Stress and Your Waistline: Gaining Belly Fat May Be Body's Way of Coping

Stress may be making you fat.

There's growing evidence that chronic stress can make you thick around the middle. Studies in rats and monkeys clearly show that a high-stress environment increases risk for accumulating abdominal fat, the type of fat linked with heart disease. And in human studies, stress appears to put normal-weight women at higher risk for excess belly fat.

While the evidence is strong that stress may contribute to weight problems, exactly why and how it happens isn't clear. Even so, a number of firms have used the link between stress and belly fat to tout pills that claim to lower stress hormones and help people lose weight. Researchers say there's no evidence such pills work. Claims by makers of pills such as CortiSlim and Relacore have recently drawn the ire of federal regulators.

To be sure, people gain weight because they consume more calories than they burn. But chronic stress may complicate the equation, causing fat to accumulate around the middle and prompting eaters to choose less-healthful foods.

This month, a report in the medical journal Brain, Behavior and Immunity looked at the link between stress and the consumption of comfort foods, finding that there may be a physiological reason people tend to binge on fatty and sugar-laden foods during times of stress. In a series of rat studies, researchers at University of California-San Francisco fed two groups of rats a diet of rat chow and sugar water. But one group of rats lived more stressful lives, spending short periods of time during the day in a confined space. Stress hormone levels were higher in the confined rats, and the stressed rats started to eat less healthy chow and gulp down more sugar water.

But what happened next was surprising. As the stressed-out rats started to accumulate more belly fat, their stress hormones went back down. The higher the belly fat, the lower the animal's stress hormones. That suggests that gaining belly fat may be the body's coping mechanism for turning off the stress response. In addition, the theory is that stress hormones may somehow turn on the brain's reward center, and the result is that during times of stress, certain foods actually taste better, making you eat more of them.

"It's why comfort food may reduce stress," says Mary Dallman, UCSF physiology professor and lead author of the rat studies. "It may be that you feel better if you put on belly fat if you're under conditions of chronic stress."

Similar findings have been shown in monkey studies at Wake Forest University. In male and female monkeys fed foods that mimic the typical North American diet, the animals living in stressful situations were more likely to accumulate visceral fat -- that unhealthy fat that accumulates around organs and in the abdomen. 

The evidence is less clear in human studies but still suggests that stress plays a role in weight gain. Research shows that "night-eating syndrome," a problem that causes sufferers to binge eat, is linked to high stress hormones. People with diseases associated with extreme exposure to cortisol, such as Cushing's disease, also have excessive amounts of visceral fat.

Last fall, a Yale University study reported that otherwise lean women with excess belly fat have an exaggerated response to the stress hormone cortisol. The research, published in Psychosomatic Medicine, looked at lean and overweight women who stored fat at the waist compared with those who stored fat at the hips -- and examined their stress responses over three consecutive days. The study found that the women with abdominal fat consistently secreted more cortisol in response to stressful lab tasks, compared to women with the hip fat.

Supplement makers have tried to cash in on the research by offering herbal remedies they claim will lower cortisol levels and help people lose weight. Researchers and federal regulators say the claims aren't backed by science, and both the Food and Drug Administration and the Federal Trade Commission have taken action against firms selling the remedies.

One product, CortiSlim, marketed by Window Rock Enterprises of Brea, Calif., has touted its product in a much-seen infomercial. After receiving warnings from the FDA and the FTC, the firm has changed its advertising claims, but the case is still pending. In a statement, the firm says the FTC hasn't objected to its current campaign, and its products come with a money-back guarantee.

Another firm, the Carter-Reed Co. of Salt Lake City, maker of Relacore, has sued the FTC in U.S. District Court, contending that it has a right to make its marketing claims, which it says are truthful.

Both the FTC and scientists say there's no evidence the pills actually lower cortisol levels or that lowering cortisol will make a meaningful difference in weight. The mechanism that causes the body to accumulate abdominal fat is likely far more complicated, says Dr. Dallman. However, the stress-fat link does suggest that many of the nation's dieters are missing out on a key component of weight management if they aren't also trying to manage their stress. Exercise is an obvious way to manage stress, but even less strenuous options -- like yoga, meditation or massage may be useful in a weight-loss program.

"One of the things people miss is exercise not only burns calories, but it changes the way you respond to stress, which may be one of the reasons why exercise is important and underappreciated," says Carol Shively, pathology professor at Wake Forest University School of Medicine. Stress management "might be the one weight-loss strategy that society hasn't really addressed." 

By Tara Parker-Pope                                                                                                                    Wall St. Journal via Yahoo! Finance - Fri, Jul 22, 2005                                    

 The Wall Street Journal Online