He made an amazing discovery while going through scientific journals for a book he was writing called The Slow Poisoning of America. In hundreds of studies around the world, scientists were creating obese mice and rats to use in diet or diabetes test studies.
No strain of rat or mice is naturally obese, so the scientists have to create them. They make these morbidly obese creatures by injecting them with a chemical when they are first born. The Mono-Sodium-Glutamat (Natrium Glutamat) triples the amount of insulin the pancreas creates, causing rats (and humans?) to become obese They even have a title for the race of fat rodents they create: "MSG-Treated Rats" .