It might take patience to get the best benefit from the SlimCat but it is worth it. When the ball was new, my cat did not want to have to push it around. He would just sit and look at it until I would take his paw and give the ball a knock until kibble would fall out while saying 'push'. (He has since learned the word 'push'). My cat receives a measured daily ration to keep his lovely figure. A small portion he gets as breakfast, a small portion is reserved for bedtime snack and the rest goes in this ball. First thing in the morning I make the holes just big enough that when I shake the ball one or two falls out. By evening if there is still a lot left, I will make the holes bigger (that's probably the best feature of the SlimCat). On the days when he seems like he wants to eat all day, I make sure the holes are small enough that he really has to work to get some kibble. He doesn't always LIKE pushing it around now, but he knows that is how he gets his food through the day and it does serve as an activity for a cat with few mice to catch.
This is a great tool in preventing obesity. It holds about what an adult cat should eat in a day. My veterinarian actually has noticed more muscle mass from Scooter's daily pushing. The only downside is the locking mechanism that adjusts the size of the whole eventually slips, and then it's time for a new SlimCat. But for the price, and how it keeps my cat from obesity and all the related health issues, that's a very minor issue.