I'm a white American guy who is a longterm resident of Japan, which has one of the world's lowest rates (~8%). When comparing Japan to the US, the three possible factors that stand out to me (anecdotally!) are 1) smaller portion sizes for most meals, 2) lower consumption of sweetened drinks, and 3) the greater use of public tranportation, necessitating more walking in daily life. Of course the disparity could be attributable to some other factors, such as genetics or other social attitudes, but the effectiveness of a system that gets people to eat a little less and move a little more every day seems intituitively plausible.