What Causes Increased Appetite in Dogs?

What Causes Increased Appetite In Dogs?

No matter how much food you give your dog, he still acts like a bottomless pit—following you around and parking by your table begging for scraps. Although this insatiable hunger can stem from canine biology, an appetite above the norm may be cause for alarm.

Read on to find out just what may be causing an increased appetite in your dog.

Canine Biology

To understand a dog’s seemingly bottomless pit of a stomach, just look to canine biology. The dog’s nearest wild relative, the grey wolf, has survived by adapting to a feast-or-famine mentality. When fresh prey is abundant, the grey wolf can intake large amounts of food, stocking up for days where prey may be scarce.

Be sure to look out for food caching, such as burying bones in the garden, or scavenging—burrowing through the kitchen trash can.

Yes, a dog’s growing appetite may be due to his canine biology. When a dog increases his food intake to the extent of ravenousness, though, the condition is referred to as polyphagia: excessive eating or swallowing.

Causes of Increased Appetite in Dogs

Increased appetite or polyphagia can be brought on by various circumstances. If the polyphagia stems from a disease, you will most likely notice one of two physical effects: weight gain, or weight loss. But a dog’s increased food consumption can also stem from a psychological condition. If the polyphagia is due to a psychological issue, the dog has likely developed a learned behavior which could lead to obesity.

What Causes Increased Appetite In Dogs?

Leading causes of increased appetite, or polyphagia, include:

Old Age

If the polyphagia is related to a behavioral problem, the underlying cause could stem from old age. When dogs increase in age so can their appetite, too. The reason? Medications prescribed for old dogs can cause an increase in appetite.


Like humans, dogs can develop diabetes. Diabetes in dogs is a disease in which the body’s ability to produce or respond to the insulin hormone is impaired. This results in the irregular metabolism of carbohydrates and elevated levels of glucose, in the blood and the urine.

Despite the excess of glucose present, a lack of insulin means that the glucose is blocked from the body’s cells. The cells respond by signaling the animal to intake more food, resulting in an abnormally large appetite.

Cushing’s Disease

Cushing’s Disease in dogs refers to the overproduction of the hormone cortisol. Also known as Hyperadrenocorticism, it is one of the most common endocrine disorders in dogs.

Cushing’s Disease can also increase appetite with the overproduction of glucocorticoid—the hormone that helps dogs manage stress.

Conditions Causing Malabsorption in Dogs

Oftentimes, an increase of appetite can stem from an underlying disease: one which results in malabsorption. Malabsorption refers to the inability to properly absorb nutrients from food, which results in extra levels of hunger. Most of the time these conditions are accompanied by telltale symptoms like diarrhea and/or vomiting.

Leading conditions causing malabsorption include:

  1. Exocrine pancreatic insufficiency (EPI): most commonly found in German Shepherd dogs, EPI is a condition which results in a decrease of the enzymes needed to digest food. As a result, food can pass through the digestive tract without breaking down, thus causing a lapse in absorption.
  2. Small intestinal bacterial overgrowth (SIBO): SIBO is a condition which damages the walls of the small intestine with bacteria. This results in reduced nutrient absorption and increased appetite. SIBO can develop alongside EPI, but also occurs as the primary condition.

Force of Habit

While the aforementioned causes are medical, research suggests psychological causes as possible perpetrators to a dog’s polyphagia.

Surely it is difficult to avoid a dog’s warm, sad eyes when he looks to you for a treat. However, feeding a dog in response only reinforces this ask, strengthening this food-seeking behavior over time. And, since the dog eats, the owner presumes he was truly hungry. This results in an unfortunate cycle—a psychologically learned behavior—which can lead to increased appetite.

Symptoms of Increased Appetite in Dogs

Now that you know what causes increased appetite in dogs, how do you know if your furry friend truly has polyphagia—or if he’s just hungry?

What Causes Increased Appetite In Dogs?

Aside from overeating, the symptoms typically associated with polyphagia include:

  • Obesity from overeating
  • Increased appetite
  • Weight gain or weight loss
  • Increased thirst, or polydipsia
  • Increased frequency of urination, or polyuria
  • The inability to absorb food properly

If your dog exhibits these symptoms, take him to the vet. Your veterinarian will perform the proper tests and exams to diagnose and treat your furry friend.

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