Before you write another one of these, with all respect in the world, kindly read Dr Robert Lustig's recent blockbuster Metabolical. I'd be very surprised if that book doesn't answer most if not all of your questions. then I would go back and read his first two. it's an investment in understanding the obesity epidemic and a great deal more. It's not environmental toxins alone. It's a lot more than that and we have allowed it to happen. It's called profit motive. Worth the read.