努力減肥後體重反彈 那不是你的錯

Danny Cahill stood, slightly dazed, in a blizzard of confetti as the audience screamed and his family ran on stage. He had won Season 8 of NBC’s reality television show “The Biggest Loser,” shedding more weight than anyone ever had on the program — an astonishing 239 pounds in seven months.

丹尼·卡希爾(Danny Cahill)站在漫天的五彩紙屑中，微微有點懵，觀衆們在尖叫，他的家人飛奔上臺。他獲得了NBC頻道電視真人秀節目《超級減肥王》(The Biggest Loser)第8季的冠軍，在七個月時間裏驚人地減掉了239磅（約217斤），超過了節目的其他所有參與者。

When he got on the scale for all to see that evening, Dec. 8, 2009, he weighed just 191 pounds, down from 430. Dressed in a T-shirt and knee-length shorts, he was lean, athletic and as handsome as a model.

2009年12月8日的那個晚上，他上秤讓所有人看到，他從430磅（約390斤）減到了191磅（約173斤）。當時，他穿着T恤和及膝短褲，看起來精瘦強壯，和模特一樣帥。

“I’ve got my life back,” he declared. “I mean, I feel like a million bucks.”

“我重新找回了生活，”他宣稱，“我感覺好極了。”

Cahill left the show’s stage in Hollywood and flew directly to New York to start a triumphal tour of the talk shows, chatting with Jay Leno, Regis Philbin and Joy Behar. As he heard from fans all over the world, his elation knew no bounds.

卡希爾離開好萊塢那個節目的舞臺，直接飛到紐約，開始進行一系列勝利者的脫口秀，接受傑·雷諾(Jay Leno)、裏吉斯·菲爾賓(Regis Philbin)和喬伊·貝哈爾(Joy Behar)的採訪。他收到世界各地粉絲們的來信，得意無比。

But in the years since, more than 100 pounds have crept back onto his 5-foot-11 frame despite his best efforts. In fact, most of that season’s 16 contestants have regained much if not all the weight they lost so arduously. Some are even heavier now.

然而在那之後，雖然盡了最大努力，身高5英尺11英寸（約1.8米）的他還是慢慢長了逾100磅（約90斤）。實際上，那一季的16名參賽者辛苦減掉體重之後，多數人有反彈，哪怕不是完全長回了減掉的體重。有些人的體重甚至超過了上節目前。

Yet their experiences, while a bitter personal disappointment, have been a gift to science. A study of Season 8’s contestants has yielded surprising new discoveries about the physiology of obesity that help explain why so many people struggle unsuccessfully to keep off the weight they lose.

這些經歷對他們個人來說雖然意味着苦澀的失望，但對科學來說，卻是天賜良機。對第8季參賽者的研究得出了令人驚訝的新發現，讓我們更瞭解肥胖的生理機能，並有助於解釋爲什麼那麼多人減肥之後無法保持。

Kevin Hall, a scientist at a federal research center who admits to a weakness for reality TV, had the idea to follow the “Biggest Loser” contestants for six years after that victorious night. The project was the first to measure what happened to people over as long as six years after they had lost large amounts of weight with intensive dieting and exercise.

凱文·霍爾(Kevin Hall)是一家聯邦研究中心的科學家，他承認自己酷愛電視真人秀。在卡希爾獲勝之後，他產生了一個想法：跟蹤研究《超級減肥王》的參賽者六年。人們在通過高強度飲食控制和鍛鍊實現大幅減輕體重之後，接下來長達六年的時間裏會怎麼樣，這是第一個針對該問題的跟蹤研究。

The results, the researchers said, were stunning. They showed just how hard the body fights back against weight loss.

研究者說，結果令人震驚。結果表明，身體對體重減輕的反抗非常強烈。

“It is frightening and amazing,” said Hall, an expert on metabolism at the National Institute of Diabetes and Digestive and Kidney Diseases, which is part of the National Institutes of Health. “I am just blown away.”

“這令人恐懼和驚訝，”霍爾說。他是國家衛生研究院(National Institutes of Health)下屬的國家糖尿病、消化系統疾病和腎病研究所(National Institute of Diabetes and Digestive and Kidney Diseases)的新陳代謝專家。“這令我大爲震驚。”

It has to do with resting metabolism, which determines how many calories a person burns when at rest. When the show began, the contestants, though hugely overweight, had normal metabolisms for their size, meaning they were burning a normal number of calories for people of their weight. When it ended, their metabolisms had slowed radically and their bodies were not burning enough calories to maintain their thinner sizes.

