2. 外语
  3. For most people, fat is a burden. It doesn’t really matter where it appears, we just don’t want it. But it turns out that our bo

For most people, fat is a burden. It doesn’t really matter where it appears, we just don’t want it. But it turns out that our bo

admin2010-12-04  74
问题       For most people, fat is a burden. It doesn’t really matter where it appears, we just don’t want it. But it turns out that our bodies also make a unique form of fat tissue that behaves remarkably unlike any other: rather than storing excess energy, this fat actually burns through it. It’s called brown fat and health experts confirm for the first time that healthy adults have stores of this tissue, which researchers hope to study further as a potential new weight-loss treatment.
      Human newborns have been known to have any significant deposits of brown fat, so called because of its abnormally high concentration of dark---colored mitochondria (线粒体), the engines that sustain cell activity. The primary purpose of brown fat is to regulate body temperature: the mitochondria-packed cells are designed to burn high quantities of sugar, and release that energy as heat a mechanism that newborns rely on to keep themselves toasty.
      As people age, however, the body becomes better at regulating temperature, so brown-fat stores shrink and white fat starts to emerge. A research team in Sweden has found that healthy adults retain a sizable amount of fat in the front and back of the neck expressing the same proteins as brown fat.
Identifying the presence of brown fat is one thing, but activating it to burn more sugar is another. Two studies confirmed that brown-fat cells become more active in the cold. But before we consider joining the Polar Bear Club, can brown fat actually cause weight loss? Brown fat may indeed allow a person to burn more calories (卡路里) with the same amount of consumption. On the basis of animal models, researchers calculate that 50g of brown fat could burn about 20% daily calorie an average person takes in. Leaner people tended to have more brown-fat deposits than overweight individuals. Interestingly, women were ’twice as likely as men to have active brown fat.
      Still, the findings don’t necessarily mean that activating brown fat leads to a slimmer waist. For one thing, the body is especially good at maintaining balance, which is why a boost in calorie-burning can often make it hunger signal and prompt people to eat more to make up for the loss. And even if drug companies could find a way to activate (刺激) brown fat safely, that excess activity could throw off other metabolic (新陈代谢的) systems and damage your health.  
According to Para. 4, we can safely draw the conclusion that ______.
选项 A、it is totally impossible to lose weight by activating brown fat
B、our brown fat will be more active if we go to the North Pole
C、brown fat can surely make you thinner than before
D、to keep fit, an average person should eat 50g brown fat
答案B
解析 推理判断题。第四段主要说明促进棕色脂肪活性的方法以及其他一些研究结果。根据第二句，研究证实在寒冷的环境里，棕色脂肪细胞会变得更活跃，而北极非常寒冷，因此人们理所当然也认为如果去北极的话，体内的棕色脂肪会变得很活跃，可能更有助于减肥，故B)为正确答案。
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