We crunch. We Ab Blast. We eschew carbs. Heck, we'll even go under the knife to get rid of ab flab.

Unfortunately, recent research shows that you can crunch until you crumble and diet till you're drained of energy, but if your days are full of stress, the perfect six-pack -- or even a flatter midsection -- will continue to elude you.

That's because fat in the abdominal area functions differently than fat elsewhere in the body. It has a greater blood supply as well as more receptors for cortisol, a stress hormone. Cortisol levels rise and fall throughout the day, but when you're under constant stress, the amount of the hormone you produce remains elevated. With high stress and, consequently, high cortisol levels, more fat is deposited in the abdominal area since there are more cortisol receptors there.

But ab flab is not the only price you'll pay for chronic stress (the kind created by a marriage that's unraveling, a job you hate, problems with your health -- rather than, say, tension caused by a traffic snarl). Chronically high cortisol levels also kill neurons in the brain and interfere with feel-good neuro-transmitters -- such as dopamine and serotonin -- which can lead to depression and feeling more stressed.

More stress = more fat

In short, the whole issue of abdominal fat goes far beyond how you look in a bikini: The fat at your waist -- what researchers call central obesity -- is associated with higher rates of cardiovascular disease, type 2 diabetes and several types of cancer. And while it's true that heredity plays a role in overall body type (that is, whether you are more of an "apple" than a "pear"), says Brenda Davy, Ph.D., R.D., an assistant professor at Virginia Tech in Blacksburg, "genetics accounts for only 25-55 percent of the tendency to develop the most serious diseases associated with abdominal fat -- the remainder is lifestyle."

Ongoing research at the University of California, San Francisco (UCSF), is showing that it doesn't even matter if a body is otherwise thin; if stress levels are high, ab fat will increase. "People called 'high-stress responders' [those who secrete more cortisol in response to stress than others] have more central fat, regardless of body weight," says Elissa Epel, Ph.D., an assistant professor in the psychiatry department at UCSF and the author of several studies on stress and eating behavior in premenopausal women.

The best diet to lose ab flab

All of this means there's one simple place to start: If you want to get rid of the fat at your midsection, begin by introducing stress-reduction techniques such as meditation, exercise and deep breathing. The Mind/Body Medical Institute in Chestnut Hill, Mass. -- founded by Herbert Benson, M.D., author of The Relaxation Response (Quill, 2000) and an expert on the harmful effects of stress -- utilizes all of these techniques in its Lighten Up program, in which participants learn to manage the stressors that trigger the hormone changes that play a role in weight gain.

The Lighten Up program has one other component that's essential to successful weight loss: Participants follow the Mediterranean Diet, which emphasizes nutritious foods such as fish, nuts and seeds, whole grains, beans, fruits and vegetables. Unlike the typical American diet, the Mediterranean eating plan eliminates or limits saturated fats and processed foods and includes a moderate amount of healthy fats, especially omega-3 essential fatty acids. (The best sources of omega-3s are fatty fish such as salmon, herring, sardines and mackerel; if you don't like fish, try flaxseed or walnuts.)

The Mediterranean Diet appears to have what researchers call an anti-inflammatory effect on our bodies' many systems and organs, meaning that it fights the destructive effects of chronic stress.

True anti-stress foods

Eating so-called "comfort foods" (carbohydrate-rich fare such as cookies, bread and pasta) may help you feel calmer in the short term, but proceed with caution "Beware of 'Comfort Carbs'"). Over time, the price you'll pay for trying to reduce your stress with low-fiber, high-carb (and high-calorie!) foods is more abdominal fat.

In her most recent study, Epel found that men and women who overate in response to stress had higher levels of both insulin and cortisol, elevating their risk for more-serious diseases, including diabetes.

The nutrients that show the most promise for long-term stress relief are the Mediterranean Diet's keystone: the omega-3 fatty acids. As odd as it may sound, getting more of these "good" fats has been associated with a reduction in body fat, including abdominal fat. Several recent studies show that eating omega-3 fats can reduce output of another stress hormone, epinephrine (aka adrenaline).

While experts do know that high cortisol levels contribute to abnormal accumulation of abdominal fat and the subsequent development of life-threatening diseases, they haven't yet come up with a magic nail to permanently deflate your spare tire. In the long term, adopting habits such as regular exercise, relaxation techniques and a Mediterranean-style diet are the keys to creating a healthy, happy life -- and not just the antidote to ab flab!