My cat is losing weight

Written by Sjoerd | May 12, 2025

Is your cat losing weight? This is something we often see, especially in older cats. There are several possible causes, and in this article, we’ll explore the most common ones.

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Why is my cat getting thinner?

If your cat is losing weight, it’s important to identify the cause. Weight loss in young cats is not normal. While it’s often attributed to ageing in older cats, it should never be overlooked — weight loss is not a natural part of ageing.

There are generally three reasons why a cat may lose weight:

Your cat eats less and therefore absorbs less energy.
Your cat burns more energy than it gets from food.
Your cat is losing energy in an abnormal way.

My senior cat is getting thinner

Even in older cats, weight loss should not be considered normal. While older cats are more at risk for conditions like kidney disease or hyperthyroidism, another common cause is often overlooked: arthritis.

Arthritis reduces a cat’s mobility and leads to muscle loss. You may notice that their body shape is normal, but the muscles in the hind legs appear wasted. Some cats can even be overweight and still suffer muscle loss, which only worsens the arthritis. Learn more about obesity in cats.

Arthritis in cats is often underestimated but can significantly impact their quality of life. Signs include avoiding jumping onto counters or beds, sleeping more, or no longer climbing stairs. If you notice these behaviours, have your cat examined by a vet.

With proper dietary and joint support, arthritis in cats can be managed successfully.

When should I see a vet?

If your cat is losing weight and you don’t know why, consult your vet. As you’ve seen, there are many different possible causes — and no one-size-fits-all solution.

Monitor your cat closely. Measure food portions and note what’s left. Weigh your cat monthly to catch any changes early.

Still have questions about your cat’s weight loss? Feel free to contact us at [email protected].