Veterinarian-written / veterinarian-approved articles for your dog.

Obesity in Dogs: Overview of Causes and Dangers


Obesity in animals has reached epidemic proportions in America, mirroring the rise in human obesity. The health risks our overweight animal companions suffer also mirror the diseases that put human health at risk. Joint stress and pain, heart and respiratory disease, diabetes and a shortened life span are just some of the diseases associated with obesity. Recent studies show that fat acts as an organ, releasing substances that cause inflammation and affect the body's sensitivity to hormones. Because dogs often enjoy family member status (which in most respects is of great benefit to dogs), they may be fed treats and meals based on the owner's whim rather than the dog's exercise level and current body condition. Many pets will eat even when not hungry because the foods are highly palatable.

Human obesity issues are complicated and multi-factorial. People often eat because of stress, depression or just plain accessibility to high calorie foods. Dogs eat only what they are fed by their human family members, who are completely in control of their dogs' calorie intake. Owners often balk at recommendations to reduce a pet's calorie intake, perceiving it as being asked to deprive their pets. As a result, weight reduction is one of the most difficult issues veterinarians address with pet owners.

Dog Breeds that are Predisposed to Obesity

Labradors, Golden Retrievers, Dachshunds, Shelties, Bassett Hounds, Beagles, Cocker Spaniels, Collies, Cairn Terriers and King Charles Cavalier Spaniels are predisposed to being overweight. Females are also at increased risk. A sedentary lifestyle is another contributor.

Underlying Medical Conditions that can Cause Obesity in Dogs


Hypothyroidism, which leads to sluggish metabolism, is most commonly diagnosed in middle-aged to older dogs. Symptoms may include poor skin and coat quality, multiple ear infections, and even problems with their nervous system. Owners often comment that they do not feed their dogs very much food but the dog still seems unable to loose weight. Diagnosis of hypothyroidism is made via blood work, and treatment is supplementation with an inexpensive medication.

Cushing's Disease

Cushing's Disease (hyperadrenocorticism) is caused by a hormonal imbalance resulting in the over-production of a steroid hormone, cortisol. Cushing's disease increases the appetite, causing the pet to be insatiable. Cushing's disease weakens the muscles, leading to a pot-bellied appearance, further increasing the overweight appearance. In addition to eating a lot, these dogs drink a lot of water, pant a profusely, and are predisposed to infections due to the immunosuppressive effects of the high levels of steroids. Cushing's disease is diagnosed with blood work and is treated with a variety of medications or, if indicated, with surgery. Happily, if treated appropriately, the effects of Cushing's are reversible.


An insulinoma is an insulin secreting tumor of the pancreas which makes the dog very hungry, leading to obesity. These dogs also exhibit weakness at times, as the unregulated production of insulin leads to extremely low blood sugar levels.


Diabetes is a fairly common disease in middle-aged to older dogs. As in humans, the dog's pancreas can fail to make enough insulin. Insulin, a hormone, is needed for the dog's cells to take in sugars for energy production. As a result, the cells of the dog are starving despite high levels of blood sugar. The cells then send messages to the hunger centers of the brain that the animal is starving. The animal eats more and more, becoming obese. Ironically, being overweight antagonizes or makes less effective the cell's response to insulin, so there is a vicious cycle of overeating based on this hormonal disease. The diagnosis is made with blood work and urinalysis. The disease is managed with insulin and high fiber diets. The dog will lose weight because the appetite will become more normal and the dog will be able to utilize energy more appropriately.

False Impressions of Obesity

Some conditions can mimic obesity. An enlarged organ, or a tumor in the abdomen, or fluid accumulation as a result of congestive heart failure may all lead to the false impression of obesity. Any unexplained weight change in your pet, whether it be weight loss or weight gain, should be further investigated by your veterinary health care professional.

You May Also Like These Articles:

How to Change Your Dog's Food

How to Teach Your Dog to Swim

Why Does My Dog Stink?

What You Need to Know in Case of a Canine Emergency

How to Medicate Your Dog's Ears

Disclaimer: This website is not intended to replace professional consultation, diagnosis, or treatment by a licensed veterinarian. If you require any veterinary related advice, contact your veterinarian promptly. Information at is exclusively of a general reference nature. Do not disregard veterinary advice or delay treatment as a result of accessing information at this site. Just Answer is an external service not affiliated with

Notice: Ask-a-Vet is an affiliated service for those who wish to speak with a veterinary professional about their pet's specific condition. Initially, a bot will ask questions to determine the general nature of your concern. Then, you will be transferred to a human. There is a charge for the service if you choose to connect to a veterinarian. Ask-a-Vet is not manned by the staff or owners of, and the advice given should not delay or replace a visit to your veterinarian.