I have an almost eight year old cat who weighs over 20 lbs. We recently brought him to the vet to get his shots updated and of course the vet suggested that we try to get him to lose weight. He's been on weight loss food measured out for a while but getting him to exercise is a struggle. I got one of the food dispenser balls and tried for the first time today. I know he knows the food is there and he should eat if he gets hungry enough but he's barely eaten all day and thrown up phlem a couple times, which he does for some reason when hungry. I don't know how long I should hold out before just feeding him normally and trying again with the ball later. Anyone else have experience with this? I know I'm to blame for how big he's gotten but I love him so much and want him around as long as possible.