Dogs like sweets as much as humans do, but sugar and artificial sweeteners like Aspartame can be harmful. It may be time to add fructose to that list, at least in large quantities. Also called fruit sugar, fructose occurs naturally in fruit but is mostly found in the refined sugars and high-fructose corn syrup used to make breakfast cereals, pastries, soda and fruit drinks, and other sweet foods.

Too much fructose in the diet may be contributing to liver and heart disease in humans, reports the September 2011 issue of the Harvard Heart Letter. Liver cells are the only ones in the body that metabolize fructose. Fat is a key by-product of the breakdown of fructose. Give the liver enough fructose, and tiny fat droplets begin to accumulate in the organ. This build-up is called non-alcoholic fatty liver disease and over the long term may cause serious liver damage. If too much fructose is bad for us, it’s probably not good for dogs either.