一、垃圾食品对你健康不利
Junk food: 包括 快餐食品(Fast food)、油炸食品(Fried food)、用化学方式加工过的食品(Processed food)和吃了令人肥胖的食品(Fattening food)。 Eating junk food is unhealthyIt is unhealthy to have junk food
二、Junk food is fooling people into overeating
Fast food restaurants are feeding the obesity epidemic 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 density" 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 Hygiene 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 nutritional 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 prone 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 outlets should reduce the energy density of their menus as well as their portion sizes, the scientists said.
一项重要的研究显示:快餐店引诱人们摄入的卡路里远远超过他们实际所需要的量,结果助长了肥胖病的流行。
麦当劳、肯德基和汉堡王的代表食品每一口的卡路里含量都比普通的西餐高出65%,让消费者们很容易就在不知不觉中摄入了过多的卡路里。
垃圾食品含有很高的“能量密度”,即食物重量和卡路里含量的比例。垃圾食品往往使大脑的食欲控制系统陷入混乱,因为控制系统判断的标准是食物份量的大小而不是热量含量的高低。
伦敦公共医学与热带医学学院的国际营养学教授安德鲁·普伦蒂塞和剑桥大学医学研究学会人类营养研究中心的苏姗·杰布已经揭示了能量密度在导致肥胖中的关键性作用。
《肥胖评论》杂志发表了他们的研究结果,他们通过快餐连锁网站上的营养数据计算了麦当劳、肯德基和汉堡王食品的平均能量密度。
这些快餐店食品的平均能量密度是每一百克263卡路里,比英国日常饮食的能量密度高出65%,是推荐的健康饮食能量密度的两倍多。这意味着吃一个巨无霸和炸薯条所摄入的卡路里差不多是吃同样重量的意大利面和色拉所摄入热量的两倍。
普伦蒂塞教授说人类的食欲诱使他们摄入相似体积的食物,而不顾食物的卡路里含量。这就使得那些经常吃快餐的人在不经意间就变胖了,而他们自己却并没觉得吃的特别多。
普伦蒂塞教授补充说:“从农业产生以来,人类的食欲调节系统不断向低能量进化。在发展中国家的农村,人们饮食中热量的含量还是很低的,在这些地方,肥胖病几乎不存在。我们的食欲控制系统完全被垃圾食品搞乱了。”
研究发现:如果你经常吃快餐食品,即使份量上很小的差异都会造成很大的影响。如果一个人每周两次多摄入200克能量密度为1200千焦/百克的快餐食品,他每年多摄入的热量就会达到25万千焦,这足以增加近8千克脂肪。
科学家们指出,快餐店不仅要降低食品的能量密度,而且要缩小食品的体积。
三、Is "low fat" always a good thing? Is a vegetarian dish always healthy? There are lots of myths and old wives' tales about food. Check out the following popular beliefs and challenge your assumptions.
False: If the label says "low fat" or 'reduced fat' then the product will always be a healthy choice.
To claim that a product is "reduced fat" the amount of fat must be at least 30% lower than standard products. But these types of foods tend to be high in fat and energy in the first place, so the "reduced fat" version can still have quite high amounts of both.
Foods labelled "low fat" or "reduced fat" aren't necessarily low in energy. The fat is replaced by other ingredients, so the product can end up with the same or an even higher energy (calorie) content.
Also, if you're tempted to use more of a reduced-fat product than you would of the full-fat version, you might end up having the same, or even more, fat and energy.
False: If you want to have the healthier option it's best to choose a vegetarian dish.
Some vegetarian dishes contain a lot of fat, especially if they're made with lots of cheese, oil, pastry or creamy sauces, or if they've been fried. So they aren't necessarily a healthy option.
In fact, red meat can be low in fat if it's lean and all the visible fat has been removed. Other low-fat options are chicken without the skin, and fish, if they've been cooked without too much fat.
But it's always a good idea to have some vegetables with your meal because we should be eating at least five portions of a variety of fruit and vegetables a day as part of a healthy balanced diet.
False: Drinking ice water helps to lose weight.
Drinking water is always good for weight loss, but this concept is related to the idea that if you drink ice water, your body has to burn calories warming it up.
Technically correct, but the number of calories you burn are really tiny. It's about 1 calorie per ounce of ice water to warm it up. We would think it would take more calories to heat up the water, but it doesn't.
So, drink water, but only ice water if you like it. Of course, you also don't cancel out the calories of an iced beverage that has calories because it's cold (like soda or juice), although that would be nice!
False: Canned food is not good for health.
In many respects this can be true for canned meat rather than canned fish. Long heat treatment makes even large fish bones soft and edible, thus providing an additional source for calcium intake, which is beneficial for our skeleton. Daily recommendation of calcium is approximately 1,500 mg, both for men or women, young or old.
False: It is unwise to swim within one hour of eating. 。
This myth dates half a century back when the American Red Cross has published an instruction on life-saving saying that swimming immediately after meal may cause stomach cramps and even death. But later this theory was questioned. Many swimmers assert that they usually cover long distances during training sessions immediately after meal.
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