How to Help a Fat Cat Lose Weight

Simple steps to help your overweight or obese cat lose weight.

Portrait of a beautiful but obese calico cat
Photo: Thy Le/Shutterstock

By Zazie Todd, PhD

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If you have any concerns about your cat's weight or diet, or simply want to know if your cat is a healthy weight, speak to your veterinarian.

Many cats are overweight or obese. A review by Kathryn Michel and Margie Scherk, published in the Journal of  Feline Medicine and Surgery, summarizes the problem and the steps that should be taken to help cats lose weight.

Their paper begins by discussing the serious health concerns caused by overweight and obesity: an obese cat is almost four times as likely to get diabetes as a normal-weight cat, and more likely to suffer from other problems such as urinary tract disease and lameness.

They point out that just ten extra pieces of kibble a day, over and above what the cat needs, will cause a 12% increase in weight over the course of a year.

How much should a cat weigh?

Many owners are not very good at recognizing that their cats are overweight. A typical cat should weigh about 4.5kg (10 pounds).

Michel and Scherk adapt figures from the Association for Pet Obesity Prevention that scale up cat weight gain to human dimensions. For example, a cat that weighs 6.8kg – about 50% more than it should – is equivalent to a weight of 98.9kg (218lbs) for a 5’4” woman, or 115.2kg (254lbs) for a 5’9”man.

What to do if your cat is overweight or obese. Photo shows an obese cat looking at the camera
Photo: Kletr/Shutterstock/Zazie Todd

Apart from using accurate scales, you should also look at the shape of your cat. The waistline should be visible, as should a tummy-tuck, and you should be able to feel the cat’s ribs. 
So what should you do if your cat is overweight and obese? Portion control is obviously part of the solution.

Portion Control for Overweight and Obese Cats

A cat that is a little overweight should have a fixed amount of regular food, while very overweight and obese cats should be fed a special weight-loss diet to ensure they still get enough nutrients. Ask your vet for advice.

Many people use approximate measures for food, and an accurate cup measure, or weighing the food, would be better. When scientists asked dog owners to measure out portions of kibble using either a 1-cup food measure, a 2-cup food scoop, or a 2-cup liquid jug, they found the resulting amounts of food varied dramatically from too little to too much (Coe et al 2019). As well, although 1 in 5 of the participants had a weigh scale at home that they used for their own food, only 1 in 50 used it to measure out dog food. However, after having seen the errors in their measurements, most said they would be likely to use a scale in future.

Since cats eat smaller amounts of food than most dogs, they are more likely to be affected by inaccurate measures of food. Using a scoop or cup measure that is the right size for the portion they need, rather than one that's too big, will help with accuracy. But weighing their food using a scale is the best way to measure out the cat's food.

Keeping a food diary of everything the cat eats will help you stick to your plan. Remember to include products designed for dental health, as they also have calories.

Michel and Scherk say you can continue to give your cat treats, since it makes the cat happy, but should reduce the amount of kibble to take account of calories from treats.

"Just ten extra pieces of kibble a day, over and above what the cat needs, will cause a 12% increase in weight over the course of a year."

Don't Give Up Trying to Help Your Cat

To lose weight, a cat needs around 60-70% of the calories that it would need to maintain its weight. A substantial weight loss that does not reach normal weight will still have health benefits, so owners of very obese cats should not feel disheartened – they can still make a difference.  
It can help to know that weight loss may plateau after a while (AAHA 2014). This is normal and does not mean that you are failing.

If you are struggling to help your cat lose weight, speak to your veterinarian to get some ideas to help. And remember to celebrate the small successes along the way.

How to Feed Your Cat

Michel and Scherk also point out other steps that have been found to make a difference to weight loss, such as feeding via devices that require the cat to do some work: food puzzle toys for cats.

There are several containers on the market with holes in, designed for just this purpose, or you could make your own using a plastic drink bottle. My favourites include the Egg-Cersizer, the Catit Digger, and the Trixie Activity Fun Board.

