Blood sugar. (Note from a Worldwatcher).

Is there any strong link, either for individual humans or for whole societies, between physical health and mental health? Overwhelming evidence says yes. For one thing, as any psychopharmacologist can attest, mental illness is often associated with specific physical conditions--depleted neurotransmitters, or excessive spiking of blood sugar. If your nerves and hormones are out of whack, your attitudes and behavior are more at risk of deteriorating.

What, then, about a possible connection between physical fitness and mental fitness? Are flabby populations more likely to fall into flabby habits of thinking and reacting? Here the connection may be less obvious. To begin with, it's not so clear what mental fitness is. But here, too, the best available evidence now says there is a rather strong correlation between a robust body and a robust mind. Around two decades ago, many organizations began investing in corporate fitness programs because they had seen convincing evidence that physically fit employees are more productive. Aerobic exercise, it turns out, makes people not only less prone to heart attacks; it increases their stamina, oxygenates their brains, sharpens their senses, and heightens capacity to cope with stress.

It should be a matter of serious concern, then, when a nation finds that unprecedented numbers of its citizens are unfit and obese. Americans are the world's largest consumers not only of the planet's declining natural resources, but of its growing output of sugar and fat. If there's really a connection between physical and mental well-being, there's fair reason to believe that Americans--along with many Europeans and others--have grown soft.

In the aftermath of September 11, that softness could be costly. Many people seem to have fallen into a habit of equating "toughness" with having the technological capacity to wield heavy vehicles and weapons. But real toughness means having the cognitive sharpness to think through difficult challenges, and the patience and resilience to handle heavy stress. It means being able to exercise independent judgement rather than simply making easy substitutions of faith for education, or doctrine for discovery. It means being able to negotiate the risks of life, along with its wonders, without retreating into compulsive escapism and consumption.

Whether deliberately or not, the terrorists could hardly have picked a more devastating moment to attack. The U.S. economy was already weakening, and the credo of the current U.S. administration is to respond to economic weakness by encouraging greater consumption--no distinction being offered between those kinds of consumption that build strength and those that further weaken. With the aftershock of the attacks threatening to plunge the nation into an economic abyss last fall, the government's advice to the people was, as New York mayor Rudy Giuliani put it, to "go shopping."

As it happened, that period was also the beginning of the Christmas shopping season, prelude to a one-time religious holiday that has transmogrified into a month-long orgy of commercial consumption. Every year, December becomes the measure of whether America's economic year has been a success. When sales last December were lower than usual, Associated Press reporter Frank Green called it the "worst holiday shopping season in a decade." The year before, sales were "good." He and a thousand other news reporters seemed not to notice the journalistic inappropriateness of automatically attaching the ideologically weighted adjective "good" to an economic trend that not all economists think is good (see Herman Daly's Steady State Economics, for example).

As a result, the U.S. government's response to the terrorists and its response to the longer-term economic slump became mindlessly conflated in the form of an explicit exhortation from the Bush administration to forego saving or investing, and to go out and consume. Two U.S. congressmen, Republican representatives John E. Peterson and Mark Kennedy, promptly had themselves photographed filling their mouths at a McDonald's.

In the photo, those congressmen's cheeks bulged like a couple of cowboys' holsters, and both men seemed more intent on Sending a Message to the world than in enjoying their Happy Meal. I'm sure they weren't alone. With Osama still nowhere in sight, Americans were consumed with their aching--and aching to consume.

What didn't quite come through in that picture is that if gorging is not good for individual humans, it's not good for the country they live in, either--or for the world whose health that country depends on.