The world is getting decidedly fatter. In fact, since 1980 it's gotten twice as fat. Back then a measly 5 percent of men and 8 percent of women were obese. By 2008, 10 percent of men and 16 percent of women were.

This is probably something anybody who has heard of the globally-distributed and oh-so delicious Double Down could have surmised. Sure, the world population is getting fatter, but the more important question is which developed nation is the most overweight. Finally, we have an answer.

The Lancet, a British medical journal, has come out with a series on global obesity today, and the situation looks grim. "The rise of the obesity epidemic seemed to begin almost concurrently in most high-income countries in the 1970s and 1980s; since then, most middle-income and many low-income countries have joined the global surge in obesity prevalence in adults and children," the researchers write in one of their studies. Below, the data collected since 1970 and projected until 2020 is compiled into graph form, and...

...the U.S. is No. 1! We may not be at the top on education anymore, but we've still got the spot for obesity. The graph below just charts nine high- to middle income nations with comprehensive data, though. Another study in The Lancet claims that Pacific Islanders, such as a American Samoa, are in fact the heaviest among the world's populations, according to the Associated Press.

On a more serious note, the obesity epidemic does not seem to be letting up any time soon. For every nation above, the proportion of the population that is overweight is projected to increase until 2020. Though obesity is traditionally thought of as a "First World" problem, it is taking hold in many developing nations. In such low-income countries, obesity first strikes well-off segments of the population before shifting to lower-income groups as these countries become wealthier. Clearly there are still nations too poor to have a substantial obesity problem--the authors note famine-stricken Ethiopia--but such nations are dwindling in number as GDPs rise nearly everywhere. The researchers conclude that governments, which have largely abdicated responsibility for the crisis to individuals and the private sector, need to start taking a more active role in managing their populations' waistlines to avoid a spate of all the well-documented health problems associated with obesity.