VOA常速英语2008年-Rat Study Links Weight Gain to Artificial Sweet

By Melinda Smith
Washington, DC
15 February 2008
 

Obesity¹ is becoming a worldwide problem, even in developing countries. But diet drinks and food prepared with sugar substitutes do not seem to help curb² people's appetites. Now a new study may provide some clues about the ineffectiveness of artificial sweeteners. VOA's Melinda Smith has details.

In the last four decades -- as cities grew larger and worldwide income rose -- the average diet around the world increased by at least 74 calories. A University of North Carolina study credited this caloric boost to the growing consumption of sugar and sugar substitutes. In that same period, U.S. consumption of sugar-free foods nearly doubled.

Whether you call them calorie free sweeteners, artificial sweeteners or sugar substitutes, many of us thought this tasty replacement³ was as good as the real thing.

Apparently⁴ we were wrong, says Professor Susan Swithers of Purdue University. She says, "It's temping to think that by simply consuming a food that has fewer calories, that body weight gain and food intake⁵ are automatically going to go down. Our data suggest that, in fact, the opposite might happen."

A Purdue University study was done on two groups of rats. One group was given artificially sweetened yogurt and the other group was given yogurt with glucose⁶, a natural sweetener high in calories. But rats given the artificial sweetener gained 20 percent more weight.

The researchers say the artificial sweetener somehow interrupts the body's ability to regulate or register the amount of calories it has consumed. As a result, metabolism⁷ slows down and does not burn as many calories.

Professor Swithers explains. "When they got a sweet-tasting food that didn't deliver those calories, they went and then overindulged in their regular food as a consequence."

Artificially sweetened soft drinks and fruit drinks make up a big share of the American diet. A medical consultant⁸ for the U.S. beverage⁹ industry, John Foreyt, says it is wrong to compare behavior of rats and people. "The bottom line is that we are not rats. You cannot extrapolate a study with rats to humans."

But a survey of people in 2005 found results similar to the Purdue study on rats. It showed a 41 percent weight gain among people who drank diet soft drinks. The Purdue researchers caution that switching to food and drink prepared with real sugar is still no substitute for cutting back on portions and filling up on exercise.

1 obesity   

n.肥胖，肥大

参考例句：

• One effect of overeating may be obesity.吃得过多能导致肥胖。
• Sugar and fat can more easily lead to obesity than some other foods.糖和脂肪比其他食物更容易导致肥胖。

2 curb   

n.场外证券市场，场外交易；vt.制止，抑制

参考例句：

• I could not curb my anger.我按捺不住我的愤怒。
• You must curb your daughter when you are in church.你在教堂时必须管住你的女儿。

3 replacement   

n.取代，替换，交换；替代品，代用品

参考例句：

• We are hard put to find a replacement for our assistant.我们很难找到一个人来代替我们的助手。
• They put all the students through the replacement examination.他们让所有的学生参加分班考试。

4 apparently   

adv.显然地；表面上，似乎

参考例句：

• An apparently blind alley leads suddenly into an open space.山穷水尽，豁然开朗。
• He was apparently much surprised at the news.他对那个消息显然感到十分惊异。

5 intake   

n.吸入，纳入；进气口，入口

参考例句：

• Reduce your salt intake.减少盐的摄入量。
• There was a horrified intake of breath from every child.所有的孩子都害怕地倒抽了一口凉气。

6 glucose   

n.葡萄糖

参考例句：

• I gave him an extra dose of glucose to pep him up.我给他多注射了一剂葡萄糖以增强他的活力。
• The doctor injected glucose into his patient's veins.医生将葡萄糖注入病人的静脉。

7 metabolism   

n.新陈代谢

参考例句：

• After years of dieting,Carol's metabolism was completely out of whack.经过数年的节食，卡罗尔的新陈代谢完全紊乱了。
• All living matter undergoes a process of metabolism.生物都有新陈代谢。

8 consultant   

n.顾问；会诊医师，专科医生

参考例句：

• He is a consultant on law affairs to the mayor.他是市长的一个法律顾问。
• Originally,Gar had agreed to come up as a consultant.原来，加尔只答应来充当我们的顾问。

9 beverage   

n.(水，酒等之外的)饮料

参考例句：

• The beverage is often colored with caramel.这种饮料常用焦糖染色。
• Beer is a beverage of the remotest time.啤酒是一种最古老的饮料。