Reasons Your Pet Might Be Losing Weight

dog and cat

Most of us are guilty of sometimes overindulging, and in addition to feeding ourselves a little too much, we often pass extra treats and scraps to our pets. This is also reflected in the pet obesity figure, which has steadily risen over the last few years in line with the human obesity crisis, with studies showing that more than 50% of cats and dogs in the U.S. are now classed as overweight or obese.

With these stats in mind, it is easy to see why many of us would be delighted to find that we have shifted a fair few pounds in weight without any real effort. However, dramatic and unexplained weight loss in a pet should always be a concern, and something that is checked with your veterinarian. In many cases, a pet may lose weight for several, innocuous reasons. However, in other instances, there may be an underlying disease or condition that is causing your pet to lose weight. If the latter is true, then your pet may require immediate professional treatment.

When not to worry that your pet is losing weight

Certain changes in your pet’s lifestyle can cause a temporary bout of weight loss, which usually rectifies itself once the situation becomes more stable or your pet adjusts to the change.

Some of the most common reasons that a pet may lose weight can be:

- Due to a change in your pet’s diet. The food you are now offering may be less appealing to your pet, so he may be eating less, or it may be lighter in calories, causing him to lose weight.

- An increase in the amount of exercise your pet is doing. Perhaps you have a new routine that involves a longer walk, or you are spending more time playing together.

- The stress of a new house or new person in your home could affect your pet’s eating habits, which could cause him to lose weight.

- Recent vaccinations or new medications. Some pets feel a little under the weather after they have had vaccinations, which can affect their appetite. Similarly, a side effects of some medications is appetite or weight loss.

- Older pets naturally lose a little weight as part of the ageing process.

Worrying reasons that your pet might be losing weight

Unfortunately, unexplained weight loss can be a symptom of a more serious, underlying condition affecting your pet. Here are some of the more worrying reasons that your pet might be losing weight.


Internal parasites such as hookworms, tapeworms and whipworms can both interfere with your pet’s appetite and affect the ability of your pet to absorb the nutritional value of their food. This in turn can cause your pet to lose weight. Some varieties of internal parasite can spread to the human members of your family, so seeking treatment should be a priority. There are a range of preventative treatments available for protection against parasites, so speak with your veterinarian about which ones can help to prevent your pet from becoming infected with them in the future.

Dental problems

Trying to eat when you are suffering with dental problems can be virtually impossible for both humans and pets. If your animal is experiencing pain with their teeth and gums, it may be affecting both their appetite and their physical ability to consume food. Thankfully, most vets offer dental care as part of their services, making it relatively simple to get any dental problems diagnosed and treated quickly.


There are a range of different illness that can cause your pet to lose weight, some more serious than others. When illness is to blame for your pet’s unexplained weight loss, your vet will normally have to consider any other symptoms that your animal may have, as well as potentially running a panel of tests to help identify the underlying cause.

Some of the illnesses that can cause unexplained weight loss include diabetes, gastrointestinal problems, thyroid problems, Addison’s disease and liver disease. Many of these conditions can be effectively managed or treated, and the sooner you seek professional care for your pet the greater the likelihood that they will be able to regain their health.

If your pet is losing weight, don’t wait to see if the situation rectifies itself. Make an appointment with Dr. Sands at Parkland Animal Clinic for a full check on your pet’s health.

Providing the very best in veterinary care, and the ability to establish innovated programs.


Parkland Animal Clinic & Big Bear Pet Lodge​​​​​​​
8017 N. University Dr
Parkland, FL 33067

Fax: 954-757-3990