Critter Culture
10 Reasons Why Your Dog Is Losing Weight

10 Reasons Why Your Dog Is Losing Weight

Critter Culture Staff



Dogs can lose weight for many reasons, some more serious than others. It could be a more active time of year, and your dog's energy output doesn't quite match its food intake. Prolonged exposure to the cold may also result in weight loss.

Don't worry too much if your dog seems generally healthy and hasn't lost more than 10% of its regular body weight. But remember the rule of thumb—always follow your instincts and contact a healthcare professional to know how best to proceed and set your mind at ease.



Close up of border collie dog looking sad on comfy chair in living room stocknroll/ Getty Images

Stress affects dogs' physical health just like it affects humans. A dog could be anxious or depressed for various reasons.

Perhaps they're getting used to the presence of a new dog or pet in the home (one who may or may not be poaching its food). Or maybe your pooch is grieving the death of a companion pet. Moving to a new house or boredom from being left alone for long stretches could also be factored into weight loss.


Dietary changes

lady feeding her dog , cozy kitchen interior, Phynart Studio/ Getty Images

Have you swapped to a new dog food recently? You'll notice if your fur baby doesn't like the updated grub as much as the old kind and is eating less than usual.

You may also have switched to a type of food with fewer calories—a similarly-filled bowl will equal a reduced caloric intake. Consult with your vet to make the healthiest changes.


Dental issues

Dental Brushing Dogs Teeth JodiJacobson/ getty Images

Toothaches and sore gums are the worst—they're painful and suck the pleasure out of eating and drinking or make it downright impossible. If the pain is consistent enough to cause weight loss, you need to take Fido to a vet to address dental disease or other oral health issues.

Oral hygiene promotes a healthy oral microbiome. Without the regular brushing of teeth, there's an imbalance, and the bad bacteria can travel through the body and cause infections of the organs. Take a look inside your dog's mouth if possible, and note abnormalities such as swelling, blood, or broken teeth.


Old age

Older dog sitting on floor kacoates/ Getty Images

It can be hard to accept because your dog is akin to a family member, but pooches don't have the kind of longevity we do. Dogs are considered senior citizens by the time they're around eight years old, and old age means shrinking muscles.

You know your dog best, so if you feel the weight loss has been too quick, consult your vet to ensure your doggy has as good a quality of life as possible in its golden years.


Gastrointestinal issues

Dog vomit in the living room on the floor, sick dog vomitted to cure itself closeup cerro_photography

Let's move on to some of the more serious health issues that could be causing weight loss. Your dog could be shedding pounds due to gut issues such as ulcers and inflammatory bowel disease (IBD). If the stomach and intestines are affected, doggy diarrhea and vomiting may currently be the bane of your existence. Your poor pet has it worse, and you know it.

Constantly throwing up or pooping will make anyone feel miserable and makes it difficult to keep necessary nutrients in the system. Diet, meds, and supplementation can manage this incurable condition.


Kidney or liver disease

Golden Retriever drinking water outdoor PK-Photos/ getty Images

With liver and kidney disease, you may notice other symptoms besides weight loss, such as thirst, vomiting, and diarrhea.

Liver issues cause jaundice, and kidney issues cause stinky breath. Chronic kidney disease can make the body unable to retain protein, which will, of course, lead to malnutrition and decline. Your vet will do urine and blood tests to confirm whether these organs are healthy.


Heart disease

Young man vet examining dog by stethoscope at pet clinic while nurse making notes in background. Ridofranz/ Getty Images

Cardiac cachexia leads to the loss of lean body mass and causes the number on the scale to drop significantly. Heart problems may be accompanied by fatigue and coughing. Heart disease is usually quite far along by the time a dog starts losing weight, and annual check-ups can help limit the damage certain conditions can cause.



A pet dog enjoying the grassy field of a public dog park, scratching his bum along the grass. petesphotography/ Getty Images

Weight loss accompanied by pale gums and hair loss could indicate anemia and the presence of internal parasites.

Tapeworms and whipworms feed on the nutrients in your dog's stomach before your dog can benefit. You may notice signs like lil' buddy scooting to relieve an itchy butt or symptoms such as poor appetite, vomiting, diarrhea, and listlessness. Your vet will do a stool analysis to check for worm eggs, and deworming can solve the problem, as can preventative medication.


Metabolic disorders

Young woman crouching and wiping the floor, her Weimaraner puppy being warned for peeing at home, zoranm/ Getty Images

Metabolic disorders include diabetes and the relatively uncommon Addison's disease. Rapid weight loss is likely if your canine bestie can't control its blood sugar. You'll notice your dog drinking and peeing more than usual and probably having more accidents, too, despite being housetrained. Older female dogs are more likely to be diagnosed with diabetes.



Vet and Labrador retriever THEPALMER/ Getty Images

Cancer is a metabolic disease, but one that deserves its own category. Cancerous tumors feed off the nutrients dogs consume and lead to visible muscle wastage, and this disease also causes discomfort and a low appetite.

Cancer and aging are often connected, so if your older dog is losing weight, you'll want to rule out The Big C with a visit to the vet.



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