From Nordic to Japanese to Mediterranean, a number of diets claim to have the key to longevity. But what do these really have in common?

What do Japan, Greece, Italy, Norway, France, Germany, and Canada have in common? You might be scratching your head for a while, so here's the answer. They are among the most equal nations on Earth, and they also happen to have the longest average life spans. Could these two factors be connected somehow? Keith Payne of Inequality.org thinks so.

In an article titled "Forget the Nordic Diet. Try the Nordic Tax Plan," Payne argues that we're chasing the wrong carrot when it comes to pursuing optimal health and longevity. We've bought into the notion that a geographically-determined fad diet holds the secret to health, but in fact, fretting about eating more olive oil, lingonberries, fatty fish, or red wine is missing the point. Payne writes:

"Medical evidence suggests that differences in lifespans across countries are better explained by social conditions than diet. Researchers have found that among economically developed countries, income inequality is a major predictor of longevity."

These countries that have given rise to such enormously popular fad diets -- the Mediterranean diet, Nordic diet, Japanese diet, and so on -- do not follow the same rules. Nor does anyone really know what to make of Canada and Germany's foods, with their gravy-slathered poutines, relatively few seasonal vegetables, breaded schnitzel and beer. But when you look at social factors in these nations -- and the economic policies designed to reduce inequality -- the connection becomes clearer.

"If social equality is really the active ingredient keeping people healthy in these countries, then other mysteries start to make sense. Germany and Canada have low inequality and accordingly, long lives. France is no longer a paradox [referring to high levels of saturated fat]: Their low inequality explains their longevity. The Bordeaux might have nothing to do with it."



The problem is, it's far more challenging to overhaul health care and the education system and to offer a living wage than it is to sell a fad diet to the world. But if governments are serious about improving their citizens' quality of life, then that's precisely what they should do.