I was looking up some data on obesity rates, mostly for American states, and I stumbled onto the maps below on obesity rates by nation for males & females (in that order):
You can find the source and legend here. In any case I was totally surprised at how fat Arabs are, particularly Gulf Arabs. They aren't in the NationMaster data set so I had never encountered any numbers on obesity. And the Gulf Arabs I've met in my life didn't strike me as disproportionately obese. But in hindsight I think I have an explanation: most of the Gulf Arabs I've met are upper or upper middle class males who have come to the United States to complete their educations. In affluent societies there tends to be a negative correlation between obesity and socioeconomic status. If the only image of Americans that foreigners had were of people from Manhattan it would be a different image altogether. The obesity rates among women are striking, and in hindsight not too surprising. In the pre-modern situation women did do work, and in places like the Hejaz they still engage in many public activities in contravention of national norms imposed from the elites of the Nejd. But female labor is not longer necessary in an affluent society whose wealth is not due to labor productivity. Here's an article on forces inside Saudi Arabia trying to block female fitness for the usual reasons.