What causes weight gain in cats?

Most of us are familiar with watching our waistlines and know how easy it is for a few minor indulgences to make big changes on the scales! This can just as easily happen to our cats, especially when giving food is one of the things that makes the bond between animals and humans so strong. With weight changing gradually, it’s easy for even the most well cared-for cat to become overweight or even obese without us noticing.

As well as the obvious causes – too much food, too little exercise, and excessive snacking – there can be other contributing factors to weight gain in cats:

• As cats age, they tend to become less active and therefore need fewer calories to maintain their weight. 
• The process of neutering or spaying alters the metabolism of cats, making them prone to weight gain.
• Occasionally, weight gain is associated with specific medical conditions that require treatment.
• Environmental influences can affect a cat’s weight. For example, your cat might be apprehensive about going out if you move to a new area, or may become reclusive if there’s a new pet or baby in the house, leading to less energy expenditure.

Signs your cat may be gaining weight

There are a number of ways you can tell if your cat is carrying excess weight:

• Tightening of the collar. 
• Slow movement.
• Difficulty in walking.
• Shortness of breath.
• Sleeping more than usual.

If you notice any of these signs, it’s time for a trip to your vet. Even better, you can get ahead of the game by weighing your cat on a regular basis. 

When your cat was a kitten, your vet will likely have tracked their weight as they grew into adulthood. After neutering, though, it’s not uncommon for cats to only visit the vet clinic once a year for their annual check-up. A lot can change in that time!

It’s a great idea to get into the habit of weighing your cat regularly. Most vets are happy for you to pop into the clinic for a free weight check. However, if your cat doesn’t like travelling to the clinic, you can do it at home using your own bathroom scales. If your cat is a chilled-out moggie, you can place them directly on the scales. Alternatively, weigh them in their basket and then weigh the basket separately, then subtract the weight of the basket to get the cat’s weight.

Getting into the habit of doing this every month is really useful. You’ll spot trends up and down, both of which can be very early signs of either simple weight gain or other diseases. If you can nip weight gain in the bud early on, it’s much easier to tackle and the risk of associated health conditions is lower. 

If you’re at all concerned about your cat’s weight, see your vet. They can recommend a lower-calorie food or something more suited to your cat’s lifestyle and age, and they can check for any underlying health problems that may need attention. If there’s a medical reason for your cat’s weight change, the sooner you can start treatment, the better. Your vet will never judge you for asking questions and being safe rather than sorry.

Reviewed by Dr. Hein Meyer, DVM, PhD, Dipl-ECVIM-CA and Dr. Emma Milne BVSc FRCVS