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Is a morning without orange juice and 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
an overwhelming urge to crunch that only chips, not apples,
will satisfy?
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,
PhD, 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 a depletion of glycogen stores, which carbohydrates
replenish.
Carbohydrate cravings might be explained by a potential feedback
mechanism between carbohydrate and serotonin. Serotinin 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, PhD, 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 says.
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
optiate-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, 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 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 PH, RD,
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 often is
done by prescribed diets in these health-conscious days, may
result in bingeing," says Marsha Hudnall, MS, RD, nutrition
director at Green Mountain at Fox Run. "By trying to
totally avoid certain foods, people instead tend to overconsume
them in the end." In fact, Hudnall and other experts
predict moderation will prove 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 foods choices," she says.
In the final analysis, whether future research shows food
cravings are physiologically-based or psychologically-based
or both, blaming 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.
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