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7 Ways Obesity is Killing Your Pet

By Colleen Williams and medically reviewed by JoAnna Pendergrass, DVM
February 25, 2016 • 6 min. read
fat dogs

It’s official: the majority of dogs and cats in the United States are fat. Well, overweight or obese that is; the distinction lies in the amount of excess body fat. If a pet’s weight is at least 20% higher than ideal, an official diagnosis of obesity is given. The Association for Pet Obesity Prevention‘s most recent annual study, conducted in 2018, reported that 55.8% of U.S. dogs and 59.5% of cats are overweight or obese. It’s so common for American pets to be overweight that it’s ingrained in our culture through the politicized image of “fat cats” – smug, greedy and wealthy donors.

Adorable as an animal’s Michelin Man folds may be to some, these extra pounds can have extreme impacts on the health and welfare of a pet. In 2014, a Canadian woman was charged with animal cruelty after allowing her cat Napoleon to reach 25 pounds, despite vets’ warnings. Unable to groom himself, Napoleon developed painful and extensive skin irritation that proved incurable; euthanasia was deemed the most humane option.

Some quick ways to see if your pet may be obese are to feel their ribcage and look at your pet from the top down. If you can’t feel your pet’s ribs and you can’t see their waist when looking down, it’s time to visit the vet for a more official weigh-in. Luckily for you and your pet, obesity is reversible! Changes to diet, exercise and overall lifestyle can help pets to shed pounds. Take action now to ensure your pet stays at a happy, healthy weight – before it’s too late.

To be fair, some dog breeds, like Bulldogs, are naturally rotund. For these pudgy breeds, consider the breed standard for weight and check with your veterinarian before automatically concluding that the dog is obese.

1. Heart Disease

fat dogs
Coughing or wheezing while exercising are one indicator of heart disease, especially in obese dogs. (

The most significant obstacle for obese pets is their increased body mass. Although the animal increases in size externally, the internal organs, like the heart, don’t get bigger and are forced to work harder to keep this bigger body going. An overworked heart pumps faster but cannot keep pace with the body’s circulation needs, leading to congestive heart failure. Congestive heart failure is manageable for a time. Eventually, though, the heart will give out, leading to the death of an affected pet.

Coughing is an unexpected but important sign of heart disease in pets and is caused by an enlarged heart compressing the lungs. (It’s also a symptom of heart worms!) For this same reason, difficulty breathing or avoidance of exercise may also indicate heart disease. Poor oxygen flow can also be visible in bluish gums or tongue as well as fainting. Abdominal swelling occurs as the condition advances, the result of fluid accumulating.

Treatment and prognosis for a pet with heart disease depends on its severity and the type of illness. As with most medical conditions, the earlier it is caught, the better chance a dog or cat has of surviving.

2. Joint Disease

hip dysplasia in dogs
Hydrotherapy is an emerging treatment for hip dysplasia in dogs, especially seniors. (

Obese pets are under pressure in more than one way; all that extra tissue weighs heavily on joints and ligaments, increasing the risk of injury and degenerative disease. Senior dogs and cats are especially susceptible to developing joint diseases, as their cartilage is already weakened by age. Osteoarthritis is one of these conditions, caused by a decrease of cartilage that results in painful bone-on-bone contact within joints. Extremely painful for pets, arthritis is not curable but is manageable through a combination of surgery, medication and physical therapy.

Hip dysplasia, another degenerative joint disease, is genetic. Large-breed dogs like German Shepherds and Labrador Retrievers are at a genetically higher risk of developing this condition. In hip dysplasia, the hip’s ball-and-socket joint, which connects the pelvic bone with the femur (thigh bone), is ill-fitting as a result of malformation. Being obese and genetically predisposed to hip dysplasia is like a double-whammy for this joint disease. Pet parents can’t prevent hip dysplasia, but they can reduce its severity and progression through lifestyle management, which includes healthy weight maintenance.

The anterior crucial ligament (ACL), which helps to stabilize the knee, is also vulnerable to traumatic injury in obese dogs and cats, once again because of the increased strain it is under.

3. Neurologic Disease

Intervertebral disc disease (IVDD), which is common in small dog breeds, occurs when the spine’s shock-absorbing discs get squeezed or burst out of the spinal cord, causing painful compression of compressing the spinal cord and spinal nerves. IVDD can be caused by trauma, such as a hard fall, genetic predisposition, or from the extra pressure of obesity.

4. Diabetes

Daily insulin injections are essential for managing Type I diabetes in dogs. (Thinkstock)
Daily insulin injections may be needed to manage diabetes in obese pets. (Thinkstock)

The bodies of fat dogs and cats do a poor job of responding to insulin, the hormone that keeps blood glucose (sugar) levels in check. The excess fat makes cells resistant to insulin, driving up blood sugar levels. The pancreas continuously pumps out insulin to counteract high blood sugar levels, but to no avail, resulting in diabetes mellitus (type 2 diabetes), commonly known as insulin-resistant or “sugar” diabetes.

