Instead of feeding him ground meat, just feed him some meat chunks with no vegetables.
The meat chunks can be the size that he can easily swallow or slightly larger causing him to chew through the meat using his molars.
Always let your cat eat as much as he wants at every meal. In this way his body becomes nutritionally satiated. When his body is nutritionally satiated, then his body will reduce its food intake.
Cats and dogs have stomachs that are approximately 65% of their digestive system. So they can eat a large meal.
But what I would also do is this:
- Feed him some meat chunks — this allows him to eat more food faster than feeding ground meat.
- Put enough food onto the plate so he eats his food but make sure there is enough food added to the plate so after he walks away, there is still enough food for him to eat over the next hour, two or three — this way, he will walk back and eat some more food.
- While this seems like free feeding, it's not really. Free feeding is when he can eat at any time during the day. All we want to do is have enough food on the plate so he eats one large meal and then goes back for small amounts more over the next 2 or 3 hours. Many cats do this in nature — they kill their prey, eat a huge amount, then wait for some room in their stomach and then eat some more of their prey.
With meat chunks, it is difficult to add hot water to the meat and so instead, let the meat chunks sit on the counter top for about 1 hour to remove any chills from the meat — you may need to cover the meat so he doesn't eat it too soon!
But you may find that meat chunks will serve your cat better and adding enough food to the plate so he can eat over the next few hours will make a difference.
The major issue is that domesticated cats who are used to eating all the time are not always as fast to eat. This is because they know there will be food available every day. There is no urgency. But if you were feeding stray cats, then they will eat immediately, they will eat fast and they will eat until they can barely move — only because they are not used to have food every day.
I saw this behavior when I operated my cat sanctuary and even though I fed them every day, they still would eat as if it were their last meal — yet my domesticated cats would eat a good meal, but not with the same urgency.