Here's the first link from Google searching for "life expectancy obesity generation":
http://www.fitfaq.com/2005/02/obesit...t-us-life.html
It's by no means certain, it's damn near impossible to predict things of that nature. Other advances could reduce the death rates of heart disease and diabetes and balance everything out. Maybe people will get the message and get off their fat asses. But if things continue as they do, it's not gonna be pretty.
Here's another, from the UK:
http://observer.guardian.co.uk/child...081215,00.html