Pure fructose is found in fresh fruit, fruit juice and preserves. However, much of it sneaks into the diets though high-fructose corn syrup (HFCS) in soft drinks -- which gets broken down into 55% fructose and 45% glucose in the body -- or via sucrose (ordinary sugar), which is broken down into the same two sugars.
Fears that fructose and HFCS are fuelling the obesity epidemic and triggering insulin resistance and diabetes have been circulating for years, but there have been few direct investigations in humans.