Danny Cahill stood, slightly dazed, in a blizzard ofconfetti as the audience screamed and his family ranon stage. He had won Season 8 of NBC’s realitytelevision show “The Biggest Loser,” shedding moreweight than anyone ever had on the program — anastonishing 239 pounds in seven months.
When he got on the scale for all to see that evening, Dec. 8, 2009, he weighed just 191pounds, down from 430. Dressed in a T-shirt and knee-length shorts, he was lean, athleticand as handsome as a model.
“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(jué)好極了。”
Cahill left the show’s stage in Hollywood and flew directly to New York to start a triumphal tourof the talk shows, chatting with Jay Leno, Regis Philbin and Joy Behar. As he heard from fans allover the world, his elation knew no bounds.
But in the years since, more than 100 pounds have crept back onto his 5-foot-11 framedespite his best efforts. In fact, most of that season’s 16 contestants have regained much ifnot all the weight they lost so arduously. Some are even heavier now.
Yet their experiences, while a bitter personal disappointment, have been a gift to science. Astudy of Season 8’s contestants has yielded surprising new discoveries about the physiologyof obesity that help explain why so many people struggle unsuccessfully to keep off the weightthey lose.
Kevin Hall, a scientist at a federal research center who admits to a weakness for reality TV, hadthe idea to follow the “Biggest Loser” contestants for six years after that victorious night. Theproject was the first to measure what happened to people over as long as six years after theyhad lost large amounts of weight with intensive dieting and exercise.
“It is frightening and amazing,” said Hall, an expert on metabolism at the National Institute ofDiabetes and Digestive and Kidney Diseases, which is part of the National Institutes of Health. “Iam just blown away.”
“這令人恐懼和驚訝,”霍爾說(shuō)。他是國(guó)家衛(wèi)生研究院(National Institutes of Health)下屬的國(guó)家糖尿病、消化系統(tǒng)疾病和腎病研究所(National Institute of Diabetes and Digestive and Kidney Diseases)的新陳代謝專家。“這令我大為震驚。”
It has to do with resting metabolism, which determines how many calories a person burns whenat rest. When the show began, the contestants, though hugely overweight, had normalmetabolisms for their size, meaning they were burning a normal number of calories for people oftheir weight. When it ended, their metabolisms had slowed radically and their bodies were notburning enough calories to maintain their thinner sizes.
Researchers knew that just about anyone who deliberately loses weight — even if they start ata normal weight or even underweight — will have a slower metabolism when the diet ends. Sothey were not surprised to see that “The Biggest Loser” contestants had slow metabolismswhen the show ended.
What shocked the researchers was what happened next: As the years went by and thenumbers on the scale climbed, the contestants’ metabolisms did not recover. They becameeven slower, and the pounds kept piling on. It was as if their bodies were intensifying theireffort to pull the contestants back to their original weight.
Cahill was one of the worst off. As he regained more than 100 pounds, his metabolism slowedso much that, just to maintain his current weight of 295 pounds, he now has to eat 800calories a day less than a typical man his size. Anything more turns to fat.
The struggles the contestants went through help explain why it has been so hard to makeheadway against the nation’s obesity problem, which afflicts more than a third of Americanadults. Despite spending billions of dollars on weight-loss drugs and dieting programs, even themost motivated are working against their own biology.
Their experience shows that the body will fight back for years. And that, said Dr. MichaelSchwartz, an obesity and diabetes researcher who is a professor of medicine at the Universityof Washington, is “new and important.”
他們的經(jīng)驗(yàn)表明,身體會(huì)反抗很多年。肥胖和糖尿病研究者、華盛頓大學(xué)(University of Washington)醫(yī)學(xué)教授邁克爾·施瓦茨博士(Michael Schwartz)說(shuō),這一點(diǎn)是“新發(fā)現(xiàn),也很重要”。
“The key point is that you can be on TV, you can lose enormous amounts of weight, you cango on for six years, but you can’t get away from a basic biological reality,” said Schwartz, whowas not involved in the study. “As long as you are below your initial weight, your body is goingto try to get you back.”
The study’s findings, to be published on Monday in the journal Obesity, are part of a scientificpush to answer some of the most fundamental questions about obesity. Researchers arefiguring out why being fat makes so many people develop diabetes and other medicalconditions, and they are searching for new ways to block the poison in fat. They are startingto unravel the reasons bariatric surgery allows most people to lose significant amounts ofweight when dieting so often fails. And they are looking afresh at medical care for obese people.
The hope is that this work will eventually lead to new therapies that treat obesity as a chronicdisease and can help keep weight under control for life.
Most people who have tried to lose weight know how hard it is to keep the weight off, but manyblame themselves when the pounds come back. But what obesity research has consistentlyshown is that dieters are at the mercy of their own bodies, which muster hormones and analtered metabolic rate to pull them back to their old weights, whether that is hundreds ofpounds more or that extra 10 or 15 that many people are trying to keep off.
There is always a weight a person’s body maintains without any effort. And while it is not knownwhy that weight can change over the years — it may be an effect of aging — at any point, thereis a weight that is easy to maintain, and that is the weight the body fights to defend. Finding away to thwart these mechanisms is the goal scientists are striving for. First, though, they aretrying to understand them in greater detail.
Dr. David Ludwig, the director of the New Balance Foundation Obesity Prevention Center atBoston Children’s Hospital, who was not involved in the research, said the findings showed theneed for new approaches to weight control. He cautioned that the study was limited by itssmall size and the lack of a control group of obese people who did not lose weight. But, headded, the findings made sense.
“This is a subset of the most successful” dieters, he said. “If they don’t show a return tonormal in metabolism, what hope is there for the rest of us?”
Still, he added, “that shouldn’t be interpreted to mean we are doomed to battle our biology orremain fat. It means we need to explore other approaches.”
All this does not mean that modest weight loss is hopeless, experts say. Individuals responddifferently to diet manipulations — low-carbohydrate or low-calorie diets, for example — andto exercise and weight-loss drugs, among other interventions.
But Ludwig said that simply cutting calories was not the answer. “There are no doubtexceptional individuals who can ignore primal biological signals and maintain weight loss forthe long term by restricting calories,” he said, but he added that “for most people, thecombination 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.”
Cahill knows that now. And with his report from Hall’s group showing just how much hismetabolism had slowed, he stopped blaming himself for his weight gain.