Why Is My Dog Gaining Weight?

Plump babies, pudgy puppies -- humans seem drawn to chubby things. But when dogs and their people grow up, the health effects of being overweight can be far from cute.

What are the dangers of weight gain in dogs? What are some common causes of weight gain? And when is it time to talk to a vet about your overweight pet?

Weight Gain in Dogs: Common Causes and Treatments

More than half of all dogs in the U.S. are overweight or obese. Being heavy puts our pets at higher risk for arthritis and shortens life expectancy. In addition, obesity has been associated with numerous other problems in dogs, such as certain tumors, high blood pressure, and heart disease.

To avoid weight gain, calories burned must equal or exceed calories consumed. It’s as true for your pet as it is for you.

And just as with people, many things can cause your pet to gain weight -- from eating too much to getting too little exercise to having a chronic illness. Because we’re not always the best judges of our dog’s physique, it’s a good idea to talk to your vet if you think your dog may be overweight -- especially if the weight gain is sudden.

Some common reasons dogs gain weight include:

Too much food. Often we’re not sure how many calories we need to maintain a healthy weight. So, it’s understandable we may overestimate the energy needs of our dogs. And overestimate we do.

Age can be one reason for the calories-in-calories-out imbalance. That’s because as our pups grow older they often exercise less. Yet, we may continue to feed them the same quantity of food we’ve always done. The result: weight gain.

A dog’s calorie needs can be surprisingly small. Little dogs that aren’t very active need as few as 185 to 370 calories a day. A dog weighing between 67 and 88 pounds may need between 1,100 and 1,700 calories a day.

If those figures surprise you, or if your dog is 10% to 15% above ideal body weight, it’s time to talk to your vet about what you can do to get your dog to maintain a healthy weight.


Not enough exercise. Getting too little exercise is another common reason dogs gain weight.

The amount of exercise your pooch needs to thrive depends on its breed, age, and size. But a good goal is to aim for at least 20 to 60 minutes of activity with your dog each day. Be careful. If your pets haven’t had much activity lately, don’t suddenly take them for a three-mile run. Get exercise tips from your vet and then start any new workout plan for your pooch slowly.

Chronic illness. Chronic conditions like Cushing’s disease (hyperadrenocorticism) or hypothyroidism can also cause weight gain in dogs.

Dogs get Cushing’s disease when their adrenal glands produce too much cortisol, a chemical that helps them respond to stress, controls their weight, fights infection, and keeps blood sugar levels in check. Along with weight gain, symptoms of Cushing's may include excessive hunger and thirst, heavy panting, a pot-bellied appearance, and hair loss. How hyperadrenocorticism is treated varies, but your vet may suggest adrenal-suppressing drugs or surgery to remove an adrenal tumor.

An underactive thyroid (hypothyroidism) is a common problem in dogs and can also be behind your dog’s weight gain. Certain breeds, including Doberman pinschers and golden retrievers, are more prone to hypothyroidism. Symptoms may include lethargy, hair loss, weakness, infection, and less tolerance for exercise. Hypothyroidism is easily treated with hormone replacement therapy.

Other Causes of Weight Gain in Dogs

Genetics plays a part in your dog’s tendency to gain weight, too. Some breeds are just more prone to putting on weight than others.

The breeds more inclined to be obese include American cocker spaniels, basset hounds, beagles, Cairn terriers, Cavalier King Charles spaniels, dachshunds, Labrador retrievers, Norwegian elkhounds, rough collies, and Shetland sheepdogs.

Dogs which have been spayed or castrated are also more likely to be obese, probably because neutering affects energy expenditure and metabolism.

How to Tell if Your Dog Is Overweight

Take a look at your pet. Your dog’s at a healthy weight if:

  • When looking at your pooch from above, you see a noticeable waist.
  • From a side view your dog’s belly tucks up as it leads to its hind legs.
  • You can feel your dog’s ribs without pressing hard at the sides.


Now weigh your dog. You can take him to your vet’s office to use a walk-on scale or weigh him at home (if he is not too big). The easiest way to do this is to:

  • Weigh yourself and then note the number.
  • Pick up your dog.
  • Step back on the scale and record the combined weight of you and your dog.
  • Subtract your weight from the combined weight.

You now know your dog’s weight. However, vets typically look at body condition rather than a number on the scale to determine overweight or obesity.

When to See a Vet

Concern about your pet’s weight is all the reason you need to consult your vet.

Your vet can not only diagnose the cause of your dog’s weight gain, but also help you form a realistic, safe weight loss plan for your pet. Crash diets are as bad for your dog as they are for you. Weight takes time to put on, so time is needed to safely take it off. Your vet can help you figure out the most effective way to do that.

WebMD Veterinary Reference Reviewed by Amy Flowers, DVM on August 13, 2017



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Golden Retriever Rescue of Mid-Florida, Inc: “Is Your Dog Overweight?”

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