Due to differences with sampling methods and time periods, it is rather difficult to directly compare obesity rates in different countries so any numbers mentioned in this article are best-guess estimates.
According to the WHO Global Database on BMI, the small Micronesian island of Nauru has the highest obesity rate (BMI>30) with a massive 78.5% of adults falling into this category. Incidentally, Nauru also has the highest rate of diabetes in the world. Pacific Island nations are over-represented in obesity statistics with the 6 most obese countries coming from this region.
The United States is currently the 9th fattest nation in the world and if current trends continue, it will likely find itself in the top 5 by 2020. In the early 1990s, the obesity rate in the USA was just 12% however this has almost tripled to 33.9%.
Increases in obesity rates are primarily due to urbanization, which has caused a shift away from jobs in the agricultural sector, where a large amount of physical labour is required, to jobs in the service sector which are typically sedentary. Dietary changes are also a significant contributor to the obesity epidemic. As countries become more “Westernized”, they tend to consume more fat through meat and dairy products, which are relatively scarce items in less developed countries, they also consume less fiber, and more refined, calorie dense foods. As a result, calorie intakes are around 50% higher in developed countries compared to developing countries. In Sudan for example, the average calorie intake per day is 2,260 kcal compared to 3,754 kcal in the USA.
The table below shows the 20 most obese countries in the world.
|United States Of America||33.9||66.9|
|United Arab Emirates||33.7||-|
Source: World Health Organization: Global Database on Body Mass Index http://apps.who.int/bmi/index.jsp
It is even more difficult to determine the least obese countries in the world because statistics for many African countries, who would be expected to be among the least obese, are not available. According to WHO statistics, the least obese country in the world is Vietnam with just 0.5% of adults considered to be obese. India, Laos, Madagascar, Gambia, Indonesia, and China also have very low obesity rates of less than 3%.