One cat eats too much and the other eats too little

by Zeze
(Washington Country)

Of my family's two cats, one eats too much and the other eats too little. She has been losing weight and she was at an ideal weight. What should I do?

They both eat from the same bowl. They eat special cat food because the greedy one pees outside the box - due to anxiety - and is very picky about the litter box. The smaller one likes to chew on plastic and while reading up on that I found it could be related to anxiety.

Last week the small one threw up. I am not really familiar with cat throw up. It was dark and rolled loaf-shaped and the color of her fur.

We have been trying to reduce the large one's food intake under vet's orders so they get 1 cup of cat dry food a day with treats every once in a while throughout the week. These past few days, I have been trying to feed the smaller one separately in a larger quantity than she would normally get.