Cardboard tubes – such as from toilet roll – can be fastened together, and food placed inside so the cat has to reach its paw in.

Another great suggestion is to put portions of the cat’s daily food on a small plate or in a cupcake case and hide it around the house, so the cat has to hunt for some of their food.
A beautiful Ragdoll cat playing with a toy
Engaging in play with your cat will help him or her maintain a healthy weight. Photo: Tony Campbell/Shutterstock

These ideas count as environmental enrichment for the cat, and other enrichment activities will help to increase the cat’s exercise.

Guidelines from the American Association of Feline Practitioners make several recommendations for feeding cats, which apply to cats of normal weight as well as cats that are overweight or obese. The recommendations on how to feed cats include providing cats with frequent, small meals, using food toys, and keeping food and water separate.

Exercise and Enrichment for Cats

For example, playing an interactive game with your cat, such as getting it to chase a toy or laser light (they suggest always ending by putting the light on a toy, so the cat gets to catch something and doesn’t feel frustrated).

Cats can also be encouraged to use a treadmill, or taken for walks wearing a leash and harness, such as this cat harness.

Consider the Human-Animal Bond

There is some evidence that owners of overweight cats have a tendency to over-humanize them. This comes from a study of 120 cat owners by Kienzle and Bergler (2006) in Germany. This study looked at cats that were not free-roaming (i.e. indoors-only or with access to an enclosed balcony/garden). Normal weight was defined as a queen under 4kg or a tom under 5kg, and overweight as over 5kg or 6kg respectively.

Owners of overweight cats had a closer relationship with their cat, and were more likely to say the cat consoled and encouraged them. They were also more likely to say their cat was like a child to them. While both sets of owners talked to their cats, owners of overweight cats were more likely to talk to their cat, and to talk about topics relating to friends and family or work.

Owners of overweight cats were more likely to watch their cats eat, suggesting that food played a greater role in their relationship. Owners of normal-weight cats were more likely to play with their cat.

Michel and Scherk conclude that it is important to consider the cat caregiver when discussing a cat weight loss program.

They say,
“The value of encouraging alternative ‘strokes’ – things that make the person feel good about their interaction with the cat, such as play and a sense of pride in achieving weight loss goals – is not to be underestimated. Positive feedback, both from the veterinary team (the outside environment) as well as self-generated by the client, is vital to the success of a weight loss program.”


Monitor Your Cat's Weight

Michel and Scherk's excellent paper is aimed at vets, but it contains many ideas to help the average pet-owner. Speak to your veterinarian if you have any concerns about your cat's weight or diet, or if you need advice on how to help your cat lose weight.

Do you keep an eye on your cat’s weight? And, do you have any tips for feline weight loss.

If you liked this post, check out my book Purr: The Science of Making Your Cat Happy. Modern Cat magazine calls it "a must-have guide to improving your cat's life."

Zazie Todd, PhD, is the award-winning author of Wag: The Science of Making Your Dog Happy and Purr: The Science of Making Your Cat Happy. She is the creator of the popular blog, Companion Animal Psychology, and also has a column at Psychology Today. Todd lives in Maple Ridge, BC, with her husband, one dog, and two cats. 

Brooks, D., Churchill, J., Fein, K., Linder, D., Michel, K. E., Tudor, K., ... & Witzel, A. (2014). 2014 AAHA weight management guidelines for dogs and cats. Journal of the American Animal Hospital Association, 50(1), 1-11.
Coe, J. B., Rankovic, A., Edwards, T. R., & Parr, J. M. (2019). Dog owner's accuracy measuring different volumes of dry dog food using three different measuring devices. Veterinary Record, 185(19), 599-599.
Kienzle, E., & Bergler, R. (2006). Human-animal relationship of owners of normal and overweight cats. The Journal of nutrition, 136(7), 1947S-1950S.
Michel, K., & Scherk, M. (2012). From problem to success: feline weight loss programs that work. Journal of Feline Medicine and Surgery, 14(5), 327-336.

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