Food and Your Mood

Why moods can tempt you to indulge -- and what to do about it

By Pamela Donegan
WebMD Weight Loss Clinic - Feature

Reviewed By Kathleen Zelman, MPH, RD/LD

It's one of those days. Deadlines looming. Meetings all morning. The boss on a rampage. Your assistant out sick. Your inbox overflowing. And it's only Monday afternoon!

You're overwhelmed and exhausted, and all you can think about is that candy bar stashed in your desk drawer. You reach for it, your mouth watering in anticipation. You're sure it's just the thing to boost your energy and calm your nerves.

But is it really? Not according to Robert Thayer, PhD, professor of psychology at California State University in Long Beach and author of Calm Energy: How People Regulate Mood with Food and Exercise. Thayer's research has shown that the boost in mood people get from sweet snacks like your candy bar is short lived at best.

"In fact, in one study, we found that people were more tense and tired an hour after they had eaten a candy bar than before it," says Thayer.

So why do we crave sweet snacks at times of stress? For one, they taste great. OK, that's a no-brainer, but a megadose of sugar does more than tickle your taste buds. It actually stimulates your brain's pleasure center while temporarily lowering your body's sensitivity to pain. Healthcare professionals who work with newborns often take advantage of this by putting sugar drops on an infant's tongue to ease the distress caused by medical procedures.

It isn't just the sugar, though. High-fat content in food also creates pleasurable sensations and lessens pain. In a 1997 study in Britain, volunteers who ate high-fat pancakes an hour and a half before dunking their hands into ice-cold water reported less discomfort than others who had eaten equally caloric, but low-fat, pancakes.

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."