Why is my cat eating too much and misbehaving?

got 2 brother kittens, after 3 days one ballooned in size compared to the other, he just wont stop eating, its gotten so bad he tries to go through the garbage and jumps on the furniture (to snatch food off of plates) what can i do to stop this? we're spraying them with water but it doesnt seem to be that effective. any other remedies/repellants? he eats all of his catfood THEN our food as well. we give them plenty of attention as well so it isnt like they arent cared for... any advice?