By Dr. Karen Shaw Becker
Most dogs are good eaters, which is a nice way of saying they'll eat anything that isn't nailed down. Dr. Jules Benson, Vice President of Veterinary Services at Petplan Pet Insurance, explains the phenomenon this way:
"Looking at the domestic dog's nearest wild relative, the grey wolf, they are adapted to a feast-or-famine diet and can go many days without fresh prey. They achieve this through eating large amounts when food is available, food caching (may be analogous to burying bones in the garden!) and scavenging (watch out for the kitchen trash can!)."1
In other words, it's natural for our canine companions is to eat whenever food is around, and not necessarily because they're hungry right that second, but because they never quite get it through their doggy brains that mom or dad will continue to make meals available like clockwork every day of their lives. Sadly, it's also possible some adopted dogs harbor memories of starvation from earlier life experiences, and will forever view food as a rare and precious resource.
With that said, it's often difficult to tell if a seemingly food-obsessed dog is just following his natural instinct to eat at every opportunity, is driven by a fear of starvation, is being fed a diet that doesn't nourish him at the cellular level (more about this shortly) or has simply mastered the art of manipulating his humans for food and treats.
A less likely but potentially serious possibility is an underlying medical condition that causes your dog to feel excessively hungry, no matter how much he eats. That's why I recommend making an appointment with your veterinarian if your dog seems to be extra hungry even though he's eating well, and especially if he's also losing weight.
4 Serious Diseases That Can Cause Excessive Hunger in Dogs
1. Cushing's disease. The medical name for Cushing's is hyperadrenocorticism. Hyperadrenocorticism, loosely translated, means "too much cortisol released by the adrenal glands." Cortisol is the fight-or-flight hormone. In a healthy dog's body, cortisol is released by the adrenal glands intermittently, in small amounts, in response to perceived stress and the possibility the dog might have to do battle or run for his life.
However, if for some reason your dog's body upregulates its demand for cortisol, the adrenal glands begin overproducing the hormone, which can lead to a state of toxicity. When cortisol is released by the adrenal glands, it triggers a release of glucose from the liver.
Your dog needs cortisol in small amounts, however, if he experiences chronic stress, his adrenals will release too much in response. Chronic stress leads to persistent oversecretion of cortisol. Extreme hunger is one of the symptoms of Cushing's and results from the body burning all that extra glucose.
2. Diabetes. Unfortunately, Type 2 diabetes is all too common today in dogs approaching middle age and their senior years. Adult-onset diabetes in dogs is a result of a lifestyle that leads to decreased production of insulin or the inability of the body to use it efficiently (insulin resistance).
Obesity is by far the biggest reason pets become diabetic. Your dog has no biological requirement for grains or most other carbohydrates (starches), yet carbs can be as much as 80 percent of the ingredients in processed pet food. Carbs turn into sugar in your pet's body and excess sugar leads to diabetes.
Unfortunately, starch is required for the dry food manufacturing process, so even grain-free foods contain an abundance of sugar in the form of tapioca, potato, pea and other legumes that stress your pet's pancreas. Another lifestyle-related reason pets develop diabetes, one that often goes hand-in-hand with poor nutrition, is lack of physical activity.
3. Hyperthyroidism. Hyperthyroidism is typically seen in older cats. It's an uncommon condition in dogs, and in most cases, the cause is an aggressive thyroid tumor that overproduces thyroid hormone. The only other recognized cause, which occurs very rarely, is the ingestion of thyroid hormone from other sources, such as active thyroid tissue contained in raw diets.
Your dog's body temperature, heart rate, food utilization and other functions depend on the appropriate level of thyroid hormone in the bloodstream. Hyperthyroidism means the glands are working overtime, secreting too much hormone, which causes a constant state of metabolic hyperactivity.
Pets with the condition typically lose weight despite being constantly hungry, drink excessive amounts of water and urinate excessively, have increased heart rates, and also vomiting. Left untreated, hyperthyroidism can result in heart and kidney failure.
