2019年雅思考试考前阅读精品练习题3

相信很多同学都知道，阅读是我们提分比较容易的一项考察科目，所以我们在平时要加强对阅读的训练，今天小编就给大家整理了这篇阅读素材，在坦途网雅思考试频道还有很多相关的内容和考试资讯，现在我们就先来看一下这篇文章吧！

The discovery of the obesity gene in humans half a decade ago offered evidence that chronic weight gain is the consequence of a mismatch between nature and nurture. Simplistic explanations, such as blaming obesity on a drop in fat consumption, ignore scientific reality. In countries like India and China, obesity was virtually unknown until the introduction of a high-fat, western-style diet.

One well-known reason for this is that dietary fat converts to (转换为 )body fat more efficiently than does protein or carbohydrate, but recently scientists have uncovered what appears to be an equally important factor. Some researchers in universities are investigating the possibility that high levels of fat and fructose are mucking up(扰乱 ) our brain chemistry, and thereby muting the signals that would normally tell us to put down the fork. These signals are produced by peptides, which are regulated by a number of hormones. Under normal conditions these hormones help maintain a stable body weight by adjusting levels of the peptides that control eating. But a diet loaded with fat and fructose hampers the regulation of these hormones. Complicating matters still further is that the brain loses its ability to respond to these hormones as body fat increases -- so the obese are doubly penalized.

Other researchers are finding evidence that constant exposure to fat and sugar can cause some humans to crave (渴望)them as they do an addictive drug. A Princeton University psychologist recently showed that rats fed a high sugar diet were, when the sugar was removed, thrown into a state of anxiety similar to that seen in withdrawal from morphine or nicotine. Sarah Leibowitz, a neurobiologist, believes that frequent exposure to fatty foods may configure the brain to crave still more fat. She has shown in animal studies that galanin, a brain peptide that simulates eating behavior and decreases energy expenditure, increases when the animal eats a high-fat diet.

There are many factors contributing to the explosion of obesity in the United States, and the world, but the radical changes in the composition of our diet are first among them. While scientific work in this area is in its infancy, it's already clear that varying the amount of fat and other nutrients in the diet affects brain chemistry by activating certain genes, and this in turn directs our dietary preferences. By submitting ourselves to a steady dose of highly processed, sweet, high-fat foods, we have unwittingly entered into a dangerous experiment, the long term consequences of which are only now beginning to surface.

以上就是小编为大家整理的全部内容了，在一阅读素材里，我们不仅能练习我们的阅读能力，还可以积累素材，建立我们自己的素材库，经过量的积累，我们才会有质的飞跃，小编有也会继续为大家整理相关的内容，希望大家在最后雅思考试成绩查询结果出来的时候，大家都能看到满意的结果！