Study: America Is Officially the Fattest Developed Country in the World Study: America Is Officially the Fattest Developed Country in the World Source: healthland.time.com If you tuned into the season premier of the Biggest Loser last night — during which the reality show’s trainers Bob Harper and Jillian Michaels toured the country collecting obese people — you got the message: Americans are drowning in fat. By arZan ... View all of arZan's posts.