Dog Losing Weight

6 Reasons Why Your Dog is Losing Weight

Medical Contributor:

Dr. Chelsie Narito

Oct 27, 2023

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Has your dog been losing weight recently? Are you worried about what could be causing this concerning symptom in your pet? Is unexplained weight loss always an issue in dogs, or is there ever a situation in which it’s okay?

In the article below, you’ll find a list of some of the most likely reasons why your dog could be losing weight. Although this list does not cover all the possibilities, it can be a good starting point to help you narrow down the issues you want to discuss with your vet. Read on to find out more.


1. Diet and Exercise

Although it may go without saying, it is possible that your dog is losing a healthy amount of weight because you’ve been actively trying to help her do so. If you know you’re working on your pet’s diet and exercise, then there’s nothing to worry about, as long as her weight loss isn’t extreme.

Work with your veterinarian to determine the right course of action for helping your dog lose a healthy amount of weight. The sooner you can get your pet’s weight under control, the healthier she will be in the long run, so take time to make adjustments when you feel they are necessary.

2. Food Intolerance

It is possible that your pet’s weight loss could be related to a food allergy or food intolerance. Pets who are allergic to a specific food ingredient or who have an intolerance for it may develop chronic diarrhea, which can lead to weight loss in a short amount of time. Chronic diarrhea also contributes to dehydration, which can be deadly in pets if left untreated for too long. Additionally, food allergy and food intolerance often cause skin problems like dandruff and hair loss, so look for these signs to help you determine whether or not this could be a risk for your pet.

3. Illness

If your pet becomes sick, she may lose weight because she doesn’t feel like eating very much. She might also have problems with frequent diarrhea and vomiting, both of which can cause weight loss along with dehydration. If your pet is losing weight due to illness, it is extremely crucial to figure out the cause of the problem and work with your vet to treat or manage it.

Acute illnesses can typically be resolved with treatment from the vet. Chronic illnesses, however, may last throughout your pet’s life and may require more careful management to help prevent further weight loss.

4. Pain

Pets who are in pain for a long period of time may also be at risk of unexpected weight loss. Pain often causes pets to feel uncomfortable when they try to eat, and pain can also make pets lose their appetites. If your dog is showing signs of pain such as hiding and guarding behavior, she may be losing weight for this reason.

Talk to your vet to figure out the underlying cause of your dog’s pain. The sooner you get this problem under control, the easier it will be to prevent your dog from losing a dangerous amount of weight.

5. Hyperthyroidism and Cancer

Hyperthyroidism is a specific condition that affects a dog’s thyroid. This condition causes too much of specific types of hormones to be produced in the dog’s body, which can lead to serious symptoms. One of the most common symptoms of this condition is rapid weight loss, especially when seen with excessive hunger.

Cancer may also present as rapid, unexplained weight loss in dogs. Like hyperthyroidism, pets may lose weight while showing other signs of being very sick. Unlike hyperthyroidism, however, cancer typically causes a loss of appetite instead.

6. Old Age

Finally, it is possible that your pet could be losing so much weight simply because she is aging. As pets get older, they lose some muscle mass and body weight, and they may look thinner and frailer than they once did. Although it can be sad to see your aging dog like this, it is a normal part of life and should be expected during her twilight years.

Contact VEG if Your Dog is Losing Weight

If you think your dog is losing weight due to old age, talk to your vet for more information. Your vet can help you rule out any health problems and choose a good quality food blend designed to help senior dogs retain healthy weight.

As you can see, many of the causes of weight loss in dogs are concerning ones. Even the milder ones typically need to be addressed by a veterinarian, so unless you have been actively trying to help your dog lose weight, it’s a good idea to see your regular vet as soon as possible about this issue.

Additionally, if your dog’s weight loss is very sudden and is accompanied by other concerning symptoms like dehydration or confusion, you should consider seeing an emergency vet quickly instead. For questions about weight loss in dogs, call any of our VEG locations now. All of our locations are open 24/7, with emergency veterinarians on staff who are ready to answer any questions you have regarding your pet’s health. With our team, you can be rest assured that your dog will always get the care they need.