This is different from type 1 diabetes, which is present at birth and is the result of the pancreas’s inability to produce insulin. In general, cats are more prone to type 2 diabetes. Dogs are more likely to get type 1 diabetes, but can develop type 2 diabetes if they’re obese.

Symptoms of diabetes in dogs and cats include excessive thirst and urination, decreased appetite, weight loss, lethargy and vomiting. Depression can even result in some pets if diabetes is left untreated, as can cataracts and kidney disease. A prescription diet and insulin are typically required as part of diabetes management to keep blood sugar levels in the normal range.

5. Decreased Quality of Life

obese cat
Obese pets have limited mobility, especially when grooming. This can lead to skin irritation and matting. (

The effects of obesity in pets are far-reaching and impact every part of a dog or cat’s life. Exercise becomes difficult and breathing labored as lung capacity decreases and the diaphragm is pressured by excess fat. The bigger the body, the more oxygen it needs, placing the lungs under increased demand. Brachycephalic, or flat-faced, breeds – such as Pugs, Persians and French Bulldogs – may find breathing restricted even more with weight gain.

Poor body temperature regulation is another rarely-considered side effect of obesity. Overweight pets are less capable of regulating their internal conditions because of their layer of insulating tissue. Constantly warm, this places overweight pets at an increased risk of developing heat stroke in the summer. Conversely, in the winter they may also struggle due to decreased circulation, making frostbite or hypothermia a possibility.

It’s the little things that really affect a pet’s quality of life. Fat dogs and cats are less flexible and can’t maneuver themselves for full-body grooming, which can lead to skin and coat issues. If not properly distributed, the fur’s natural oils accumulate and cause fur matting or painful sores. An unhealthy, high-fat diet can contribute to coat troubles but also to gastrointestinal discomfort and flatulence – unpleasant for everyone involved.

6. Poor Immune Function

Studies in both humans and animals have demonstrated that obesity leads to reduced immune function, making individuals more susceptible to infection. The Obesity Action Coalition posits this is due to poor diet and lack of exercise and even theorizes that obesity might make vaccines less effective. If your pet is constantly sick with the common cold or other infections, talk to your vet about strengthening your pet’s immune system while you tackle shedding pounds with your pet.

7. Increased Risk During Surgery

French bulldogs
Obese pets have a higher risk of complications during and after surgery. (

All of the previously discussed risks for obese pets are heightened when it’s time to go under the knife. Cardiovascular and respiratory systems are already stressed from supplying super-sized systems; introducing anesthesia as an extra stressor places obese pets at an increased risk during surgery. Anesthesia is metabolized through the body’s fat stores; because of this, obese pets are more difficult to dose and take longer to wake up afterwards. Often vets are forced to tell pet parents that the risk of surgery is higher than the medical condition itself, thanks to the animal’s extreme weight. Additional anesthesia, as well as extra staff to monitor an obese pet, can also drive up the cost of common surgeries for pet parents.

Increased fatty tissue lengthens pets’ time spent on the table. Also, layers of fat obscure the intended surgical site – say, the bladder – making the procedure more technically difficult.

Taken together, obesity worsens pre-existing medical conditions, making a pet’s prognosis less positive. For example, age-related arthritis is common and easily manageable, but can be even more painful because of obesity. This, in turn, increases the difficulty of weight loss and further compounds pets’ health issues.

If your pet is obese, be proactive about helping them lose weight and maintain that weight loss. Your veterinarian can help you come up with the ideal weight loss plan for your pet to improve your pet’s life.

The content is not intended to be a substitute for professional veterinarian advice, diagnosis, or treatment. Always seek the advice of your veterinarian or other qualified health provider with any questions you may have regarding a medical diagnosis, condition, or treatment options.

colleen williams
By Colleen Williams

Over the past decade, Colleen has written about health, wellness, beauty, and even pets for The New York Times, The Cut, Refinery29, xoVain, Healthy Paws Pet Insurance, and Seattle Met Magazine, as well as many beauty brands. She has a BFA in Art History from the University of New Mexico and an AAS in Fashion Design from Parsons School of Design in New York.

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joanna pendergrass
By JoAnna Pendergrass, DVM

JoAnna Pendergrass, DVM, is a veterinarian and freelance medical writer in Atlanta, GA. After graduating from the Virginia-Maryland College of Veterinary Medicine with her veterinary degree, JoAnna completed a 2-year research fellowship in neuroscience at Emory University. During this fellowship, she learned that she could make a career out of combining her loves of science and writing. As a medical writer, JoAnna is passionate about providing pet parents at Healthy Paws with clear, concise, and engaging information about pet care. Through her writing, she strives not only to educate pet parents, but also empower them to make good health decisions for their pets. JoAnna is a member of the American Medical Writers Association and Dog Writers Association of America.

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