愛薇塔樂學英文

Eat less and exercise more - it has long been the mantra for shedding those extra pounds. But now it seems that all the hard work may have been in vain.

Scientists say there are ten other reasons why people just keep getting bigger. They claim that sleeping habits, central heating, medicines and even some pollutants can play a role in weight gain.

Traditionally, health practitioners have focused on diet and exercise - and a large dose of willpower - to treat the problem.

However the scientists from top U.S. and Canadian universities say that these other factors must be considered.

Lack of sleep could be partly to blame. In recent years, the average night's sleep has dropped from nine hours to just seven.

Sleep deprivation alters levels of the hormones that regulate food intake and body fat and increase hunger and appetite.

If it is too hot or too cold, we burn calories to cool down or heat up. But if the temperature is just right, the calories may be turned into body fat instead.

Those who take beta-blockers to control their blood pressure can often put on 3lb. Similarly, studies have shown that going on the Pill can add 11lb to a woman's weight.

Mother Nature may also be to blame, with our body shape being partly inherited. The overweight are also more likely to settle with partners of a similar size, and their children are more likely to be obese.

And the use of pollutants is on the rise, say the researchers. The manmade chemicals in pesticides and plastics can interfere with our hormones and lead to weight gain.

Your mother's age and your weight at birth are also important, with older women more likely to have obese children and underweight babies having a bigger chance of being obese in later life.

We also tend to put on weight as we get older. Finally, giving up smoking can also help pile on the pounds.

The scientists from Yale, Cornell and Johns Hopkins said there was only 'circumstantial' evidence supporting poor diet and lack of exercise as the main causes of obesity.

Ten other factors behind the flab:

Sleep - Too little increases appetite 
Medicine - Many modern medicines lead to us putting on weight 

Mother's age - Older women are more likely to have obese children 

Choice of partner - Overweight people tend to pair with each other - and have overweight children 

Heating and air conditioning - 'Comfortable' temperatures stop us from burning off fat 

Genes - Body shape may be partly inherited 

Giving up smoking - Nicotine suppresses the appetite 

Manmade chemicals - Some chemicals interfere with hormones that keep fat levels low 

Weight at birth - Underweight babies have a bigger risk of obesity 

Getting older - Weight tends to increase with age

“少吃點，多運動”--這一直是肥胖者的減肥“座右銘”。但現在看來，所有的努力都可能白費了。

科學家們說，另有十條原因可以解釋人們為什麼不停的變胖。他們說，體重增加與睡眠習慣、中央供暖、藥物、甚至某些污染物都有關。

針對肥胖問題，健康學家們一直強調飲食和運動，還有堅強的毅力。

然而，美國和加拿大一些名牌大學的科學家們說，以下這些因素也一定要考慮在內。

缺乏睡眠在一定程度上會導致肥胖。近幾年，人們晚上的平均睡眠從9個小時下降到了7個小時。

缺乏睡眠會改變體內控制食物攝取和體脂肪的激素水準，增加饑餓感，促進食欲。

如果天氣太熱或太冷，體內熱量的燃燒會使人體降溫或升溫。但如果溫度適當，體內的熱量則會轉化為脂肪。

吃β-受體阻滯藥控制血壓的人體重常會增加3磅。此外，研究表明，服用口服避孕藥的女性體重會增加11磅。

自然力量也是個因素。人的體型一部分由遺傳因素決定。肥胖者往往會找一個和自己體型差不多的配偶，這樣，他們的孩子肥胖的可能性就較大。

研究人員們說，如今污染物的使用越來越多。殺蟲劑和塑膠中所含的人造化學物質會影響我們體內的激素水準，從而導致肥胖。

母親的年齡和嬰兒出生時的體重也很重要。年齡偏大的女性生出肥胖孩子的幾率較大，出生時體重不足的嬰兒今後變肥胖的可能性也較大。

此外，隨著我們年齡的增長，體重也會增加。最後一點，戒煙也會使體重增加。

耶魯大學、康奈爾大學和約翰斯·霍普金斯大學的科學家們說，只有一些間接證據表明不健康的飲食和缺乏運動是肥胖的主要誘因。

引發肥胖的另外十大原因如下：

睡眠--睡眠太少使胃口大增

藥物--很多現代藥物會導致體重增加

母親的年齡--年齡偏大的女性易生出肥胖的孩子

擇偶--肥胖者之間容易結為伴侶，這會導致他們的孩子肥胖

供暖和空調--舒適的溫度會阻礙體內脂肪的燃燒

基因--體型一部分由遺傳因素決定

戒煙--尼古丁能抑制食欲

人造化學物質--有些化學物質會影響體內控制脂肪水準的激素

出生時的體重--體重不足的嬰兒變肥胖的可能性較大

年齡增長--體重隨著年齡的增長而增加