4. Exocrine pancreatic insufficiency (EPI). The pancreas has many functions. It produces not only insulin, but also various enzymes that provide for the digestion of food. The pancreas can play a significant role in digestive diseases, which is why EPI is sometimes called maldigestion syndrome.
Pancreatic enzymes include amylase, which breaks down starches; lipase, which breaks down fats; and trypsin and chymotrypsin, which break down proteins. The actions of these enzymes are crucial to the digestive process. They allow nutrients from the diet to be absorbed by the cells of the intestine, where they pass into the bloodstream and are transported throughout the body for use by tissues.
As your dog eats, the pancreas gets a signal to release digestive enzymes that travel into the small intestine via the pancreatic duct. Once they reach the center of the intestine, they go to work breaking down food particles. Exocrine pancreatic insufficiency means there is a decrease or lack of digestive enzymes being produced by the pancreas.
Proteins, starches and fats from the diet aren't broken down sufficiently to be absorbed through the intestinal wall. This means nutrients can't get into the bloodstream to supply nourishment to the body's tissues. Much of the food that is eaten remains undigested in the gastrointestinal (GI) tract and ultimately leaves the body in feces.
Signs your dog may be dealing with EPI include weight loss, constant hunger, loose stools that may have a foul odor and contain large quantities of undigested fat, and poor coat condition. Left untreated, a pet with EPI can literally starve to death despite how much food is consumed.
Is Your Dog's Diet the Root Cause of Her Constant Hunger?
Most processed pet food manufacturers load their products up with biologically inappropriate grains, starches and especially fiber, because they know many people assume fiber is healthy, regardless of the type of fiber or who's eating it. The truth is that plant-based ingredients are much cheaper than animal-based ingredients.
Fiber is an especially popular ingredient in weight loss and low-fat dog food formulas, and has also been studied as a potential remedy for annoying canine food-seeking behaviors such as whining, begging, food stealing and trash and dumpster diving.
The argument for extra fiber in pet food is that it makes companion animals feel full, however, your dog's biological requirement for fiber and carbs (starch) is small, which means when fiber replaces protein in the diet, your dog can end up obsessively searching for more amino acids.
In addition, too much fiber can block absorption of necessary nutrients into the small intestine. Excess fiber can create a barrier that prevents antioxidants, vitamins and trace minerals from being absorbed into the GI tract.
While fiber may make your pet feel temporarily full, if it's displacing protein in the diet, she'll remain undernourished at the all-important cellular level. A chronic deficiency of nutrients delivered to the cells of her body can result in feelings of constant hunger. This is a sign your carnivorous dog isn't getting sufficient protein to adequately sustain her biology.
If you feed your dog a nutritionally balanced, species-appropriate, fresh food diet, it's unlikely her food-seeking behavior is the result of malnourishment unless she has an underlying condition that is interfering with her body's ability to properly digest nutrients from her diet.
Helping a Food-Obsessed Dog
If your dog gets a clean bill of health from your vet and he's eating right for his species, there's a good chance the food-seeking is a learned behavior, meaning you've reinforced it often enough that it's now a habit. Tips and tricks for dealing with an always-hungry dog:
- Ignore the begging. You have to stop responding to his begging or he'll never stop begging. In addition, you run the risk of making him overweight with too much food and/or treats.
- Use his food obsession to train him. At least once a day hold short training sessions with your dog. He'll very likely learn new commands and tricks quickly once he realizes snacks are involved. Be sure to use very small portions of healthy treats, for example, frozen peas or tiny squares of cheese.
- Be his food substitute. In other words, distract him as often as possible. Get in some playtime; take him for a nice walk, a ride in the car or a trip to the dog park.
Bottom line: You have to love your dog more than your dog loves food by not giving in to his food-seeking behavior or overfeeding him. The most loving thing you can do is to consistently redirect his energy and focus toward training, exercise, playtime and other nonfood related activities.