I would not try to force my cats to “lose” their excess fat. It helps maintain them in their elder years.
I may get a lot of slack for saying such a thing, but I highly doubt my Kitty would have lasted over 19 years if not for her “added” poundage.
If your cat is 20 lbs overweight and is diabetic then of course, he/she needs to be put on a diet to control the disease.
A few pounds over? Screw it. Let the kitties have it. Those few extra pounds help an elder kitten.
While at first read, you’re idea sounds horrible, however, I have noticed that when cats reach what I would assume is kitteh social security age, they start to lose weight dramatically.
I’ve seen it happen more than once and it’s almost impossible to get them back to their ‘normal’ weight.
I’d don’t know why it happens and if it has a detrimental effect but I would like to keep the elder kittehs well fed.