The pacific island nations of Micronesia and Tonga are at the top of the league table, followed closely by the United States where the average adult weighs 180.62 pounds (81.93 kg).
The United Kingdom is the tenth fattest country in the world, where an average adult weighs 167.1 pounds (75.8 kg).
The study, published in the journal BMC Public Health and launched on Monday at the United Nations conference Rio+20, highlights the problem of obesity in relation to the environment.
Excess consumption shortens people's lives and accelerates the destruction of the environment, and is concentrated in richer countries.
While the average body mass globally was 62 kg, North Americans weigh in at 81.9 kg.
And while the US makes up only five per cent of the world's population, it accounts for almost a third of the world’s weight due to obesity.
In comparison, Asia has 61 per cent of the world’s people but only 13 per cent of the world’s weight.