研究表明:晚睡容易讓你的體重增加!

There may be a link between later bedtimes and weight gain, new research suggests.
新研究表明，晚睡與體重增加之間可能存在關聯。

Researchers studied 3,342 adolescents starting in 1996, following them through 2009. At three points over the years, all reported their normal bedtimes, as well as information on fast food consumption, exercise and television time. The scientists calculated body mass index at each interview.
從1996年至2009年，3342名青少年接受了研究人員的隨訪，並分別在這期間的三個時間點上報告了自己平時的就寢時間、看電視時間以及食用快餐和鍛鍊的情況。在每次訪談時，科學家們均計算了各位參與者的身體質量指數(B.M.I.)。

After controlling for age, sex, race, ethnicity and socioeconomic status, the researchers found that each hour later bedtime during the school or workweek was associated with about a two-point increase in B.M.I.
在對年齡、性別、種族、民族和社會經濟地位進行校正後，研究人員發現，在校時或在每週的工作日期間，參與者每晚睡一小時與其B.M.I.約增加2個點相關。

The effect was apparent even among people who got a full eight hours of sleep, and neither TV time nor exercise contributed to the effect. But fast food consumption did.
即使在能睡足8小時的人當中，這種效應依然很明顯，且它與看電視時間或鍛鍊均無關，但與食用快餐有關。

The study, in the October issue of Sleep, raises questions, said the lead author, Lauren D. Asarnow, a graduate student at the University of California, Berkeley.
該研究發表在《睡眠》雜誌的十月刊上。其主要作者，加州大學伯克利分校的研究生勞倫·D·奧薩諾表示，該研究提出了一些有待解決的問題。

"First, what is driving this relationship?" she said. "Is it metabolic changes that happen when you stay up late? And second, if we change sleep patterns, can we change eating behavior and the course of weight change?"
"首先，這種關聯背後的推動力是什麼？是因爲當你熬夜時，新陳代謝發生了改變？"她說。"第二，如果改變了睡眠習慣，那我們是否可以改變飲食行爲和體重變化的過程？"

The scientists acknowledge that their study had limitations. Their sleep data depended on self-reports, and they did not have complete diet information. Also, they had no data on waist circumference, which, unlike B.M.I., can help distinguish between lean muscle and abdominal fat.
科學家們承認他們的研究存在一定的侷限性。他們的睡眠數據依賴於自我報告，也沒能獲得完整的飲食信息。此外，他們沒有參與者的腰圍數據。而腰圍數據較之B.M.I.有一個優點就是它有助於區分肌肉和腹部脂肪。