Why are the Japanese so slender? There are three reasons, and none of them has to do with genetics. One is the traditional Japanese diet, which is heavy on fish, vegetables, and rice. The second is Japan’s mass-transit-centered urban design, which encourages Japanese people to walk a lot more than Americans. But the third factor is paternalism. Japan’s government takes an active role in combating any hint of an upward trend in fatness.

In 2008, Japan’s diet passed a law designed to combat “metabolic syndrome,” which is known to Americans as “pre-diabetes.” The so-called “Metabo Law” requires overweight individuals, or individuals who show signs of weight-related illnesses, to go to dieting classes. If they fail to attend the classes, the companies that employ them and/or the local governments of the areas in which they live must pay fines to the federal government. In addition, companies with more than a certain percentage of overweight employees are fined directly.