one fat kitten/cat, one skinny

(I posted this on the Health & Nutrition board, but I thought I'd post it here, too...)

hi, all.

I have two 8-month-old kittens who are still growing.

One is FAT and one is thin. They are litter mates and play all day.

The thin one eats until he's satisfied and walks away. They have their own bowls. The other cat will eat his food AND finish off the thin cat's food. I can't always be around to monitor, so I don't know how much each cat is eating.

They are still on kitten food. my vet suggested putting them on regular cat food when they are nine months, instead of a year. he said the kitten food is high in calories. he also suggested I give them a little less than the low end of what the kitten chow feeding directions recommend.

the vet said it's common for people who have two cats -- one will be fat, the other thin.

does anyone have any advice for me in feeding my cats, so that I can get one to lose weight without starving the other?

thanks!

I also have litter mates...one thin and one that looks like he swallowed a pumpkin. I think its a matter of dominance. Frantic (my thin cat) gets fed first. He also chooses which bowl he is going to eat out of. He'll often push Pipsqueek away from his food to take over the bowl. Pipsqueek asserts his attempt at dominance by eating what Frantic leaves.

I make sure to take up what isn't eaten after dinner. I divide the amount of food they should be having into a few meals. They don't get more than that.