Obesity is a growing global concern. Data suggests the number of obese people in the world has tripled since 1975 to approximately 2.1 billion—roughly 30% of the total population—and this number continues to rise.
Obesity is one of the leading causes of preventable death, dramatically decreasing not just a person's overall quality of life but also their life expectancy. Obesity puts people at higher risk for diabetes, heart disease, and even certain types of cancer. Additional health risks from diabetes include osteoarthritis, sleep apnea, kidney disease, strokes, and high blood pressure. Pregnant women who are obese may suffer from complications that can lead to health problems for the mother or child.
Because of the many health concerns associated with obesity, it can be used as a major overall health indicator of a population. The healthiest countries in the world generally have lower obesity rates.
One frequently used measure of obesity all over the world is Body Mass Index, or BMI. Introduced in the 1830s, this measure considers a person's weight in relation to their height. A normal BMI is 18.5 to 24.9, and a BMI of 30 or higher is considered obese.
Despite its popularity, BMI is widely considered to be a flawed metric. It fails to consider vital influencing factors such as body type, gender, age, and bone density. Moreover, BMI can't distinguish between muscle and fat.
This can lead to clearly inaccurate results, particularly in athletes. For example, professional wrestler "Stone Cold" Steve Austin in his prime was a heavily muscled picture of physical fitness—but his 6'2" height and 252-lb (114kg) weight gave him a BMI of 32.4, classifying him as obese.
Because of results such as these, BMI is a fairly imprecise determiner of whether or not a given person is overweight. However, because of its global ubiquity, it remains the best currently available metric to use for country-to-country comparisons.
A newer, but notably more consistent test for obesity is waist-to-height ratio, or WHtR. According to WHtR, a person is obese if the circumference of their waist measures more than half their height. Thus, a WHtR of .5 or lower is healthy, and a WHtR of higher than .5 is obese (though the cutoff rises to .6 for patients aged 50 and older).
National obesity is typically measured by examining either the average BMI of its citizens or the percentage of citizens whose BMI qualifies as obese. These methods give similar, but different results. For example, the World Health Organization's 2016 data yields the following results:
*For the complete list of all countries, see the table below.
While it's easy to assume that the easy availability of rich, decadent foods in the world's wealthiest and most developed countries would make them the most obese, this isn't always the case. The United States and the United Kingdom are two of the most economically rich and developed countries globally. However, they'd place 18th and 48th respectively when ranked by BMI, and 123rd and 95th when ranked by percentage of obese adults.
Oceania seems to be especially challenged by obesity. One proposed cause is that foreigners taught the locals to fry their meals, abandoning their traditional cultivation, preparation, and preserving skills. Other possible factors include genetic predisposition; an increased tendency to replace local food sources with less nutritious imported options; and the rise of fast-food restaurants, which have replaced healthier local food (a scenario mirrored in Kuwait).
Additionally, the World Health Organization posits that the rising costs of healthy food and increased food scarcity in underdeveloped nations is a contributing factor to obesity in poor and/or developing nations and least developed nations.
Here are the 10 most obese countries by obesity rate:
Nauru has the highest obesity rate in the world, with a 61% obesity rate.