Back in 1990, ten states in the USA had an obesity prevalence of less than 10%. Among the remaining states, nowhere did obesity exceed 15%. A mere 20 years later and not a single state had a prevalence of less than 20%. Meanwhile, obesity in a dozen southern states had risen to more than 30%. What happened?

中文翻译：

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健康不平等的政治

早在1990年，美国的十个州的肥胖症患病率不到10％。在其余各州中，肥胖率均未超过15％。仅仅20年后，没有一个州的患病率低于20％。同时，南部十二个州的肥胖率已上升到30％以上。发生了什么？