Stressing Out
Stress is the body's physiological response to a threat—real or perceived. The stress response prepares the body to either fight the threat or to flee from it. This response serves us well when the threat comes from a wild animal, or from a would-be human attacker. But what happens when the stresses come from pressing work deadlines, rush-hour traffic, money woes, family obligations, and our own high expectations? Then, the hormones that are released set us up for weight gain.
Stress, Your Appetite, and Your Weight
When you are under stress, your body releases several hormones. Two of these, epinephrine and norepinephrine, trigger the fight-or-flight response. The third, cortisol, provides the energy for this response by stimulating insulin release and rapid fat and carbohydrate metabolism. This increases the appetite for high-starch, high-fat foods. If you are under constant stress, your cortisol levels will remain elevated.
To add insult to injury, research has found that high cortisol levels are linked to a tendency to store excess fat in the abdomen (rather than in the hips, thighs, and buttocks). Abdominal fat is particularly dangerous as it places a greater strain on the heart and is also associated with increased risk of cancer and diabetes. Even healthy-weight individuals who are "high-stress responders" have been found to store extra abdominal fat.
Stress also inhibits the release of serotonin, a neurotransmitter that affects appetite, mood, learning, and memory. Carbohydrates help increase serotonin levels, producing a calming effect. It's little wonder that high-carbohydrate foods like breads, pastas, and sweets are sometimes called "comfort foods."
Sleep: The Importance of Vitamin Z
Stress and a lack of sleep may go hand-in-hand for many of us, but it's worth noting that sleeplessness wreaks its own havoc with the metabolism. Studies have shown that just two sleepless nights can depress the production of leptin (the hormone that indicates fullness) and increases production of ghrelin (a hormone that stimulates the appetite). This tends to trigger a craving for simple carbohydrates (cookies, candy, etc.) to provide quick fuel for the brain, which runs on glucose (a sugar).
Lack of Time?
Of course, there is a simple explanation for why we overeat (and don't exercise) when we're tired and stressed: We don't have the time or energy. It takes more effort to buy fresh vegetables, whole grains, and lean meats, and to cook them from scratch, than it does to make a trip to the drive-thru window. When job, family, friends, and volunteer commitments all compete for our time, it can feel wasteful—even selfish—to call a time-out on everything and hit the gym for an hour. In a study published in November 2005, nearly 60 percent of women interviewed cited family commitments as a barrier to exercise.
More on Emotions and Eating
I've focused on stress here because of the double whammy that stress poses to the waistline. However, stress is not the only emotion that can drive us toward food. Many of us also find ourselves reaching for more snacks or extra helpings when we're depressed, angry, or just bored. Then, of course, there is the inevitable link between food and celebrations—cake for birthdays and weddings, turkey for Thanksgiving, barbecues for Independence Day, alcohol on New Year's Eve, candy for Valentine's Day, Easter, Halloween, and Christmas.