The Wider World

Hippocrates understood heft.

New Years Eve is nearly the midpoint between the two days when Americans eat the most – Thanksgiving and Super Bowl. Hippocrates understood what generally generates girth. It’s worth recalling, as the Bible says essentially the same thing.

This month the Economist delved into why the world is becoming “too big for its own good.”¹ While malnourishment remains a concern mainly in sub-Saharan Africa and South Asia, most of the world’s population is getting wider. The “hubs for blub” are Western countries, Pacific islands and the Middle East. But girths are growing in China as well. Even with devastating famine within living memory, one in four Chinese adults are now obese. Mexico, with unreliable tap water, is the world’s leading guzzler of Coca-Cola. The average Mexican adult consumed 728 servings last year.

In the U.S., the story is achingly familiar. Junk-food calories are often cheaper than healthy ones. Suburban sprawl and the universal availability of food have made the car the new dining room. Two-thirds of American adults are overweight. Alarmingly, 36 percent of adults and 17 percent of children are now obese. If current trends continue, by 2030 nearly half of American adults could be obese. In the wider world, the number of overweight and obese people may double to 3.3 billion by 2030.

The causes are complex. Weight gain rises in line with GDP up to $5,000 per person per year. After that, the correlation ends. Earn more, eat more is the general rule at first. Above the $5,000 threshold, those with higher levels of income and education mostly hold the line on weight gain. In America, obesity rates in children with college-educated parents are less than half the rates of children whose parents lack a high-school degree. As GDP rises, the less well-off become obese in disproportionately large numbers.

In general, greater wealth means people sit more and walk less. As workers earn more, they can afford to eat more food of all kinds, particularly those high in fat and sugar – processed food. Harvard University’s Richard Wrangham says these foods take less energy to break down, so the body absorbs more calories. The amount of food people consume is also influenced by external factors such as the music being played in the background or the serving size. The bigger the bowl of soup, the more of it we slurp.

Genetics is also genius at gaining weight rather than losing it. The body uses a range of hormones known as homeostatic factors to indicate whether it is hungry or full. Ghrelin, made in the stomach, helps to signal that the body wants food. Leptin, a hormone secreted by fatty tissue, tells the brain that it is time to stop eating. When food was prepared in the home, genetics worked in our favor. However, as sugary processed foods – prepared outside the home – have become the norm, genetics works against us.

Sugary food releases dopamine in the brain, signaling pleasure and driving motivation (dopamine is a chemical also involved in drug addiction). As an individual gets fatter, levels of leptin rise so much that the brain seems to stop responding to it. When an individual starts to lose weight, leptin levels drop and the brain signals that he or she is starving, even if he still has plenty of fat to spare. These lower leptin levels explain why, when an overweight individual tries to lose weight, the body works hard to regain it.²

The causes of weight gain are complex but the consequences are appallingly clear. Large girths lower workers’ productivity and in the longer term raise the risk of myriad ailments, including diabetes, heart disease, strokes and some cancers. Being overweight or obese also affects mental health. In America, obesity-related illness accounted for one-fifth of total health-care spending in 2005. These consequences are financially unsustainable. This is where a doctor who lived in the 5th century BC can be of help.

“As a general rule,” Hippocrates wrote, “the constitutions and the habits of a people follow the nature of the land where they live.” Translated, modern men and women of all ages and many cultures did not choose gluttony in the space of the last few decades. Rather, it was more culturally formed, as the Economist notes. “Their surroundings changed dramatically, and with them their behavior.” Simply put, culture is king.

Older Christian traditions understood this. They saw their mandate was to make culture. Described throughout scripture (beginning in Genesis 1:26-28 and 2:15), the church understood its mandate was to make healthy cultures so that humans are healthy. This is how the church primarily loves God and neighbor. Now we see genetics catching up to Genesis. And we see the wisdom of Hippocrates. The habits of a people fundamentally follow the nature – the culture – of the land where they live.

If there is a story that reveals how cultures form appetites, it is the bittersweet history of sugar. Next week we’ll consider it. Near the midpoint between the two days when Americans eat the most, you might end up eating a little less this coming year.

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¹ “The Big Picture” The Economist, December 15, 2012
² “The Caveman’s Curse” The Economist, December 15, 2012