Tough day at work? That might be one more reason to watch what you eat when you get home.

It is well-established that people often eat to relieve stress. But a study published in the monthly Journal of Applied Social Psychology (search) found that even after the stress was over, women who were more frustrated by it ate more fatty foods than those who were not as frustrated.

One surprising finding: Men's snack preferences stayed the same, regardless of their stress levels.

"A lot of studies have looked at what happens during stress," said lead researcher Laura Cousino Klein, assistant professor of biobehavioral health at Penn State University (search). "What we wanted to know is what happens after the stress is over."

Klein and her colleagues presented the participants with a variety of tasks over 25 minutes while randomly blasting them with office sounds — a phone ringing, a typewriter clacking — at 108 decibels, the same noise level you would get standing next to a jackhammer.

After that time was up, the participants were left alone for 12 minutes and offered a magazine, water and a tray of snacks — fatty cheese, potato chips and white chocolate, and lowfat popcorn, pretzels and jelly beans.

After they had snacked, they were asked to trace their way through an unsolvable maze.

Those women whose stress level was the highest during the maze exercise — their blood pressure and heart rate remained high, and they quickly showed frustration with the maze — tended to eschew the lowfat snacks in favor of fattier treats.

Women who were highly frustrated by the noise stress ate 65 to 70 grams of the fatty snacks during the break, twice as much as the women who were not as frustrated.

"What's interesting is that during the noise, during the work time, people rise to the occasion," Klein said. "They accomplish the job they have to get done, and they do quite well at it. They block all the other things that are going on in their environment.

"But there's a psychological and mental cost to that, and what that is is that after that's over, once the stressor is done, then we see this behavioral element."

Klein said a corollary can be seen most weekends, when people are most likely to binge drink or stray from their diets.

The results of the study, completed in 1996 and published in the journal's March issue, did not surprise William Kelley Jr., director of the Wellness Center at Green Mountain College (search) in Poultney, Vt.

"Your body doesn't stop dealing with a stressor just because the stressor is no longer in place," Kelley said. "You're still processing an event long after it happens."

Dr. Christopher Still, director of the Center for Nutrition and Weight Management at Geisinger Medical Center (search) in Danville, Pa., said knowing that stress effects can be long-lasting can help people anticipate that reaction and find other ways to deal with stress, such as exercise.

In the study, men ate about 40 grams of fatty snacks, regardless of their stress levels.

Klein said the explanation might have to do with the way men and women handle stress, an idea Kelley agreed with.

"I definitely have seen the same thing, and I want to be careful how I word that because I don't want to start a gender debate," Kelley said. "But the men that I usually see are sort of, `It happened, it's over, let's deal with it and move on,' whereas the women tend to struggle more with the processing time of an event afterward. I'm not sure if that's genetic programming or society."