Slimming advice for your cat

Unsure why your overweight cat can't seem to shift the pounds? Vet Susan McKay offers some invaluable advice.

Reader's question: My four-year-old cat Reuben is obese, weighing in at 12kg. I put two bowls of dry food out (each bowl has about half a cup of food) then I split one can of wet food between all of my cats. I refresh the dry at night.

I don't notice Reuben eating any more than the others and I also play with him so he has some exercise. Can you suggest anything that might help him lose weight? He does have a much larger frame than my other cats.

Vet Susan McKay says: Well it certainly sounds as if Reuben is on the large side. An average cat weighs around 3.5kg to 4kg and although some have bigger frames, 12kg does sound like rather a lot.

He needs to be checked out by your vet just to ensure there are no other causes of his obesity. Although other causes are unlikely, I think this is worthwhile as you are not really feeding a lot of food.

Also a health check can reveal other diseases that can result from obesity, and that may affect how you feed your cat on an ongoing basis. All of that aside, I think the most likely thing is that your cat is overeating.

Once a male cat has been neutered it has been shown that they will increase their food intake, unless you regulate the food - so any ad-lib food that is available will be consumed in greater quantity. There will also be a drop in metabolic rate so neutered cats actually need less food than before, which adds to the problem. So Reuben is probably consuming more than his fair share of the dry food you leave out.

To get him down to his ideal weight, you need to feed 50 to 80 per cent of his calorie requirement at the ideal weight. For Reuben that's going to be a big calorie restriction and if you just do that by reducing his food, he may not get enough of the nutrients he needs.

That leaves you with the option of feeding a prescription-type diet that is restricted in calories but contains enough nutrition. He should also have veterinary supervision because if obese cats are too severely starved of calories they can develop a condition called hepatic lipidosis, which causes accumulation of fat in the liver and liver dysfunction.

I think you are going to have to revert all your cats to meal feeding, rather than ad-lib feeding, as otherwise Reuben is just going to scoff everybody else's food. There are various suggestions of ways you can still feed cats together when one is on a diet, ranging from feeding lean and active cats at a height and leaving the food of a less mobile, obese cat on the floor, to leaving your normal weight cats' food at the end of a tunnel or tube that the obese cat cannot get through. There are also microchip cat bowls and activity feeders available that would work well in this situation. Good luck!