Cause of the obesity epidemic discovered?

There is an obesity epidemic in the Western world, and it starts in childhood. Strangely, it isn't directly linked to affluence with children from poorer backgrounds more likely to be obese than children from wealthy families.

Now a Professor of Pediatric Endocrinology at the University of California claims that a major cause is the widespread use of fructose in processed food. In an interview on ABC's Radio National he explained why. Fructose is metabolised in a different way to glucose, triggering high levels of insulin which result in sugar being taken out of the blood stream and converted to fat. The result: we feel hungry again (low blood sugar) and get fatter.

Fructose is being poured into a huge range of processed foods. In fact our fructose consumption has gone from less than half a pound per year in 1970 to 56 pounds per year in 2003. Want a fast-food burger? That bun is full of fructose. We were never designed to eat fructose in this processed form. Fructose is OK in fruit, when it is accompanied by lots of fibre.

One result of all this fructose is that we keep feeling hungry and so we buy more. Good news for the food companies.

The big question is - do the food companies know about this? And if so, what are they going to do about it?