這與靜止代謝有關，也就是一個人在靜止狀態下消耗的熱量。節目開始時，參賽者雖然嚴重超重，但是新陳代謝水平對他們的身材來講是正常的，也就是說，他們靜止時燃燒的熱量對於他們那個體重的人來說，屬於正常值。節目結束時，他們的新陳代謝急劇減緩，他們的身體沒有消耗足夠多的熱量來保持較瘦的體型。

Researchers knew that just about anyone who deliberately loses weight — even if they start at a normal weight or even underweight — will have a slower metabolism when the diet ends. So they were not surprised to see that “The Biggest Loser” contestants had slow metabolisms when the show ended.

研究者已經知道，任何故意減輕體重的人——即使他們本來是正常體重或者體重偏低——在節食結束時，新陳代謝都會變慢。所以，他們對《超級減肥王》的參賽者在節目結束時新陳代謝減緩並不感到意外。

What shocked the researchers was what happened next: As the years went by and the numbers on the scale climbed, the contestants’ metabolisms did not recover. They became even slower, and the pounds kept piling on. It was as if their bodies were intensifying their effort to pull the contestants back to their original weight.

令研究者們感到吃驚的是之後發生的事：隨着時間流逝，體重增加，參賽者的新陳代謝水平沒有恢復，甚至變得更慢了，於是體重也繼續增加。好像他們的身體在努力讓他們恢復到原來的體重。

Cahill was one of the worst off. As he regained more than 100 pounds, his metabolism slowed so much that, just to maintain his current weight of 295 pounds, he now has to eat 800 calories a day less than a typical man his size. Anything more turns to fat.

卡希爾是情況最糟的一個。他的體重增加了逾100磅，新陳代謝變得非常緩慢，以至於爲了維持目前295磅的體重，他每天不得不比這個體重的普通人少攝入800卡路里。多吃一口都長肉。

The struggles the contestants went through help explain why it has been so hard to make headway against the nation’s obesity problem, which afflicts more than a third of American adults. Despite spending billions of dollars on weight-loss drugs and dieting programs, even the most motivated are working against their own biology.

這些參賽者所經歷的困難有助於解釋爲什麼美國的肥胖問題很難取得進展。超過三分之一的美國成年人有肥胖問題。數十億美元被花在減肥藥和減肥項目上面，但是連最積極的減肥者也是在與自身的生物機制對抗。

Their experience shows that the body will fight back for years. And that, said Dr. Michael Schwartz, an obesity and diabetes researcher who is a professor of medicine at the University of Washington, is “new and important.”

他們的經驗表明，身體會反抗很多年。肥胖和糖尿病研究者、華盛頓大學(University of Washington)醫學教授邁克爾·施瓦茨博士(Michael Schwartz)說，這一點是“新發現，也很重要”。

“The key point is that you can be on TV, you can lose enormous amounts of weight, you can go on for six years, but you can’t get away from a basic biological reality,” said Schwartz, who was not involved in the study. “As long as you are below your initial weight, your body is going to try to get you back.”

“重點是，你能上電視，你能把體重減輕很多，你能堅持六年，但你無法擺脫基本的生物學事實，”施瓦茨說。他沒有參與這項研究。“只要低於原來的體重，你的身體就會努力讓你恢復。”

The study’s findings, to be published on Monday in the journal Obesity, are part of a scientific push to answer some of the most fundamental questions about obesity. Researchers are figuring out why being fat makes so many people develop diabetes and other medical conditions, and they are searching for new ways to block the poison in fat. They are starting to unravel the reasons bariatric surgery allows most people to lose significant amounts of weight when dieting so often fails. And they are looking afresh at medical care for obese people.

這項研究的結果將於週一發表在《肥胖》雜誌(Obesity)上。它是爲回答一些最基本的肥胖問題而進行的科學研究的一部分。研究者們正在努力弄清爲什麼肥胖讓這麼多人患上糖尿病或出現其他健康問題，他們也在尋找阻斷脂肪中有害物質的新方法。他們開始揭示，爲什麼肥胖手術能讓大部分人體重減輕很多而節食卻經常失敗。他們還在重新審視對超重者的醫療護理。

The hope is that this work will eventually lead to new therapies that treat obesity as a chronic disease and can help keep weight under control for life.

