Eating to Live or Living to Eat?

Those reactions quickly drown out the subtle signals from the stomach that are saying, in effect, "Still digesting down here. Don't send more!" Social cues add pressure and permission to indulge. Soon, everybody is having a slice—or two.

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.Breitling Cosmonaute

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.
Two Reactions to Cake
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Two conferences this week on obesity are each examining aspects of how appetite works in the brain and why some people ignore their built-in fullness signals. Scientists hope that breakthroughs will lead to ways to retrain people's thinking about food or weight-loss drugs that can target certain brain areas.

In a study presented this week at the International Conference on Obesity in Stockholm, researchers from Columbia University in New York showed pictures of cake, pies, french fries and other high-calorie foods to 10 obese women and 10 non-obese women and monitored their brain reactions on fMRI scans. In the obese women, the images triggered a strong response in the ventral tegmental area (VTA), a tiny spot in the midbrain where dopamine, the "desire chemical," is released. The images also activated the ventral pallidum, a part of the brain involved in planning to do something rewarding.Rolex GMT Watches

"When obese people see high-calorie foods, a widespread network of brain areas involved in reward, attention, emotion, memory and motor planning is activated, and all the areas talk to each other, making it hard for them to resist," says Susan Carnell, a research psychologist at the New York Obesity Research Center at Saint-Luke's-Roosevelt Hospital and Columbia University and one of the investigators.