5 Factors That Can Affect Your Senior Dog’s Weight

Weight change in dogs can be caused by a variety of factors.

“As dogs age, they develop many diseases that can cause general malaise, negatively impacting their appetites,” says Dr. Wendy Hauser, DVM, AVP of Veterinary Relations, Crum & Forster Pet Insurance Group, provider of ASPCA Pet Health Insurance. The same is true of medical issues that can lead to weight gain.

“And there are also some diets that are not digestible enough to maintain a healthy weight,” Hauser says. “I have seen senior dogs stop eating foods due to a change in the formulation of the food as well.” Here are some factors that can lead to weight loss or gain in senior dogs.

Dental Issues

Dental disease can certainly lead to weight loss in older dogs, or any dog for that matter, says Dr. Antje Joslin, DVM, Veterinarian at Dogtopia, a one-stop dog care facility. “Severe dental disease that causes loose, infected or painful teeth can certainly affect a dog’s ability to eat and can in turn, can lead to weight loss,” Joslin says. “Plus, severe dental disease can contribute to other diseases, such as heart and kidney disease, which can also lead to weight loss.”

If you’re concerned about dental disease in your senior dog, Joslin recommends being in the lookout for foul odor, plaque, and tartar on the teeth, discolored or mobile teeth, or red, swollen gums. “In some cases, many dogs with severe dental disease will continue to eat like normal, so weight loss or decreased appetite are by no means the only signs of dental disease,” says Joslin.

Loss of Appetite

While many older dogs may experience mild fluctuations in their weight as they age, decreased appetite and weight loss in older pets can be a sign of serious illness, according to Joslin.

“Some older dogs will experience a decrease in their sense of smell and may need slightly more aromatic or enticing foods to eat, but the vast majority of healthy, older dogs continue eating as normal,” says Joslin. “Therefore, if you notice unplanned weight loss or a lack of appetite in your dog, a visit to your veterinarian is warranted.”

Serious illnesses such as cancer, kidney disease, and liver disease can all cause nausea and a loss of appetite, so it’s important to see a vet right away if you notice your dog has lost interest in food.


Diabetes in dogs occurs when the dog’s pancreas cannot produce adequate insulin, which in turn helps blood sugar (glucose) to be absorbed from the blood and used as an energy source by the body, explains Hauser. “Because the glucose is not being absorbed as an energy source, early in the disease dogs have markedly increased appetite and weight loss,” explains Hauser. “If left untreated, the dogs continue to lose large amounts of weight, becoming skeletal.”

Conversely, some factors can cause senior dogs to gain weight.

Less Activity

As pets get older, it’s normal for them to slow down. “Most older dogs are still happy to go for walks, or play catch and interact with their housemates,” says Joslin. “But they enjoy a great deal of time spent napping and relaxing.

Slowing down is a normal part of aging in our pets, and it’s in part connected to a decrease in muscle mass and a decrease in metabolic requirements. “Many senior dogs have additional factors that contribute to this slowing down or decrease in activity, including being overweight, having chronic pain, issues with joints and mobility, and difficulty seeing or hearing,” says Joslin.

If your dog is suddenly moving a lot less than he used to but still eating the same, chances are he’ll start gaining weight. To avoid this, Joslin says it is important to keep your dog active with appropriate exercise and mental stimulation. You might also need to switch to a different SOMETHING OTHER THAN KIBBLE especially formulated for senior dogs, which is likely lower in fat and calories.

Cushing’s Disease

Cushing’s disease (hyperadrenocorticism) is a disease that affects middle to older age dogs and it results from an overproduction of a hormone (glucocorticoids) produced in the adrenal glands in small amounts, according to Hauser. “Clinical signs of Cushing’s Disease in dogs include significant increases in water consumption, a pot-bellied appearance, weight gain, and panting,” says Hauser.

In addition, dogs with Cushing’s disease are often overweight, lethargic, and have exercise intolerance, says Joslin. “Dogs that have Cushing’s disease or are taking steroid medications, like prednisone, are often excessively hungry and thirsty and therefore gain weight,” Joslin says.

Meet the Author: Diana Bocco

Diana Bocco is a full-time writer and avid adventurer. She's gone hiking in Siberia, snorkeling in Thailand, and canoeing in the Mekong River. She also loves caves and has been known to get lost in one or five around the world. Diana's work has been published in the Discovery Channel website, Yahoo!, Popular Mechanics, and more. You can read more of her work on her website at www.dianabocco.com

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