? Pacman eats forever while Kirby is eventually full. It's not even a close contest.

Kirby swallows one thing and keeps it in his mouth.
Pacman just keeps going.

Pacman wins.

Kirby has a Black hole as a stomack. He can literally eat everything. Watch Kirby vs Buu Death Battle and see that this is not even a challenge.

Come on guy/gals, research.

Pac man wins.

Pac man doesn't stop eating, ever.

Really? I mean come on, Kirby guys please. Pacman does not keep eating...hence his multiple outings in different games. Ever played Pacman 2? He doesn't eat often in that game...at all. And when he does eat, he eats a piece of fruit or something or a little yellow ball, not an entire tree etc. Besides...kirby's gut is a bottomless black hole... Then again, I hate comparisons like this because their creators could easily come out and say "character X can eat more than character Y" and then what? I think these kinds of comparisons are only fair within the same canon universe.

Pac-Man, as he actually keeps what he eats inside, instead of regurgitating it like that fraud Kirby.

Kirby wins!
https://youtu.be/hLI8zuqfHVM?t=7s

Based solely on Triple Deluxe, Kirby. He sucks up pretty much everything in that game, no matter the size.

Kirby may eat faster or has bigger pieces at once, but Pac-Man is never full so Pac-Man.

As some have said already, Pac-Man never stops eating...it would take him some time, but eventually he'd be able to consume all of the multiverse.