他們希望，這項工作將最終讓我們找到新的治療方法，把肥胖作爲一種慢性病加以治療，並且終生控制體重。

Most people who have tried to lose weight know how hard it is to keep the weight off, but many blame themselves when the pounds come back. But what obesity research has consistently shown is that dieters are at the mercy of their own bodies, which muster hormones and an altered metabolic rate to pull them back to their old weights, whether that is hundreds of pounds more or that extra 10 or 15 that many people are trying to keep off.

大部分試過減肥的人都知道保持減輕後的體重有多難，但是很多人在體重又增加時會怪自己。但是，肥胖研究一再表明，節食者受制於自己的身體，它通過調節激素和代謝率，讓他們恢復原來的體重，不管是幾百磅，還是很多人想努力避免長回去的那10磅或15磅。

There is always a weight a person’s body maintains without any effort. And while it is not known why that weight can change over the years — it may be an effect of aging — at any point, there is a weight that is easy to maintain, and that is the weight the body fights to defend. Finding a way to thwart these mechanisms is the goal scientists are striving for. First, though, they are trying to understand them in greater detail.

每個人都有一個不必費力就能維持的體重。雖然不知道這個數字爲什麼會隨着時間發生變化——可能是年齡增長的結果——但是在任何一個時間點，總有一個容易保持的體重，那也就是身體努力保衛的體重。找到對抗這一機制的方法是科學家努力追求的目標。不過，他們首先要努力瞭解更多細節。

Dr. David Ludwig, the director of the New Balance Foundation Obesity Prevention Center at Boston Children’s Hospital, who was not involved in the research, said the findings showed the need for new approaches to weight control. He cautioned that the study was limited by its small size and the lack of a control group of obese people who did not lose weight. But, he added, the findings made sense.

波士頓兒童醫院(Boston Children’s Hospital)新平衡基金會肥胖預防中心(New Balance Foundation Obesity Prevention Center)的主管大衛·路德維希博士(David Ludwig)說，這些發現表明，需要尋找控制體重的新方法。他沒有參與這項研究。他提醒說，這項研究的侷限性在於規模小，沒有對照組，也就是沒有一組未參加減肥的肥胖者。不過，他補充說，這些發現說得通。

“This is a subset of the most successful” dieters, he said. “If they don’t show a return to normal in metabolism, what hope is there for the rest of us?”

他說，“他們是最成功的”減肥者，“如果他們的新陳代謝水平沒有恢復正常，我們剩下這些人還有什麼希望呢”。

Still, he added, “that shouldn’t be interpreted to mean we are doomed to battle our biology or remain fat. It means we need to explore other approaches.”

不過，他補充說，“這不應該被理解爲，我們註定要對抗自身的生物機制，或者就只能繼續肥胖。而應該被理解爲，我們需要探索其他方法。”

All this does not mean that modest weight loss is hopeless, experts say. Individuals respond differently to diet manipulations — low-carbohydrate or low-calorie diets, for example — and to exercise and weight-loss drugs, among other interventions.

專家們說，所有這些並不意味着適度減肥毫無希望。每個人對飲食控制（比如低碳水化合物或低熱量飲食）以及鍛鍊和減肥藥物等各種干預的反應是不同的。

But Ludwig said that simply cutting calories was not the answer. “There are no doubt exceptional individuals who can ignore primal biological signals and maintain weight loss for the long term by restricting calories,” he said, but he added that “for most people, the combination of incessant hunger and slowing metabolism is a recipe for weight regain — explaining why so few individuals can maintain weight loss for more than a few months.”

不過，路德維希說，僅僅減少熱量攝入不是問題的答案。他說，“毫無疑問，有些例外的人能夠不理會基本的生物信號，通過控制熱量攝入長期保持體重減輕”，但是，“對大部分人來說，無休止的飢餓感和不斷放緩的代謝加在一起，會導致體重重新增加，這就能解釋爲什麼很少有人能保持體重減輕超過幾個月”。

Cahill knows that now. And with his report from Hall’s group showing just how much his metabolism had slowed, he stopped blaming himself for his weight gain.

卡希爾現在知道了。霍爾團隊關於他的報告表明，他的代謝減緩了很多，所以他不再因爲體重增加而責怪自己了。

“That shame that was on my shoulders went off,” he said.

“我揹負的羞恥感消失了，”他說。