Food and Your Mood (cont.)

The other draw of the sugary, high-fat snack is the fuel it provides. "When people are experiencing negative moods, and also when they are experiencing stress, they need energy," says Thayer. "And food is a very elemental form of energy."

Of course, most of us don't settle for any old food when we feel run down. We go for the gold: sugary, energy-dense treats such as ice cream, cookies, and chocolate. These foods are crammed with easily digested carbohydrates, which the body converts into glucose -- the simple sugar that circulates in the blood to fuel our cells.

Unfortunately, the quick fix that sweet snacks provide is all too fleeting. People often end up eating still more carbohydrates in an attempt to revive their energy levels after the rush wears off.

Why do it, then? Thayer says it is because people are more or less hardwired to respond to instant gratification.

"You may know that you will be feeling bad in 10 minutes or 15 minutes or an hour, but it is the immediate effect that controls your behavior," he says.

There's still more bad news about sugary foods. Larry Christensen, PhD, chairman of the department of psychology at the University of South Alabama, believes that eating sucrose-containing (sugar-containing) foods may actually cause depression in some people. In his studies, he eliminated sugar from the diets of depressed people and found that about 25% saw a significant improvement in mood.

"Taking sugar out of the diet and adding it back in can turn depression off and on like a faucet."

"For some people, taking sugar out of the diet and adding it back in can turn their depression off and on like a faucet," says Christensen. "It can take a week or two weeks to have an effect, but most people will feel better in a week." It's not clear why sugar has such a profound effect on mood, but it may be linked to exhaustion. "Sugar boosts energy initially, but then it has the paradoxical effect of inducing fatigue," explains Christensen. "And if an individual is constantly fatigued, things are hard to do, and it's easy to become very pessimistic."

A Place for Comfort Foods

But before you throw out that secret stash of extra Halloween candy, remember this: You may not be one of those people who is especially sensitive to sugar, and as long as you partake of sweets in moderation, they probably won't do you any harm.

Also, according to one recent study, there may be a good reason for craving comfort food during tough times. When researchers at the University of California in San Francisco subjected rats to chronic stress over a few days, they found that the rodents preferred to eat sugar and fat.

"Not the ordinary, everyday boring food, not the regular rat chow," says Mary F. Dallman, professor of physiology at the University of California, San Francisco, and the chief investigator on the study. "They went for sucrose and fat."

And when the rats ate these foods, their brains produced less of the stress-related hormones that normally trigger the fight-or-flight response. "To me, this is enormously exciting," says Dallman. "I think this is the first data that show that there might be something good about eating comfort food."