Hitting the drive-through after a rip-your-hair-out day isn't something we're proud of, but hey, it happens. And if your pants feel a little tighter the next day, it may not just be salt-bloat from those (delicious) cheese fries: Being stressed out actually changes the way food is metabolized, making so that calories are stored as fat, according to a new Ohio State University Wexner Medical Center study—but you most likely won't gain the 11 pounds you may have read in other stories.
While the link between chronic stress and weight gain isn't new, this is the first research to look at exactly how this happens and, even scarier, how quickly this happens. After establishing the baseline metabolisms for 58 women, researchers asked them to back to the lab the next day to fill out a questionnaire about their activity levels, sleep, mood, and stress levels. The group then ate a meal containing 930 calories and 60 grams of fat, about the same as a typical fast food meal, and researchers monitored their metabolisms for any changes.
Women who reported having a stressful event the day before burned 104 fewer calories than their less-stressed counterparts. These results were particularly fascinating because it was all due to internal adjustments in the body. The stress didn't cause the women to eat more food, sleep less, or even move around less; rather the stressful event triggered some change in the body that told it to slow down metabolism.
Anxious subjects' blood work and metabolic output showed higher levels of insulin and decreased fat oxidation. Janice Kiecolt-Glaser, Ph.D., lead author of the study, believes the primary culprit is the "stress hormone" cortisol. The more stressed you are, the more cortisol is released into your blood stream. This causes insulin to spike, and increased insulin decreases fat oxidation, which leads to more pounds around your belly. Stressed women with a history of depression fared even worse and also had higher levels of triglycerides, a known risk for heart disease.
And the stress didn't have to be much. The study described stress as arguments with co-workers or spouses, disagreements with friends, trouble with children, or work-related pressures—all everyday things we all deal with at times. But those little things add up, possibly to the tune of about 11 pounds of weight per year—assuming you're eating this way every day. A more realistic single "comfort food" meal a week would only pack on about 1 1/2 pounds.
Kiecolt-Glaser adds that another well-known side effect of both depression and stress is that they make you crave fatty, sugary foods, thereby creating a vicious cycle where you crave the very things that will have the most detrimental effect on your health.
But there are things you can do to mitigate the effects. "When you're stressed, you reach for what is easiest. This is why it's important to have alternate foods easily available," says Martha Belury, Ph.D., the nutritionist for and co-author of the study. She recommends having foods typical to the Mediterranean diet, such as whole grains, legumes, proteins, and lots of fruits and vegetables, handy in your pantry and fridge. The researchers add that exercise is key too, as it both reduces stress and increases metabolism. It's also been found to help mild-to-moderate depression.
At the end of the (terrible, horrible, no-good, very-bad) day, Kiecolt Glaser says that while we can't always control the amount of stress in our lives, knowing about the effects of comfort foods on our metabolism might help us to make better choices. Something to ponder the next time those take-out menus start calling your name.