The short answer: It is not recommended.
The long answer: A common cooking condiment, sugar is a sweet-tasting soluble carbohydrate that is composed of glucose and fructose. Though it is safe for humans to eat, it’s not advisable for your canine companion to consume it. Excessive amounts of sugar can lead to health complications such as stomach troubles, inflammation, and obesity. Sugar can upset the balance of bacteria found in your dog’s gut, causing vomiting or diarrhea. It also triggers metabolic changes in your pet’s body, leading to weight gain, diabetes, and/or dental cavities, especially if your dog’s teeth aren’t brushed properly after he consumes sugary food.
Another more harmful substance related to sugar is the artificial sweetener called xylitol. This is often created from corn fiber, birch trees, hardwood trees, and other vegetable materials and used as a sugar substitute for food such as bread, candy, peanut butter, and gum. It stimulates the release of insulin, dangerously dropping your dog’s sugar levels and causing rapid liver failure. Xylitol poisoning can happen as fast as 30 minutes to an hour after your dog has consumed it.
What to do if your dog accidentally eats sugar or xylitol: Keep an eye on your dog for any changes in his behaviour and mood. Call your veterinarian if your dog starts to vomit, experiences the runs, or gets a stomach ache.
If you suspect that your dog accidentally ate food containing xylitol, watch for vomiting and symptoms of hypoglycemia (low blood sugar): collapsing, lethargy, inability to control movements, and seizures. Liver failure can occur within a few days.
In summary: Sugar is not a necessary part of your dog’s diet. You can choose to reward him with healthier, dog-friendly treats such as fruits and vegetables that don’t contain high amounts of sugar. Also, be careful in feeding him baked goods or treats that have xylitol in them. This sweetener can cause irreparable damage to his body.