If you want to diet, just mix the dye in the sink and dip it in!

I would recommend probably not feeding just once a day. Maybe you should wean them down, too? That might be easier for you. They can get used to eating less gradually. If Eliot is hungry, you can shut him in a bedroom to eat for a while.

Pickles is getting a little plump, but I can't imagine trying to put him on a diet. If he gets down to a few morsels in his bowl (it doesn't even have to be empty) he goes crazy.

Good luck, and I commend you for having the patience to get your kitties healthy!