Nov. 17, 2010 -- Feeling stressed out? Gorging on comfort food may help, but it may also hurt.
Scientists have known for some time now that eating calorie-rich foods, commonly known as comfort foods, can help ease stress, even though it can also add flab to the abdomen. But now researchers have come up with a new wrinkle in this ongoing saga.
It isn't the calories that are doing the work. It's the taste buds.
Researchers at the University of Cincinnati set out to see if "pleasurable behavior" causes the neural activity associated with easing stress, and they found that comfort food does the trick. So does sex.
At least among rats, and almost surely people. Over a two-week period, rats that were confined in narrow tubes -- a stressful situation, even for a rat -- were fed a sugar solution (the rat version of comfort food) twice each day.
Their heart rate and stress hormone levels dropped significantly, as expected. They were also more sociable with other rats.
Then they conducted the same experiment using a sugar substitute, so the sweet-tasting drink had fewer calories. Same result, and rats that were introduced to a willing sex partner also saw their stress indicators drop.
Pleasure Properties in Tasty Foods Are Sufficient for Stress Reduction
Finally, they introduced a sugar-rich drink directly into the rats' stomachs, thus bypassing the taste buds. It had no significant effect on the rats' stress levels.
"This indicates that the pleasurable properties of tasty foods, not the caloric properties, were sufficient for stress reduction," said post-doctoral researcher Yvonne Ulrich-Lai, lead author of a study in Proceedings of the National Academy of Sciences.
Ulrich-Lai and James Herman, director of the university's Laboratory of Stress Neurobiology, conducted the experiments with several colleagues.
Their study reached this conclusion: "We now demonstrate that rewarding properties of palatable foods can effectively buffer all major physiological and behavioral responses to stress, and we identify key neural circuits underlying the comfort food effect."
Comfort Foods May Relieve Stress but Contribute to Obesity
The effect, they added, is clearly "hedonic, rather than caloric." If it feels good, it will work, but there's a catch. It's going to show up in your gut. Many research projects have linked stress, and the use of comfort food to relieve it, to the obesity crisis that threatens public health on an astronomical level.
Earlier this year the University of Rochester Medical Center released a study of 2,782 employees of a large manufacturing plant and it showed that the combination of stress on the job, physical inactivity, and collapsing in front of the TV at the end of a long day can be deadly.
Many of the participants in that study had cardiovascular disease, depression, exhaustion, anxiety and excess weight.
Stressed Mice Gained More Weight Than Unstressed Mice
But stress is common in any job that's worth having. No stress means no challenge. Humans have always had to deal with stress, and it was a useful evolutionary strategy. It enabled the body to deal with a wide range of threats, like the "adrenalin rush" when a cave man saw a lion ready to pounce. But chronic stress, like that faced by many factory workers in the Rochester study, doesn't turn off because the "lion" never leaves.
In many ways the workplace these days is more stressful than ever, so more and more people are turning to comfort food as a cure. And according to research from Georgetown University, calories are especially damaging to a stressed animal.
The Georgetown researchers found that stressed mice fed a high-calorie diet (read: comfort food) gained twice as much fat as unstressed mice fed the same diet. They concluded that the stressed animals stored fat differently, and thus were much more likely to become obese.
Sad Person More Likely to Turn to Food Than Happy Person
There is also evidence that stress is not the only culprit. Brian Wansink of Cornell University has long been obsessed with why people eat the way we do, and a couple of years ago he took a look at what he calls the "food-mood" connection. His research shows that a sad person is much more likely to turn to comfort food than a happy person.
Wansink recruited 36 persons to watch a couple of movies, one sad, the other happy. Half watched the upbeat "Sweet Home Alabama," and the other watched the "sad, depressing 'Love Story,'" Wansink said.
"After the movies were over and the tears were wiped away, those who had watched 'Love Story' had eaten 36 percent more popcorn than those who had watched the upbeat 'Sweet Home Alabama,'" he said in releasing that study. Sadness, of course, is no stranger to stress. That which makes us sad may also make us stressed.
But beware of comfort food. The lion may still be nearby.