垃圾食品热量高 不知不觉长体重
文章来源: 文章作者: 发布时间:2007-05-28 07:15 字体: [ ]  进入论坛

Junk food is fooling people into overeating

Fast food restaurants are feeding the obesity1 epidemic2 by tricking people into eating many more calories than they mean to, an important study has shown.

Typical menus at McDonald's, KFC and Burger King contain 65 per cent more calories per bite than standard British meals, making it far too easy ffor customers to overindulge without realising it.

The high "energy density3" of junk food - the amount of calories it contains in relation to its weight - throws the brain's appetite control system into confusion, as this is based on the size of a portion rather than its energy content.

The critical role of energy density in obesity has been revealed by Andrew Prentice, Professor of International Nutrition at the London School of Hygiene4 and Tropical Medicine, and Susan Jebb, of the Medical Research Council Human Nutrition Centre in Cambridge.

In a study published in the journal Obesity Reviews, they calculated the average energy density of menus at McDonald's, KFC and Burger King, using nutritional5 data from the fast food chains' websites.

The average energy density of these restaurants' meals was 263 calories per 100 grams, 65 per cent more than the density of the average British diet and more than twice that of a recommended healthy diet. This means that a person eating a Big Mac and fries would consume almost twice as many calories as someone eating the same weight of pasta and salad.

Professor Prentice said that the human appetite encouraged people to eat a similar bulk of food, regardless of its calorific value. This left regular consumers of fast food prone6 to "accidental" obesity, in which they grew fat while eating portions they did not consider large.

Professor Prentice added: "Since the dawn of agriculture, the systems regulating human appetites have evolved for the low-energy diet still consumed in rural areas of the developing world, where obesity is almost non-existent. Our system of appetite control is completely unpicked by the junk food diet."

When fast food is eaten often, even small miscalculations of portion size can have major effects, the study found. If a person eats 200g extra of fast food with a density of 1,200kJ per 100g just twice a week, he would consume an extra 250,000kJ a year. This is enough to put on almost 8kg of fat.

Fast food outlets7 should reduce the energy density of their menus as well as their portion sizes, the scientists said.












1 obesity Dv1ya     
  • 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 epidemic 5iTzz     
  • That kind of epidemic disease has long been stamped out.那种传染病早已绝迹。
  • The authorities tried to localise the epidemic.当局试图把流行病限制在局部范围。
3 density rOdzZ     
  • The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
  • The region has a very high population density.该地区的人口密度很高。
4 hygiene Kchzr     
n.健康法,卫生学 (a.hygienic)
  • Their course of study includes elementary hygiene and medical theory.他们的课程包括基础卫生学和医疗知识。
  • He's going to give us a lecture on public hygiene.他要给我们作关于公共卫生方面的报告。
5 nutritional 4HRxN     
  • A diet lacking in nutritional value will not keep a person healthy.缺乏营养价值的饮食不能维持人的健康。
  • The labels on food products give a lot of information about their nutritional content.食品上的标签提供很多关于营养成分的信息。
6 prone 50bzu     
  • Some people are prone to jump to hasty conclusions.有些人往往作出轻率的结论。
  • He is prone to lose his temper when people disagree with him.人家一不同意他的意见,他就发脾气。
7 outlets a899f2669c499f26df428cf3d18a06c3     
n.出口( outlet的名词复数 );经销店;插座;廉价经销店
  • The dumping of foreign cotton blocked outlets for locally grown cotton. 外国棉花的倾销阻滞了当地生产的棉花的销路。 来自《简明英汉词典》
  • They must find outlets for their products. 他们必须为自己的产品寻找出路。 来自《现代汉英综合大词典》