THE NEED TO FEED SCIENTISTS BELIEVE THAT FOOD CRAVINGS ARE LINKED TO THE BRAIN, AND ARE GENERALLY HARMLESS - SO GO AHEAD AND INDULGE YOURSELF.

Byline: Evan Henerson Staff Writer

It creeps up on you, ringing the tiniest of bells in your ear. A suggestion becomes an itch, then a full-fledged give-it-to-me-or-else demand: ``I really must have a Milky Way bar.''

The majority of us - or at least, those of us without the will power to resist - will go directly to the nearest vending machine, buy the Milky Way bar and satisfy the urge commonly known as a food craving. Others have been conditioned to figure out a way to satisfy the craving with a less-caloric substitute, such as a piece of fruit. Still others can simply ignore the ``must have chocolate'' feeling and not eat anything.

Few of us have stopped to ponder from whence that food craving originates. And scientists aren't sure, but many suspect the impulse for a specific food (or type of food) is spurred by the brain. Unfortunately for research purposes, cravings are common yet unpredictable and fleeting enough that scientists can't easily study them.

The people who seem to have cravings most frequently - pregnant women or women during a certain point of their menstrual cycle - don't make ideal test subjects. Their cravings - pickles and ice cream, anyone? - are linked to hormonal fluctuations.

It's even difficult to come up with a definition since there's a fine line between a strong preference and an actual craving, says Dr. Paul Rozin, professor of Psychology at the University of Pennsylvania. If you feel like eating an egg salad sandwich for lunch this afternoon, you may simply be experiencing a preference. Very common. If nothing but an egg salad sandwich will do day after day, lunch after lunch, that's a craving.

``Most wouldn't consider it a craving if it isn't cyclical, recurrent and pressing,'' says Rozin, ``like if you're willing to go out in the rain for something.''

Chocolate is the most commonly craved food, followed not so closely by pizza, salty foods (like potato chips and french fries), sweets, bread, protein and fatty foods. Caffeine, grouped as a beverage, not a drug, is a heavily craved item that - unlike foods - can produce withdrawal symptoms. While you might add ``-oholic'' to your favorite food in conversation, nutritionists say you cannot be addicted to food the way you may be nicotine and alcohol. However, some believe craving feelings are part of the addiction complex that includes tolerance, withdrawal symptoms and loss of control.

``Nobody gets withdrawal from not eating pizza,'' says Dr. David Heber, director of the UCLA Center for Human Nutrition and author of ``The Resolution Diet.''

Heber and UCLA researchers are about to begin a nationwide study to determine whether an experimental drug called Ecopipan can help individuals curb food cravings and thereby lose weight. The theory behind the study is that certain foods stimulate a transmitter in the brain called the dopamine receptor, which produces feelings of pleasure.

Pleasure-stimulating foods - often referred to as red light or trigger foods - are often unhealthy. But we want them anyway, sometimes because we associate them with fond memories or because we use them as a way to reward ourselves. Had a bad day? Hey, you got through it. Reward yourself with a piece of pie.

``I think a lot of cravings have some emotional origin,'' says Dr. Barbara Rolls, professor of nutrition at Pennsylvania State University. ``It's a comfort food kind of thing. You're eating just because you want to treat yourself, and you don't need science to tell you what's happening.''

When we eliminate foods we enjoy from our diet, some scientists say the craving is the body's way of protesting that food's absence. Most successful weight-loss plans will have dieters cut back on unhealthy foods rather than cut them out completely.

``I taught a class in gestational diabetes where, before the class, one of the women went out and ate half a watermelon because she knew in the class we would tell her she couldn't have it,'' said Patty Carbone, a registered dietitian in the health education division of Kaiser Permanente in Woodland Hills. ``Patients will go and have half a gallon of ice cream. It's like one last fling.''

But will a pre-diet binge eliminate the craving? Unlikely, says Karen Miller-Kovach, chief scientist for Weight Watchers International.

``If you set yourself up in terms of creating an environment of deprivation, then you'll have feelings of deprivation and you'll want what you're being deprived of,'' says Miller-Kovach. ``If you're trying to lose weight and you tell yourself you can't eat pizza, you're setting yourself up for failure.''

But even those who believe a food craving is a chemical rather than a psychological urge say discipline and behavior modification can be just as effective as medication. Bottom line: While everybody should be careful about their diet, food cravings haven't proved dangerous. (Unless, say, you find yourself obliging a doughnut craving five times a day.)

The exception is a peculiar condition called pica, which can also be associated with pregnant women. People with this condition crave non-food items like clay, dirt or ice. Some scientists believe this is the body's way of signaling an iron deficiency.

Addictions are very much the subject of ongoing research and grant funding. Even pica gets its own research niche within university medical schools. But nutritionists say hard data on the simple food craving will probably remain elusive until a link between cravings and weight loss can be more firmly established.

``The body is so complex, it's like looking for a needle in a haystack,'' says Dr. Jeffrey Hampl, a dietitian and spokesman for the American Dietetic Association. ``From a research point of view, it's difficult to obtain subjects (to study cravings). Medical research has bigger eggs to fry.''

Bigger eggs. Gosh, a Spanish omelet would sure hit the spot right now. Wonder if that diner down the street is still serving breakfast ...

CAPTION(S):

drawing, photo

Drawing:

(cover -- color) CRAVINGS

Why do we have them?

Jorge Irribarren/Staff Artist

Photo:

Chocolate is the most desired item, with salty foods, sweets, protein - even caffeine - following far behind. The pickle-and-ice-cream cravings of pregnancy are due to hormonal fluctuations.

Michael Owen Baker/Staff Photographer