eat to live (and vice versa)

From Melinda Beck in the WSJ...

Beck also provides a "power-of-food" scale/test so you can see how you stack up!

Scholars have understood the different motives for eating as far back as Socrates, who counseled, "Thou shouldst eat to live, not live to eat." But nowadays, scientists are using sophisticated brain-imaging technology to understand how the lure of delicious food can overwhelm the body's built-in mechanism to regulate hunger and fullness, what's called "hedonic" versus "homeostatic" eating.

One thing is clear: Obese people react much more hedonistically to sweet, fat-laden food in the pleasure and reward circuits of the brain than healthy-weight people do. Simply seeing pictures of tempting food can light up the pleasure-seeking areas of obese peoples' brains....

The overweight subjects had strong reactions to the food in the amygdala—the emotional center of the brain—whether they were hungry or not. The healthy-weight subjects showed an amygdala response only when they were hungry....

All these findings beg the question, which came first? Does obesity disrupt the action of leptin, or does a malfunction in leptin signaling make people obese?

Similarly, are some people obese because their brains overreact to tempting food, or do their brains react that way because something else is driving them to overeat? Researchers at Yale and elsewhere are turning to such questions next....

Curiously, several studies have shown that some forms of gastric bypass surgery can actually create changes in the brains of formerly obese people —and not just because their stomachs are smaller and fill up more quickly. Levels of leptin and glucose tend to drop in bypass patients, ending diabetes for many of them....

In another study, 17 people who had successfully lost weight had more activity in the dorsal lateral prefrontal cortex, a part of the brain involved in impulse-control in response to food than people who were still obese. In short, successful weight losers seemed to have having second thoughts about eating on impulse...