The biology behind this flight or fight action, triggered by the body's age-old quest for fat/energy balance, is now coming to light. In the journal Nature, Dr. Zofia Zukowska of Georgetown and her colleagues fed a group of mice a fast food-like diet high in fat and sugar, while feeding another group normal diets. When the half of each group of mice were also stressed by being caged with an aggressive mate, those hat were fed a MacMouse diet AND had the ill fortune of rooming with a bully accumulated twice as much belly fat in two weeks as rodents that were not stressed. Over three months, the fast food-fed, stressed mice became grossly obese.

Poignantly, Zukowska's team found that they could reverse the fat buildup by implanting a slow-release tablet of a small molecule that blocks the cellular receptor for NPY.

The findings parallel those of neuroscientist Mary Boggiano, who got rats to binge on Oreo cookies by subjecting the rodents to a regimen of three components:

1. a diet
2. breaking the diet as the animals gained back lost weight
3. shocking the rodents' feet (another source of stress).

The animals began to binge after three cycles of diet-refeeding-stress. In fact, their craving was so strong, the dieted-refed-stressed mice would forego their normal chow, even if it was positioned nearby in their cage, and run down a gauntlet of foot shocks to gobble down the Oreo cookies lying at the other end. She found that the bingeiing rodents were churning out high levels of NPY, PYY, acting on a brain receptor that mediates appetite. And the pathway linked into centers of the brain responsible for addiction to drugs such as cocaine.

Thus, she showed the same NPY pathway works to cause binge eating after dieting and high fat/sugar foods--the kind of food behavior that leads to bulimia and binge eating disorders in humans. And that this is more about addiction than lack of willpower.

What the studies suggest is that we cannot point our fingers at fast food conglomerates and the typically poor American diet as the SOLE causes of our current epidemic of obesity. Our over-stressed lifestyles also make a contribution. Dieting leads to food craving. Satisfying that craving with fatty/sugary foods counteracts the weight loss effects of dieting. And now we have just learned that adding in long-term stress creates an even bigger problem: eating disorders, especially those involving binge eating and obesity.

As I found during the research of my book "Lying in Weight: the Hidden Epidemic of Eating Disorders in Adult Women" (Harper Collins, May 2007), chronic stress coincides with specific life transitions, such as marriage, pregnancy, parenting, mid and late life. These transitions move a person who is merely experimenting with food issues and behaviors like dieting, overexercising and chewing and spitting out food into full-blown and potentially life-wrecking eating disorders.

So now that Zukowska's team has given us more evidence about the stress-diet-eating disorder connection, what do we do?

The answer today is to search for a quick fix through a drug. Not surprisingly, the news is abuzz with a possible anti-obesity drug fashioned from the small molecule that could reverse the fat-buildup in mice.

But the answer is more complex than drugs. We hate to hear it, but here's the truth: we need to take a serious look to the kind of foods we are eating, in what quantity we eat them, AND how we are going to get a handle on the over-stressed lives we are living.