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Few foods are more alluring than chocolate. "Chocolate is a drug of abuse in its own category," jokes Dr. Louis Aronne. "It’s ahnost as if people have chocolate receptors in their brains. " That may not be too far off the mark. In a recent book called "Breaking the Food Seduction," Dr. Neal Barnard contends that certain foods—including chocolate, cheese, red meat and practically anything combining sugar and fat—are just plain addictive. " It’s not that you lack willpower. These foods stimulate the release of chemicals in the brain’s pleasure center that keep you hooked. " Besides tapping the brain’s own "feel good" chemicals, Barnard says, some of these foods contain drug-like molecules (分子) of of their own. Cheese delivers casomorphins, the same compounds in a mother’s milk that help an infant bond during nursing, he says, but cheese is even more powerful, because it delivers casomorphins in an undiluted form. The result: "We’re bonding to our refrigerators. " Other scientists doubt these drug-like compounds have enough force to make the foods addictive. But no one denies that fat and sugar exert a strong appeal. The brain is designed to reward eating and other behaviors that promote survival. And throughout history, with food relatively hard to come by, what prmnoted survival better than calorie-dense foods packed with fat and sugar Besides, fat and sugar also calm the brain, lowering levels of stress hormones. "That’s why we call them comfort foods," says physiologist Mary Dallman. But comfort is different from addiction. In classic addiction, the brain grows less sensitive to a pleasurable substance, and the addict requires higher and higher doses to derive the same rewards. Can food cause that kind of change Perhaps. In a new study, Ann Kelley offered rats either plain water or a high-calorie chocolate drink. Over a two-week period, the animals drank more and more chocolate, but produced fewer brain opiates(镇静剂) in response. "You see the same thing in rats on morphine or heroin," she says. Admittedly, some foods can be hard to stop eating. But these foods are less habit-forming than alcohol—and most people can enjoy a drink without becoming alcoholic. The real problem today may be that we’re constantly surrounded with food—and can’t undo millions of years of evolution. Which of the following CANNOT explain our addiction to sugar and fat
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This summer, for the first time, Emory College let freshmen pick their own roommates in an online roommate-selection system that works on the same principles as computer dating. Students, using screen names to hide their identities, posted profiles of themselves detailing personality attributes, work habits, music and food preferences, and answers to questions like whether they hoped to "do almost everything" with their roommate or "lead separate but compatible lives. " Roommate-matching is a summer ritual that plunges college housing offices into the most intimate realm of sleep patterns, cleaning habits, and noise tolerance. Online matching is on the cutting edge. Housing officials at Emory, in Atlanta, say they expect that letting students pick their own roommates will increase the likelihood of compatibility. And there’s little risk of hurt feelings if the e-mail exchanges do not lead to a match, since the initial round of contacts is done under screen names. Several studies have shown that roommates have an impact on the attitudes and social behavior of those they live with. And one recent study found that a roommate’s academic performance has a small, but statistically significant, effect on the other roommate’s grade-point average. Other studies, however, did not find that effect. The business of assigning roommates varies widely across the country. At Davidson College, the housing staff sort every freshman with careful hand-selection. The Davidson philosophy is that roommates should be as similar as possible, while halls should be as diverse as possible. "We had a match that seemed perfect, until we discovered that one was a cattle rancher’s son and the other was a vegan (绝对素食者) ," said Ms. Kromm. "They should definitely meet, on the same hall. But we didn’t want to put them in the same room. " Occasionally, an incoming student asks to be paired with an Asian, or says she might not be able to get along with a Republican. In such cases, Ms. Kromm will remind them that Davidson does not accept roommate preferences based on race, ethnicity, and religion. Davidson’s care in matching pays off. " By Christmas last year, we had only four requests for roommate changes out of 480 students. " No one knows whether computer-matching works as well. But at Emory, so far, student reaction seems to be telling something: the online system is overwhelmed with clicks. In computer matchmaking, initially students do not reveal their ______.
A complex operation called spinal fusion has emerged as the treatment of choice for many kinds of back pain. But a number of researchers say there is little scientific evidence to show that for most patients, spinal fusion works any better than a simpler operation, the lamineetomy (椎板切除术). Some people would be better off with no surgery at all. Even doctors who favor fusions say that more research is needed on their benefits. In the absence of better data, critics point to a different reason for the fusion operation’s fast rise: money. Medicare can pay a surgeon as much as four times more for a spinal fusion as for a laminectomy. Hospitals also collect two to four times as much. "We all cave in to market and economic forces," said Dr. Edward C. Benzel. Though doctors, as a rule, should favor the least complicated treatment—with surgery being the last resort — Dr. Benzel estimated that fewer than half of the spinal fusions done today were probably appropriate. Doctors and hospitals are not the only players with a financial stake in fusion operations. Critics blame the companies that make the hardware for promoting more complex fusions without evidence that they are significantly more effective. Some sort of hardware is used in almost 90 percent of lower-back fusions and the national bill for the hardware alone has soared to $ 2.5 billion a year. The hardware makers acknowledge giving surgeons millions of dollars for consulting and researches, but say the money promotes technical and medical advances that improve back care. But a lawsuit brought by Scott A. Wiese, a former sales representative of Medtronic-the biggest maker of spinal hardware, accused the company of trying to persuade surgeons to use its products with offers of first-class plane tickets to Hawaii and nights at the finest hotels. Medtronic said it did nothing wrong, and it denied the accusations in the lawsuit. But the company disclosed earlier this year that the federal government was investigating charges that it paid illegal kickbacks to surgeons. Federal officials declined to comment on the investigation, and Medtronic said it would vigorously defend itself. Still, between the allure of money and the quest for breakthroughs in treatment, some prominent spinal surgeons say that back care has gone astray. The author’s attitude towards spinal fusion is probably ______.
Questions 11 to 18 are based on the conversation you have just heard.
Children are getting so fat that they may be the first (36) to die before their parents, an expert claimed yesterday. Today’s youngsters are already falling (37) to potential killers such as diabetes because of their weight. Fatty fast-food diets combined with sedentary lifestyles (38) by televisions and computers could mean kids will die (39) young, says Professor Andrew Prentice, from the London School of Hygiene and Tropical Medicine. One of the major reasons why children now are at greater risk is that we are getting fatter younger. Many nations now (40) more than 20 per cent of their population as (41) obese and well over half the populations overweight. At the same time, the shape of the human body is going through a huge (42) shift because adults are getting so fat. Professor Prentice said the change in our shape has been caused by easily available high-energy foods combined with a (43) drop in the energy we use as a result of technology developments. He is not alone in his concern. (44) . Obesity also increases the risk factor for strokes and heart disease as well as a diabetes . (45) . So will parents outlive their children Yes, when the offspring become grossly obese. (46) .
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