The tiny Pacific island nation of Nauru holds that honor. At only 8.1 sq. miles, with a population of less than 10,000, the country's inhabitants have virtually become giants.
Ninety-five percent of the island's adult population is overweight, and 85 percent of the male adult population is obese, according to ABC News.
However, island natives haven't always been this fat. According to ABC, it wasn't until they began importing Western food that the population's size exploded. Now half of Nauruans suffer from Type II diabetes.