Overweight in Dogs

Why is my dog overweight?

What is Overweight?

If you notice your dog has put on extra weight and is slowing down due to his larger size, he may be joining the growing number of overweight and obese pets.  According to the Association for Pet Obesity Prevention, a staggering 54% of dogs in the United States are classified as obese.  When your dog is overweight, he will have an accumulation of excess body fat.  Though the demarcation line for overweight versus obese is the subject of debate; generally, if your dog is between 10 and 20% above ideal then he is considered overweight.  If his body weight is 20% or greater over his ideal mass, he is considered obese. 

Several factors can contribute to an overweight dog.  Additionally, being overweight can increase your dog’s risk to other diseases such as heart and kidney disease, diabetes, arthritis, and can decrease your pet’s life expectancy.  The common factors affecting a dog’s weight can be environmental or medical in nature, such as:

  • Overfeeding and lack of exercise
  • Age and genetic predisposition
  • Hypothyroidism
  • Cushing’s disease

Why Overweight Occurs in Dogs

Excess fat on your dog’s body can be from environmental or medical conditions.  Many people are unaware of the extra weight their dog may have put on, especially as their dog ages.  Conversely, some medical conditions may be the reason for the excess weight.

Overfeeding and Lack of Exercise

Overfeeding is common among dogs. Dogs are scavengers and in nature, will feed beyond their limits in case food becomes scarce.  Domestic dogs have this same nature and will continue to eat until the food is gone.  If you allow your dog to graze his food, he may eat a little at a time, but he will always return to finish it.  Treats also go unnoticed by pet owners and some people will supplement their dog’s food with excessive, high-calorie treats and scraps. 

Without adding additional exercise, your dog is at risk for putting on extra weight.  Indoor dogs, who don’t get the opportunity to run around as much, may also become overweight in time.  Age and genetic predisposition can also contribute to excess fat gains.

Age and Genetic Predisposition

As your dog ages, he will start to slow down.  Your dog’s metabolic rate will decrease, and he will lose lean muscles mass as fat mass increases.  Without making adjustments to diet and exercise, your dog runs the risk of gaining weight.  Additionally, some breeds have a predisposition for weight gain as well, including Labrador Retrievers, Miniature Schnauzers, Dachshunds, Shetland Sheepdogs, Cocker Spaniels, Beagles, Basset Hounds, and Cairn Terriers.


Your dog may be suffering from a hormonal imbalance if you can rule out environmental factors contributing to your dog’s excessive weight gain.  The thyroid gland produces hormones regulate metabolic functions.  An under-active thyroid may lead to hypothyroidism and is most common in medium to large breeds between the ages of 4 and 10.  Many times, the symptoms of hypothyroidism appear like “aging” but additional symptoms to look for include low blood pressure, a thinning coat, intolerance to the cold, and vocalization changes (raspy bark).    

Cushing’s Disease

Another hormonal imbalance, associated with the pituitary gland, may cause your dog to gain excessive weight.  Hyperadrenocorticism, known as Cushing’s disease, is an overproduction of the hormone, cortisol.  Cortisol in higher levels in the body can cause your dog to gain weight, experience fatigue, lose hair, and have skin problems.  Cushing’s disease can develop with the excessive use of anti-inflammatory medications or by damage and disease of the pituitary or adrenal glands. 

What to do if your Dog is Overweight

If your dog’s weight problem appears to be the result of age, overeating, and decreasing exercise you can develop a health plan with your veterinarian to regain your dog’s ideal weight.  A diet plan may include lowering your dog’s carbohydrate meals, decreasing high caloric treats, and maintaining a strict portion and timing for meals, even if your dog is a grazer.  

When you change your dog’s diet, you should transition him over the course of a week, especially if you are giving him a new food.  The transition will help ease your dog into the change.  Exercise, though moderate, is also necessary.  Your dog may spend a lot of time indoors and sedentary.  Getting him outside and walking will help him burn extra calories, build and maintain lean muscle, and contribute to his overall health.  It is also important to be patient and diligent with your pet’s new weight management plan.  Just like with people, changes do not occur overnight, and the goal is to reduce weight and build lean muscles safely.  

Some medical reasons for excessive weight in dogs, like hypothyroidism, cannot be cured.  However, your veterinarian can develop a treatment plan to manage the disease that includes hormone therapy.  You can expect to make regular visits to the veterinarian for testing as your dog’s body will develop a tolerance for the drugs.  The hormone replacement therapy will continue throughout your dog’s life.  

If your dog is suffering from Cushing’s disease, your vet will need to determine the underlying cause of the disease.  Treatment may include medication, given over the lifetime of your dog, surgery to remove any adrenal tumors that are damaging the glands, or radiation to reduce tumors and masses affecting the glands. 

Prevention of Overweight

A healthy lifestyle is the first measure to take to prevent obesity in your dog, but you also need to know what your dog’s ideal weight is and how to measure it.  The rib coverage test is the most efficient way to determine your dog’s health.  The ribs must be felt, similar to the feeling of running your fingers over your knuckles.  

Once you are comfortable gauging your dog’s weight, you can develop a diet to support a healthy lifestyle, and stick to it.  It is also important to know the difference between a begging dog and a hungry dog.  Dogs may not be begging because they are hungry but because it gets them attention.  Rewarding the begging with a treat or food will strengthen the behavior.  

Limiting treats and table scraps will also significantly help reduce the risk of becoming overweight.  Often, we don’t count treats and table scraps as meals, and the dog may be eating high caloric foods as well as his meals. 

You cannot always prevent the medical conditions that may be associated with an overweight dog, like hypothyroidism.  But maintaining a healthy lifestyle with appropriate feeding and moderate exercise can significantly reduce the risk of becoming overweight.

Cost of Overweight

The cost of treating an overweight dog depends on the underlying cause.  For example, the cost of treating an overweight dog associated with overfeeding can be as little as $220.  However, treatment for Cushing’s disease can be around $2,000.

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