My cat also knows a few tricks. A few years back, he had fatty liver disease, which is caused by a vicious cycle where the cat won't eat, which makes them sick

My cat also knows a few tricks. A few years back, he had fatty liver disease, which is caused by a vicious cycle where the cat won't eat, which makes them sick and suppresses their appetite. The first thing you try when this happens is to jump start their appetite by encouraging them to eat however you can. Ultimately, I couldn't get enough calories in him, and we had to do a feeding tube. But before that, I was able to get him to eat some treats. He wouldn't eat them if I just gave them to him, but if I had him do "shake" first (the only trick he was up to), and then gave the treats as a reward, he would eat them. I found it fascinating that the reward had taken on its own meaning for him. You might naively model training with rewards as "the cat is hungry and knows that treats bring food". But he didn't want food. After years of practicing tricks, it's like being rewarded became its own positive experience for him, and the ritual of eating the treat is part of that experience, independent of whether or not he actually wants to eat.