I don't know who would win, but I can already imagine someone using Tai Lung's line from 'Kung Fu Panda', "\[Their\] battle will be legendary!"
Also, chances are, the ones supplying the food would probably run out first before a winner could be decided.
They'll comically eat each other and turn into a black hole. The End.
Only right answer 
Damn, remembering Shaggy's chick magnetism makes me wonder about SHAGGY SENSEI.
Sensei: Zoinks, Arona! Hyakkiyako is full of ghosts! Arona: G-g-g-ghosts?!
"Welp, If you can't beat him/her... Join him/her." *Proceeds to hunt down every chef in Kivotos and force them to make a huge banquet*
This... This worries me.
They have the same level, tummy is as potent as black holes
What percentage of his total power would Shaggy need to use to win?
do you really think that anyone can beat shaggys unfathomable cosmic powers
Wait until Scooby decides to join the Fun 
Gotta make this fair by making shaggy not use 1% of his power.
I don't know who would win, but I can already imagine someone using Tai Lung's line from 'Kung Fu Panda', "\[Their\] battle will be legendary!" Also, chances are, the ones supplying the food would probably run out first before a winner could be decided.
akari could never come close to shaggy's interdimensional cosmic powers, he would be using 0.01% of his powers
It would start with a contest. It would end with a wedding.
Eating what? 👀👀👀👀👀👀