"Scientists would have to develop a more resilient form or discover a chemical that mimics PYY, which is released by the cells lining the intestine, travels through the blood and fools the brain into thinking that the body has been fed."
An interesting experiment, but I'm inclined to agree with the closing statements, which describe weight loss as involving many interlocking systems in the body. I believe the problem with Americans is not that they eat too much -- it's that they eat the wrong stuff, and then they sit on their butts all day instead of burning that stuff off.
Or here's another, less pleasant theory for you: Overweight people are simply breeding faster around here.
This would explain why, against all odds, I am still thin. I've gone for years at a time, eating horrible food and getting almost zero exercise, tethered to a home computer. Then suddenly I'll become an outdoorsman, play frisbee, and enroll in back-to-back weight training courses. From one era to the next, my weight will vary no more than five pounds.
In the parlance of netizens everywhere: WTF?