Not only can stress ruin your outlook—it can make you gain weight. Here's how it's affecting your waistline.

Not only can stress ruin your outlook-it can make you gain weight. Here's how it's affecting your waistline. Watch: 3 Foods to Beat Stress

It turns out that a stressful event can slow down our metabolism-so much so that we could gain an extra 11 pounds over the course of a year, says a new study in Biological Psychiatry.

"We found that women who were stressed burned 104 fewer calories the next day than women who weren't stressed," says study co-author Martha A. Belury, Ph.D., R.D., nutrition professor at Ohio State University.

Belury wasn't even measuring huge life-changing stresses, but just everyday anxieties like caring for aging parents and kids.

"The stressed women had a slower metabolism, higher levels of insulin, which contributes to fat storage, and higher levels of the stress hormone cortisol after a meal," says Belury. (Women with a history of depression had even higher levels of cortisol post-meal than women without a similar history.)

Cortisol increases our chances of gaining fat, in particular visceral fat, the dangerous kind that sits in our midsection and surrounds our organs. Visceral fat has a hand in raising cholesterol and insulin resistance, setting the stage for type 2 diabetes and heart disease.

While all of the women in the study ate the same meals, calorie-for-calorie, real life doesn't work that way. In real life, many of us tend to pick junk food-and too much of it-when we're stressed.

"We turn to high-fat, high-sugar, high-calorie foods in times of stress because they're delicious and they literally give us a temporary high by boosting endorphin and dopamine levels in the brain," says Elizabeth Somer, R.D., author of Eat Your Way to Happiness.

And while we may feel better in the short-term after that hot-fudge brownie sundae, the better stress-busting choices are healthy foods.

"Some of our nutrient needs increase when we're stressed. If we get these nutrients instead of fat and sugar, we can calm the stress response and help stop the damage that stress causes," says Somer.

For instance, stress accelerates cellular aging that's associated with heart disease, cancer and Alzheimer's. However, a healthy diet puts the brakes on this process, according to brand-new research.

November/December 2014