WE KNOW about good and bad fats. Now suspicion is growing that not all sugars are created equal either. Overweight adults who consume large amounts of fructose have been found to experience alarming changes in body fat and insulin sensitivity that do not occur after eating glucose.

Pure fructose is found in fresh fruit, fruit juice and preserves. But much of it sneaks into our diets though high-fructose corn syrup (HFCS) in soft drinks – which gets broken down into 55 per cent fructose and 45 per cent glucose in the body – or via sucrose (ordinary sugar), which is …