There is a big trouble in the faraway Polynesian Kingdom of Tonga. Until recently Tonga was best known for the skill of its rugby players but today Tonga has been classified as "the most obese nation on earth", caused by a reliance on imports of cheap fatty meats, refined carbohydrates and other packaged junk foods. Traditionally, Tongans ate a lot of fish and root vegetables, but their eating patterns have changed drastically. Obesity has led to a great number of Tongans developing deadly Type 2 diabetes. Amputations and heart disease have hit record levels and life expectancy is falling. We investigate Tonga's efforts to combat this medical emergency and explore why there is "Big Trouble in Paradise".