If your cat or dog begins shedding weight, you may find yourself feeling very worried. The problem may be something that can be easily managed—or there may be something more serious going on. We asked veterinary professionals and seasoned animal lovers to share insights on possible causes for significant weight loss in pets. Here’s what they had to say:

Sara Redding Ochoa

Sara Redding Ochoa

DVM Veterinary Consultant at doglab.com

Sara Redding Ochoa is a practicing veterinarian in a small animal hospital. With years of experience in the field, she is a treasure trove of knowledge on all things animal related.

There are many reasons that a dog or cat may lose weight dramatically. If a dog or cat has diabetes we will see them lose a lot of weight really fast. Usually, owners notice that their dog is also drinking a lot of water and needs multiple bathroom breaks—or they start having accidents in the house.

Hyperthyroidism can cause cats to lose weight very quickly despite eating. Cats with hyperthyroid will seem like they are eating more than normal but they are losing a lot of weight. This is due to high thyroid activity causing an increase in heart rate and metabolism.

Kidney disease is another cause of weight loss in pets. As pets age, we see kidney disease more commonly. An owner will notice that their pet isn’t eating as much as they normally would and not feeling 100% themselves.

One of the biggest causes of sudden weight loss the we see in pets is cancer. While no one likes to receive that horrible news that their pets have cancer, this can explain sudden weight loss—especially in older pets.

If you notice any extreme weight loss in your pets, it is best to get them to a veterinarian very quickly. Many of these diseases can cause other problems if left untreated; however, with the help of a veterinary professional, these diseases can be easily diagnosed with a simple blood test.

There are a variety of things that can cause a dog to lose weight drastically. The most troubling causes would include things like cancer or heart disease, but parasites or dental problems may also cause a pooch to start dropping pounds. Even things like stress or dietary changes can cause a dog to lose weight.

Significant weight loss can be very serious, so owners should always seek veterinary guidance. No matter what the cause of the problem, prompt action will improve the chances of a full recovery.

Ben Team

Ben Team

Senior Content Editor

Ben Team is the senior content editor for K9 of Mine and has spent most of his adult life working as a wildlife educator and animal-care professional. Ben has had the chance to work with hundreds of different species, but his favorite animals have always been dogs.

Jeff Franklin

Jeff Franklin

Jeff Franklin is the owner of Cobra Canine and has worked with over 10,000 pet dogs and families. He gives dogs and their owners a new leash on life and turns pets with behavioral issues into family assets.

There are a myriad of reasons that could define why your pet’s weight loss has occurred. Pinpointing the root can be tricky, but a few such reasons include health-related issues (such as blockages, illness, cancer, thyroid or other undiagnosed issues), the loss of their human or animal companion within the home or environment they dwell (often causing depression or lack of appetite), as well as mental anguish (even the most fit animals will often lose weight while being boarded for a prolonged period of time – or if not being fed by their ‘person’ but by a stranger).

We have seen even the hungriest of animals choose not to eat when not in their home environment or during their preferred home routine. Regardless of the cause, sudden weight loss should always be documented and thoroughly checked by a veterinarian prior to making your own diagnosis.

When it comes to causes of drastic weight loss in a dog or cat, there are many possibilities. Here are a few of the more common reasons—some of which pet owners may not expect:

Cold – If your pet is primarily kept outside with minimal protection from the elements in winter, the cold climate could actually be affecting their weight. When you are cold, your body does whatever it can to keep warm so it shivers and burns excess fat your body has stored. This is the same with animals. So, if they have prolonged exposure to a cold climate with insufficient protection, warmth or food, they are going to lose weight drastically.

Diet – Animals have dietary needs just as we do, and they also have a recommended calorie intake. If you are not meeting their basic dietary requirements and calorie intake, they are going to lose weight as their body burns through excess fat to ensure it has the energy it needs to function properly. It is best to check with your vet to ensure that your pet is getting everything it needs. Don’t forget, during winter you may want to feed your pet a little extra as it is working hard to stay warm.

Underlying medical condition – Your pet may have an underlying medical condition that you are not aware of that could be affecting your pet’s ability to break food down and get the nutrients it needs. If you are unsure of what is happening, you should take your pet to the vet to rule out anything life-threatening or something that could become life-threatening.

Lucy Harris

Mom & CEO

Lucy Harris is a mom and a CEO at Hello BabyBump.com

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