How Stress Makes You Fat
Pressure Adds PoundsPressure Adds Pounds
So how and why would strain and anxiety trigger some of us to pile on extra weight? Stress activates the flight-or-fight response, a physiological reaction designed to get your body moving quickly in a physical emergency. When your brain perceives a threat, it sounds the alarm to your adrenal glands (located on your kidneys) to pump out the stress hormone cortisol. The hormone then signals fat cells to quickly release energy, which your muscles can use for a surge of power to "flee" or "fight." When the danger passes, cortisol briefly stays elevated to encourage your body to replenish its fat stores, then returns to normal.
"The system works beautifully if you're running for the last bus home after work. It gives you a burst of energy, which you recover from quickly once you take your seat," says Pamela Peeke, MD, clinical assistant professor of medicine at the University of Maryland School of Medicine, in Baltimore, and author of Body for Life for Women. But when you turn on the stress response for months on end -- worrying about your marriage or mortgage payments -- you do damage. "Then, cortisol levels remain persistently elevated, persistently signaling your body to store fat," says Dr. Peeke.
This mechanism may also affect where flab builds up on your body. Under stress, women who carry excess weight in their abdominal area secreted significantly more cortisol than women who didn't have extra belly fat, according to a study from the University of California at San Francisco. And since deep abdominal fat tissue has up to four times the number of receptors for cortisol as does superficial fat elsewhere in the body, the cells in this area are the most likely to respond and store fat when exposed to extra stress-induced cortisol. Unfortunately, this extra abdominal flab isn't just a cosmetic concern; it is strongly linked to a greater risk of heart disease and stroke, two top killers of women over 50.
The stress-fat connection plays out in our bodies in three other subtle ways, the cumulative effects of which can be hefty.
Stress stimulates your appetite. A persistently high-level release of cortisol relentlessly sends your body the message that you need to refuel your energy stores and also spurs a spike in insulin, the hormone that controls blood sugar levels. Insulin plays a key role in feelings of hunger and satiety.
It awakens high-calorie cravings. "We all know we don't yearn for celery sticks when under pressure," says Elissa S. Epel, PhD, assistant professor of psychiatry at the University of California at San Francisco. Her research shows that women tend to reach for comfort foods -- high-fat, sweet treats like ice cream, candy, or cake -- when anxious. That's because these rich foods stimulate the release of opioids, brain chemicals that produce pleasurable feelings and help ease anxiety, at least temporarily.
It disrupts your sleep. Stress and the associated worrying that keeps you up at night can trigger hormonal changes that encourage weight gain. When researchers tested 1,024 volunteers involved in the long-term Wisconsin Sleep Cohort Study, they found that compared with men and women who routinely slept eight hours nightly, those who logged only five hours had about a 15 percent higher level of ghrelin, a hormone that stimulates hunger, and a 16 percent lower level of leptin, a hormone that signals fullness.
Another study of 924 adults found that normal-weight individuals slept an average of 16 minutes more per day than those who were heavier. This may surprise women who are mistakenly consoling themselves that at least they are burning up energy tossing and turning. "The full story on how a sleep deficit may be linked to weight gain is far from in," says Robert D. Vorona, MD, assistant professor of internal medicine in the division of sleep medicine at Eastern Virginia Medical School, in Norfolk. "But it's safe to say that if stress is preventing you from getting adequate sleep, it's an area of self-care you should pay attention to."