An Urban's Rural View

In the debate over obesity, some people pooh-pooh the role of sugar. The real secret to controlling weight and combating obesity, these folks think, is counting calories. Consume fewer calories than you burn and you'll lose weight.

And, some of these folks say, you can take your calories in a balanced diet that includes fruits and vegetables and whole grains OR you can take them in cheeseburgers or chocolate cake. Just don't exceed your daily limit. A calorie is a calorie is a calorie.

Why, the other morning on CNBC I heard no less a nutrition expert than Warren Buffet say this. As he fielded questions on his company's investments, the Oracle of Omaha sipped a cherry Coke and nibbled Oreo cookies. He's fine, he said, as long as he doesn't exceed 2,700 or 2,800 calories a day.

The anti-sugar types may be forgiven for suspecting Buffet's holdings of Coca-Cola stock affect his dietary judgment. In any event, to these people, all calories are not created equal. Too much sugar, they argue, can of itself cause obesity. And because obesity inflates society's health-care bill, they support measures aimed at reining in sugar consumption, like soda taxes.

And now there's a new study (http://tiny.cc/…) blaming sugar for a higher incidence of diabetes even if it doesn't always cause obesity.

Diabetes, the study's authors say, has doubled world wide in the last three decades. With obesity expanding during those same decades, it's tempting to link the two.

But as the study notes, there are countries that have a lot of diabetes and little obesity -- countries as diverse as France, the Philippines, Bangladesh, Romania and Georgia. To determine why, the study compared the availability of sugar and the incidence of diabetes in 175 countries over the last decade.

Controlling for other possible explanations and crunching equations mightily, the study's authors concluded that sugar was indeed the culprit. For each increase of 150 kilocalories per person per day of sugar availability -- the equivalent of a 12-ounce soft drink -- they found a 1.1% increase in diabetes. By comparison, for an increase of 150 total kilocalories per person per day they found only an insignificant 0.1% rise in diabetes.

Or, as New York Times blogger Mark Bittman summarized the study's conclusion (http://tiny.cc/…), "It isn't simply overeating that can make you sick; it's overeating sugar. We finally have the proof we need for a verdict: sugar is toxic."

Bittman argues the study's methodology is impeccable, "the closest thing to causation and a smoking gun that we will see," demonstrating sugar's guilt "with the same level of confidence that linked cigarettes and lung cancer in the 1960s."

He may be right. I have no stake in defending sugar; I'm prepared to believe it causes diabetes. I'm not competent to question the methodology; I am prepared to believe the study was conducted to the highest standards.

But I'm not sure the study is the last word Bittman says it is. If I had to guess, I'd say the challenges to it will emanate from that old, informal principle of statistics: Garbage in, garbage out. How accurate is the United Nations Food and Agriculture Organization "availability of sugar" data the authors used? Do we really know how much sugar is "available" in Bangladesh? Similarly, how good are the countries' reports on diabetes?

We'll see. Meanwhile, if there's any solace in the study for corn growers, it's that, in Bittman's words, "The study found no significant difference in results between those countries that rely more heavily on high-fructose corn syrup and those that rely primarily on cane sugar."

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