It comes after the pacific island nations of Micronesia and Tonga, then the United States, where the average adult weighs in at 180.62 pounds (81.93kg).
Samoa ranks as the fourth heaviest nation in the world, then Kuwait sneaks in before Australia at number five.
In Australia, which was once the standard bearer for healthy, active living, an adult weighs on average 170.54 pounds (77.52kg).
The United Kingdom ring in at 10th place, with an average bodyweight of 167.1 pounds (75.95kg).
The study was published in the journal BMC Public Health and launched on Monday at the United Nations conference Rio+20. It highlights the impact of obesity on the nation.
Researchers found overeating shortens people’s lives and leads to a quicker destruction of the environment. The wealthiest countries tend to be the fattest.
While the average body mass globally is 62 kg, north Americans weigh in at 81.9 kg.
The US makes up for only five per cent of the world’s population, yet 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.