共用题干 第三篇Americans still have been gaining weight,although they have cut thei...

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问题 共用题干
第三篇

Americans still have been gaining weight,although they have cut their average fat intake from 36 to 34 percent of their total diets in the past 15 years.Indeed,cutting fat to control or lose weight makes sense. Fat has nine calories per gram. Protein and carbohydrates(碳水化合物)which break down into amino acids and simple sugars respectively,have just four. Moreover,the body uses fewer calories to metabolize(新陈代谢)fat than it does to metabolize other foods.
But cutting fat from your diet doesn't necessarily mean your body won't store fat. For example, between nonfat and regular cookies,there's trivial difference in calories because manufacturers make up for the loss of fat by adding sugar. Low-fat crackers,soups and dressings can also be just as high in calories as richer versions.No matter where the calories come from,overeating will still cause weight gain.The calories from fat just do it a little quicker. A Wisconsin computer programmer who decided with a diet coach to eat only 40 grams of fat a day learned the lesson firsthand.He wasn't losing weight.Then he showed his food diary to his coach and revealed he'd been eating half a pound of jelly beans a day."They don't have any fat,"he explains.But they had enough sugar to keep him from losing an ounce.
Nonfat foods become add-on foods.When we add them to our diet,we actually increase the number of calories we eat per day and gain weight. That was born out in a Pennsylvania State University study.For breakfast,Prof. Barbara Rolls gave two groups of women yogurt that contained exactly the same amount of calories.One group's yogurt label said"high fat”一the other,"low fat". The"low fat"yogurt group ate significantly more calories later in the day than the other group. "People think they've saved fat and can indulge themselves later in the day with no adverse consequences,"says Richard Mattes,a nutrition researcher at Purdue University."But when they do that,they don't compensate very precisely,and they often end up overdoing it."

选项 What can be inferred from the passage?
A:To avoid being overweight,people should eat nonfat food.
B:Nonfat and regular food have no difference in calories.
C:Americans think it necessary to count calories of food.
D:We can eat nonfat food as much as we like.

答案C

解析主旨推断题。本文第一句就说:虽然美国人减少了脂肪摄入量,但是体重却没有停止增加。接下来就详细分析了为何如此:很多人认为自己选择了低脂或无脂肪食物就会放松警惕,放纵自己吃很多,而这些无脂肪食物中往往添加了很多东西来弥补脂肪的缺失,这样一来导致肥胖问题并没有减轻。因此本题选B。
本题是细节考查题。根据第一段第三句和第四句可知:每克脂肪含9卡路里热量,而protein and carbohydrates则含4卡路里热量,因此本题选C。 B选项“sugar”和D 选项“amino acids”为protein and carbohydrates分解后的产物。
本题是推断题。第二段倒数第二句中强调这个电脑程序员每天吃half a pound of jelly beans,这里从这一非常具体的数据half a pound中可以推断出他吃得太多了。因此选D。
本题是推断题。根据第三段中芭芭拉教授的实验,我们得知食用低脂酸奶的那一组体重增加反而高于食用高脂酸奶的那组,因为食用低脂酸奶的人认为自己摄入了较少的脂肪,因此在接下来的一天中就会吃很多别的东西,往往导致体重增加。根据第三段可知两组女性所吃的酸奶卡路里相同(that contained exactly the same amount of calories),并非哪个热量多哪个少,也并非说吃了同等数量的酸奶,因此选项B和C都不对。实验结果表明食用低脂酸奶的人反而体重增加,因此D选项不对。本题只能选A。
文中第一句话就说:即使减少脂肪摄入量,肥胖依然是美国人面临的一个问题,以及接下来所举的例子都说明了通过摄入低脂食物的方法未必能减肥,因此选项A和D 都不对。通过第一段第三和第四句可知:美国人认为有必要知道各种食物所含热量,由此来决定食用什么以及多少食物。因此可推断选项C是正确的。
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