Different metabolic tolerances explain why certain human foods can be deadly for dogs, according to a Las Vegas Review-Journal article.

In the article, Dr. David Henderson warns of foods that are especially toxic to dogs because they detoxify foods differently than humans. Xylitol, a popular sweetener in gum and candy, can cause fatal hypoglycemia if ingested by dogs.

"The (dog's) body processes it as sugar so there's an insulin surge, but there's no sugar there for the cells to uptake," Henderson said. "It's like an insulin overdose."

Henderson said that in addition to the choking hazard of bones, corncobs and foods with pits, dogs cannot digested these foods, which can splinter and become lodged in the intestines. Dogs should not consume grapes or raisins due to potential kidney failure, as well as anything with onions because the disulfides in them destroy a dog's red blood cells.