But the bridge between America and Canada can be found in an unlikely place: Japan.

DIETS AND DICTA



See, I am solidly in the "American" group when it comes to personal body maintenance - always trying to lose those last 35 pounds - and yet a funny thing happens to me every time I spend a summer or a couple of years in Japan. Within a couple months, I drop to a healthy weight. I begin to look (though not necessarily to dress) like a Canadian. This might be what one would expect, given that Japan has the lowest rate of obesity in the developed world. Books with titles like "Japanese Women Don't Get Fat" may sound smug and condescending, but, as in comedy, there is often truth in smugness.

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.

Americans, of course, would never submit to this sort of violation of personal liberty. Where Japan places an emphasis on enforcing personal responsibility by government or corporate mandate, the U.S. prefers to encourage responsibility by forcing people to live with the negative consequences of their actions. But in this case, it is clear that the two different value systems have led to radically different outcomes in terms of the health of the populace. Japan has succeeded in keeping its people largely thin. America has not.

THE YOGURT RULE



It is time for a rethink of our approach to public health, specifically with regards to obesity. No, it is not possible to use the government to fight fat while adhering to a perfect libertarian ideal; however, it is not possible to do anything while adhering to a perfect libertarian ideal, so let's just start from the notion that we live in a world where outcomes matter along with ideals. I believe that it is possible to change our public health policies in ways that preserve our basic values of personal liberty while significantly improving health outcomes.

One example of such a policy is food labeling. Much is known about which foods contribute to obesity. Added sugar has received much of the attention in recent years, thanks to the work of Robert Lustig. But high fat content is also, fairly obviously, a risk factor for fat. So here's an idea: Let's force high-sugar and high-fat foods to be labeled with the sentence "This food contributes to obesity," while putting an opposite label on fresh foods, vegetables, etc. Large, visible, color-coded labels in grocery stores will allow people to make informed choices quickly and easily. Along similar lines, high-sugar and high-fat foods should be labeled "not healthy for children," so that parents - who probably don't want to be saddled with an obese child - can avoid these foods.