Dr. Laura C. Klein, assistant professor of biobehavioral health who led the study, says, "Although other researchers have shown that both men and women eat more during stressful periods, this is the first study to show that eating is affected in some individuals after a stress is stopped.
"In daily life, people often rise to the occasion to deal with stress," she adds. "The real window of vulnerability may be after the stress is over. For example, women exposed to a week of frustrating job stress could be especially vulnerable to overeating on the weekends."
The researchers' results are in the current issue of the Journal of Applied Social Psychology in a paper, "Gender Differences in Biobehavioral Aftereffects of Stress on Eating, Frustration, and Cardiovascular Responses." The authors are Klein, Dr. Karen S. Quigley, University of Medicine and Dentistry of New Jersey and Department of Veteran's Affairs, Dr. Martha M. Faraday, Uniformed Services University of the Health Sciences and Dr. Neil E. Grunberg, Uniformed Services University of the Health Sciences.
In the experiments, 29 men and 34 women, ages 18 to 45, who thought they were in a study of the effects of noise on performance, were divided into three groups and asked to solve math and geometry problems shown to them on slides. They were only allowed to view each slide for ten seconds before the next slide appeared.
In the first group, while the participant was trying to solve the problems, a loudspeaker placed near his or her chair emitted a noise about as loud as a jackhammer at unpredictable intervals. The participants were shown a button on the side of the chair to turn the noise off but none did.
In the second group, everything was the same as the first group, except that the participants were not told they could turn the noise off. In the third group, the control group, everything was the same, except that participants were not exposed to noise stress. Following the problem-solving session, the participant was asked to sit alone in room for 12 minutes while the next phase of testing was prepared. An assistant brought the participant a snack tray and a pitcher of water. The snacks included pretzels, potato chips, sonoma Jack cheese, white chocolate, jelly beans, and unsalted air-popped popcorn.
After 12 minutes, the participant was asked to solve puzzles by tracing a path through a maze without crossing any lines. Unknown to the participant, one puzzle was solvable but the other one wasn't. The number of times the participant attempted to solve the unsolvable puzzle was used as a measure of the person's persistence or residual frustration level after the earlier math problem-solving session.
The researchers found that women who demonstrated low persistence on the unsolvable puzzle and were, therefore, highly frustrated by the earlier math problem-solving session, ate more of the snacks overall, especially the high-fat potato chips, cheese and chocolate as well as the bland popcorn when compared with the women who were less frustrated.
Men, on the other hand, ate the same amount of snacks regardless of the study group they were in. Exposure to the noise stress, regardless of whether they thought they could turn it off or not, also increased their persistence on the puzzle.
The researchers write, "There are some possible explanations for why exposure to the noise, regardless of perceived control might have increased persistence in men. One possibility is that, for men, noise exposure may have engendered feelings of competition and a desire to assert control or to win (i.e. to successfully complete the tracing task). It also is possible that stressor exposure produced a need for distraction in men, that the tracing task provided an outlet for that need, or that men found the tracing task to be a coping strategy whereas women did not."
The study was supported by the Uniformed Services University of the Health Sciences and grants from the National Institute on Drug Abuse and the Office of Naval Research.