Some scientists believe that Pacific island populations have evolved to maintain their larger build — a concept known as the “Thrifty Gene” hypothesis. For this region of the world, the concept is based on the fact Pacific islanders once endured long journeys at sea and those who fared best stored enough energy in the form of fat to survive their journey.

“We have the remnants of those people … and their metabolism as well,” says Waqanivalu. The increased risk of obesity among native Pacific islanders is shown on the islands of Fiji, where the population has a more mixed ethnicity. The country stands at the lower end of the region’s spectrum with 36.4% of the adult population classed as obese. Just more than half of the Fijian population are native iTaukei, with the remainder mostly of Indian origin, according to the CIA World Factbook. “That explains the lower rates,” says Waqanivalu.