Fructose is a form of sugar found naturally in fruits and vegetables. It’s also a component of refined table sugar, or sucrose, which is half glucose and half fructose, and of high fructose corn syrup (HFCS), which has a ratio of 55% fructose to 42% glucose.When it was discovered that fructose, unlike glucose, didn’t raise blood sugar levels or insulin and was significantly sweeter than glucose, it was hailed as a boon to all diabetics who could now satisfy a sweet tooth with impunity.But then a dark side of fructose came to light. Scientists discovered that while the body can handle reasonable amounts of fructose from fruits and vegetables without serum fructose concentrations rising to dangerous levels, it can be overwhelmed by large quantities of fructose, especially refined (man-made) fructose. Unfortunately, our steadily increasing consumption of refined sugar and HFCS seems to have done just that.In the 19th century, average refined sugar consumption was about 7 pounds per year p…