[LindaT]

Is a morning without orange juice or coffee unthinkable? Can you eat just one cookie, or do they keep calling from the cupboard until they're all gone? Do you sometimes feel the overwhelming urge to crunch on something and chips, not apples, are the only thing that will work?
For most of us, forgoing favorite foods at certain times is not only unthinkable, it seems beyond our ability. Many wonder if such intense desires, or cravings, are driven by a physiological need. And some people even call foods they strongly desire "addictive."

Clearly, researchers don't classify them in that way. However, they remain unclear whether a legitimate physiological basis for intense desires for certain foods truly exists, citing difficulty in isolating psychological, social and cultural factors that play a strong role in food choices.

Explaining Food Cravings

Some researchers speculate that cravings arise in an attempt to supply the body with nutrients it lacks.

For example, carbohydrate cravings commonly reported by dieters may be due to a diet too low in calories.

"Carbohydrate cravings can simply be from hunger because your blood sugar levels are too low," says Susan Schiffman, Ph.D., professor of medical psychology at Duke University Medical Center. She also says such cravings can be based on other physiological needs.

When some people count calories, they end up getting most of their calories from fat and then the carbohydrate portion of their diets is too low.

Likewise, carbohydrate cravings experienced by heavy exercisers could result from depletion of glycogen stores, which carbohydrates replenish.

Carbohydrate cravings might be explained by a potential feedback mechanism between carbohydrate and serotonin. Serotonin is a brain neurotransmitter that some researchers hypothesize is involved in the regulation of carbohydrate intake. The theory suggests that too few carbohydrates result in reduced levels of serotonin, which then drives the craving.

Not By Bread Alone
But Adam Drewnowski, Ph.D., director of the Human Nutrition Program at the University of Michigan, doubts the serotonin carbohydrate link. "Most people don't crave just carbohydrates; very few want potatoes, bread or pasta. Most want some sweet, high-fat food," he said.

Instead, Drewnowski believes some of the same physiological mechanisms involved in cravings for opiates may play a role in food cravings. His studies show that with infusions of various opiate-blocking drugs, preferences for foods high in fat and sugar decrease. He speculates that opiate blockers interfere with the ability to experience pleasure, including the pleasure derived from the tastes and textures of foods.

If foods with pleasurable tastes and textures are used as a reward or to provide solace, a practice commonly begun in childhood and continued throughout life, then the psychological component for craving such foods grows even stronger.

For example, while also tasting pleasant, foods such as ice cream and cookies rank high as "comfort foods" - foods eaten in an attempt to soothe away troubles. The desire for such items may reach stronger proportions during stressful times.

Just as people learn to expect pleasure from certain foods, cravings for foods may be influenced by cultural associations. Many people have strong expectations to have certain foods at certain times and places.

Danger of Dieting
The deprivation of dieting also is believed to underlie cravings for certain foods. While following diets that prohibit rich, high-calorie, often-favorite foods, dieters frequently report overwhelming desires for these foods. Unable to resist, they usually give in to their cravings. And once they give in, they frequently overindulge.

"Research shows that people tend to binge if they've been restricted," says Elizabeth Markley, Dr. P.H., R.D., assistant professor at the University of Connecticut.

"We don't know how much of that is purely psychological - simply wanting what you can't have."

Managing Food Cravings
How we make food choices is a complex issue. Beyond the basic issue of satisfying hunger, some of the most important physiological factors may be those of the food itself - taste, texture, color, aroma and temperature.

Whether any innate "wisdom" of the human body plays a major role in determining our food choices is unclear. But our associations with food - what particular foods signify in terms of the emotions they evoke - clearly do have great influence.

"Attempting to ignore these influences, as is often prescribed in these health-conscious days, may set people up for aberrant eating behaviors, such as food cravings that result in bingeing," said Marsh Hudnall, M.S., R.D., nutrition director of Green Mountain at Fox Run, a women's weight management facility.

"By trying to totally avoid certain foods, people instead tend to over consume them in the end," she said.

In fact, Hudnall and other experts predict moderation will prove to be the best strategy for managing food cravings.

"Eating all foods in moderation within the context of a well-balanced diet allows for the many factors that drive our food choices," she said.

In the final analysis, whether future research shows food cravings are physiologically-based or psychologically-based or both, blaming the specific foods for our own choices may be a mistake.

Calling it "no-fault psychology," some scientists fear that people can use such beliefs as an excuse to absolve themselves of personal responsibility for their actions. In the long run, that could undermine a sense of personal control with negative effects on long-term health and well-being.

Will the Real Diet Food Please Stand Up?
Among weight-management experts, it's a familiar story. In an attempt to avoid going off their diets, dieters literally stuff themselves with carrot and celery sticks, all the while craving ice cream, potato chips and candy.

But ice cream and the like eventually win.

Further, such foods win big. Out of guilt, or with the intention that they'll go back on the diet tomorrow and have to forgo "forbidden" foods again, dieters frequently overindulge. When they do return to their diets, the vicious cycle begins again.

How can you break this cycle? Marsh Hudnall, M.S., R.D., program director of nutrition at Green Mountain at Fox Run, says research shows that food cravings are satisfied best by the actual substance that is craved.

"Forget the carrot sticks and have a reasonable portion of ice cream, if it's ice cream that you really want," she says. "In moderation, favorite high-calorie foods can help you stay within a well-balanced diet and achieve a healthy weight."