Cat has been losing weight the last few days

My cat has been losing weight the last few days. Does this happen a lot in spring?

My cat is 5 years old, a barn cat that stays INDOORS every night. I let them out in the day. Very curious.

Editor's note: As a cat parent, a large amount of weight loss in a short period of time is always cause for concern. Are you weighing her/him, or did you simply notice that s/he's thinner?

How much weight has s/he lost?

I've never seen a healthy cat lose enough weight in a matter of days so that it was visible, even when you're working with a cat on a fitness program.

If you can see the weight loss, that worries me. If it's a noticeable amount on the scale within a few days, that would concern me too.

Think about a 10 pound cat losing 1 pound in a month. That's 10 percent of body weight in a month. That's a bit too high.

Lisa Pierson says a safe rate of weight loss for a cat is 1 - 2 percent of body weight per week. But that's assuming your cat is overweight and you want her/him to lose weight.

To answer your question, I'm not sure that it's common for cats to lose weight in the spring. Perhaps someone else will come along and tell us their experience.

But I suppose it's possible that increased activity in the spring, with no change in diet could cause some weight loss in an indoor/outdoor cat. Also, cats tend to shed their winter coats and may look skinnier.

There are a number of illnesses that can cause rapid weight loss, though, such as hyperthyroidism, diabetes, cancer, and parasites.

If s/he's had a loss of appetite or gone off food, for whatever reason, s/he may be at risk for hepatic lipidosis or "fatty liver" disease. Do the whites of her/his eyes look yellow?

In any case, rapid weight loss is always something I would check with the vet about. Please give us an update when you can.
-Kurt