“Scientists have known for decades that the body can make fructose. A special biological process known as the polyol pathway first converts glucose to a substance known as sorbitol,* then further converts the sorbitol to fructose. But while the polyol pathway is well known, it is generally thought to be minimally active in most people, such that it produced an inconsequential amount of fructose.”

Richard Johnson and David Perlmutter, Nature Wants Us to Be Fat