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Gotta Have It -- Why?Virtually all women (97 percent) and most men (68 percent) admit to having food cravings, according to one study. For women, chocolate and other sweets top the list, while men often yearn for entrées such as juicy steaks or cheeseburgers with all the trimmings. After menopause, women's cravings may become more like men's. "It's tempting to say that hormonal changes are to blame. But there also could be a group of older women who grew up during the Depression when more value was placed on meat and protein foods, so who knows?" explains Marcia Pelchat, PhD, a food-cravings researcher at the Monell Chemical Senses Center in Philadelphia.
Hormonal swings seem to be at least partly responsible for women's cravings. Levels of both estrogen and the feel-good brain chemical serotonin drop when women are premenstrual. And there's a possibility that sweets, pasta and other carbohydrate foods can boost serotonin, making you feel better. Hormonal changes may also explain cravings for pickles and ice cream or other pregnancy- related hankerings, but so far, there's no solid proof.
Could what we crave be something our body needs? Experts are pretty certain that missing nutrients are not to blame for the vast majority of cravings. True, chocolate provides the body with magnesium. But sad to say, if our bodies really were crying out for magnesium, we would be longing for big green salads, which provide a lot more than the small amount found in a chocolate bar.
Cravings have very little to do with hunger, either. Who is hungry at the end of Thanksgiving dinner when the pumpkin pie is served? And who turns it down? "If you're hungry, you don't really care what you eat. An unflavored bowl of oatmeal will do," says Allen Levine, PhD, director of the Minnesota Obesity Center.
Instead of satisfying hunger, cravings reward us and give us pleasure. Researchers are just beginning to understand the brain chemistry at work here. They have found that the creamy, rich taste of chocolate can give you a rush that's more subdued but not totally at odds -- biochemically speaking -- from what happens in the brain when drug addicts inject heroin or sniff cocaine.
Are Drugs the Answer?
At the University of Michigan, researchers found that cravings for sweets can be turned off with naloxone, a powerful intravenous drug ordinarily used to counteract heroin and morphine overdoses. They gave naloxone to 14 women who were binge eaters, 8 of whom were obese, and to 12 normal-weight women. While getting the drugs intravenously, the women were told to eat as much as they wanted of a mouth-watering array of cookies and candy bars. Once the drug entered their systems, the binge eaters lost interest in the high-cal smorgasbord. (The normal-weight women didn't eat any more or less.) Another Michigan study showed that naloxone squelched the pleasure binge-eating participants got from consuming chocolate and cookies.
This doesn't mean we need a heavy-duty drug like naloxone to curb our appetites, but it does reveal a biochemical relationship between food cravings and drug addiction. "I don't think we should be too horrified" at the parallels, says Dr. Pelchat. "Drugs are bad because they stimulate reward circuits more strongly and quickly than food, and make us neglect our responsibilities and fail to take care of ourselves."
Naloxone is much too powerful for everyday use, but some see promise in the drug Acomplia, currently awaiting approval by the FDA, which may help people lose weight or stop smoking. Still, it's doubtful that any drug will be able to cure our cravings. After all, they're not rational -- and they're not all governed by a single brain chemical. "We would have to know what other pleasures we would block," says Dr. Levine. Another problem with designing a drug: Cravings affect more than one area of the brain. When Dr. Pelchat and researchers at the University of Pennsylvania used functional MRIs to watch responses to cravings, they saw activity in brain areas related to emotion, memory and reward.
Researchers now want to know whether those reward mechanisms in the brain could be satisfied by alternative turn-ons -- music, perhaps, or video games or shoe shopping. That study is in the works. Shopaholics everywhere, beware!
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