6 Reasons Why Your Dog Shouldn’t Have Sugar

PetMD Editorial
Written by:
PetMD Editorial
Published: September 19, 2016
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Reasons Why Your Dog Shouldn’t Have Sugar

By Teresa Traverse


As much we enjoy eating sugary treats like ice cream and candy, they shouldn’t be fed to dogs. Although it is a necessary component of their diets, certain sugars, like those found in sweets, can be harmful to dogs just like it is to people.


“Dogs need sugar of some sort. They need carbohydrates [which are broken down into sugar or glucose by the body] to live and operate. We just don’t need to be giving them candy since there’s no real added value,” says John Faught, DVM and medical director of the Firehouse Animal Health Center in Austin, Texas. “Excessive amounts causes inflammation all throughout the body, and it’s just not necessary.”


From tummy troubles to obesity, here are the reasons your dog shouldn’t have sugar. 

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Upset Stomach

If you want to avoid having to clean up vomit or diarrhea, it’s probably best to avoid giving your dog sugar.


“In the short term, a sugary treat can lead to an upset stomach,” says Ari Zabell, DVM DABVP and senior director of client experience and advocacy at Portland, Oregon-based Banfield Pet Hospital. “All animals rely on the bacteria and other microorganisms in our gut to help us digest the food we eat. A higher dose of sugar than our pets are used to can upset the balance of those micro-organisms and lead to diarrhea – sometimes explosive, sometimes bloody, and sometimes even with vomiting.”

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Both chocolate and the artificial sweetener xylitol—found in many sugar-free candies—can be toxic to dogs.


“Chocolate contains theobromine, a substance that can be poisonous to your pet. Dark, semi-sweet and Baker's chocolate can be lethal if ingested,” says Zabell.


Dogs can’t digest theobromine as efficiently as humans. Theobromine can be used medically as a diuretic, heart stimulant, blood vessel dilator, and a smooth muscle relaxant. Since dogs can’t process theobromine, excessive amounts of it can cause vomiting, diarrhea, increased thirst, panting or restlessness, excessive urination, a racing heart rate, muscle spasms and occasionally seizures, according to Shelby Neely, VMD.


“[Xylitol] can cause a life-threatening blood sugar drop or hypoglycemia in dogs. Additionally, xylitol can also cause rapid liver failure,” says Heather Loenser, DVM, and veterinary advisor, public and professional affairs, for the American Animal Hospital Association. “Dogs are most often exposed to xylitol when they accidentally eat sugar-free gum or peanut butter that contains it. I recommend that dog owners carefully read the label of all ‘sweet’ products including tooth paste, cookies and candies, and keep anything containing xylitol out of reach of a curious canine.”

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Another downside of consuming too much sugar? Dental caries or cavities.


“The problem with sugar is that bacteria in the mouth use it which produces acids.  Acids increase the loss of minerals in the enamel or the outer coating of the teeth, leading to dental disease,” says Neely. “You can’t avoid sugar – pretty much everything you can put in your dog’s mouth contains some form of sugar to some degree.  The best you can do is feed dog foods that are lower in carbohydrates and brush your dog’s teeth.  It is also essential that your dog’s teeth be checked at least annually by your veterinarian and that you agree to professional cleanings as recommended by your vet.”

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Weight Gain

Refined sugar is largely empty calories. If you’re constantly giving your dog sugar, they can gain weight, which can stress joints and lead to other problems down the road.


“Heart disease, joint problems, lethargy, and difficulty breathing from the additional weight on the chest wall are just a few of the other problems that can result. In general, even if your pet avoids these diseases for a while, quality of life is decreased (less energy, less interest in playing, etc.) when he is overweight,” says Neely.


Obesity is sadly a growing problem in pets, and it can lead to other harmful conditions.


“Obesity is very common in dogs,” says Zabell. “One in four of the dogs we see at Banfield Pet Hospital is obese. Obesity in dogs has been linked to other serious conditions including arthritis, heart and respiratory problems and diabetes.”

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Metabolic Changes

Sugar causes increased secretion of insulin, which the body needs to store and use sugar, Zabell said. Insulin has many effects on other hormones in the body, which can change a pet’s muscle tone, fat storage, immune system and energy levels. These changes can lead to weaker, less active and obese pets who are more susceptible to other hormone related diseases, infections and obesity, he added.


“In the long term, sugar can cause some significant changes to your pet’s body and metabolism – similar to people, the most common challenges we see along these lines are obesity and diabetes – and sadly, both of these diseases come with their own list of problems which can be made worse by sugar,” Zabell said.

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If your dog continues to gain weight, there’s a chance he or she could develop Type II diabetes. Dogs who have this condition can’t process sugar because their pancreases either doesn’t produce insulin or makes very little. Insulin is a hormone produced in the pancreas that regulates the amount of glucose or sugar in the blood.


"Excess sugar leads to excess insulin production which can lead to cells becoming nonreactive to the insulin, which can lead to exhaustion of the insulin producing pancreatic cells resulting in high sugar in the blood,” says Neely.