Listening to Magic Pill and the author describes animal testing of effects of different foods on appetite. I can't help thinking of Ted Cat.
When Ted Cat came here I noticed he was quite short for a Nieb breed cat and he was ravenous. He would not stop eating. He would attack anyone who came near him. He only wanted packet food with gravy and would leave good food uneaten. He wanted to eat 3 times a day.
Over the months I slowly changed his diet. One packet food and some fresh food. He rejected good food and would get angry. I put out a huge bowl of crunchies to last for days, he ate it all in a day, his poor tummy was distended. He now eats fresh Fussy Cat meat and Fussy Cat kangaroo crunchies only. I now measure it all out carefully, I gave him a slow eating bowl so he wouldn't wolf it down then start on Bill's food. I fed him outdoors.
Then I got sick and husband fed the boys, they got unlimited food. Ted just went crazy and ate and ate, he's now on a diet and it's working.
The positive thing is that Ted Cat now eats healthier food , not packet food with gravy. I don't know if he would choose gravy if offered. That's the thing, Ted Cat doesn't need will power, he doesn't have the ability to make choices between foods, for him it's eat or have nothing