My oldest cat is obese. She was a rescue (as were my other cats), and was recovering from starvation when we adopted her.
Ever since, she's had food issues.
She gets noticeably stressed whenever her food dish gets empty, even if she's just eaten. On occasion, she'll respond to an empty food dish by overeating upon the next feeding, to the point she'll vomit.
We give her a spoon full of canned food mixed in with some diet dry food (only the dry food is diet; most of my cats will boycott the food if we try diet canned food) in the morning. We also fill the two cat food bowls with diet dry food each morning.
We tried limiting the amount of dry food left out during the day/overnight, but the problem is our other cats.
One of them is very timid, particularly when it comes to food. He is easily scared away from his food, and he generally skirts being underweight. If we restrict the amount of food left out, we're concerned that he won't get enough to eat. He won't even come into the kitchen to feed with the other cats, and instead is fed under a chair in the living room. Two of our cats are food aggressive, chasing him from his food so they can eat it.
How can we help our overweight cat lose weight? We've tried playing with her more, to keep her active, but it hasn't seemed to make a difference.