為何體重反彈容易，減肥卻這么困難?發(fā)表于《肥胖》(Obesity)雜志上的近期研究表明，實(shí)際上我們的身體機(jī)制抗拒體重減輕。節(jié)食時(shí)，人體的靜息代謝率降低，當(dāng)我們運(yùn)動(dòng)量很少時(shí)，燃燒的熱量就很少。這項(xiàng)研究的發(fā)起人表示減肥需要“機(jī)警地與代謝適應(yīng)過程作斗爭(zhēng)”。
The study followed 14 participants of the US version of the TV show The Biggest Loser. The researchers found that, after six years, all but one of the contestants in their study had regained weight. On average, they weighed 20st 10lb (131.5kg), compared with the average starting weight of 23st 6lb (149kg) and the 14st 4lb (91kg) at which they finished the show.
這項(xiàng)研究跟蹤調(diào)查了美國版的電視節(jié)目《超級(jí)減肥王》(The Biggest Loser)中的14位參與者。研究人員發(fā)現(xiàn)，六年后，這項(xiàng)研究中除一位參與者外，其他所有人的體重都反彈了。他們現(xiàn)在的平均體重是290磅(131.5千克)，而剛參加節(jié)目時(shí)的平均體重是328磅(149千克)，節(jié)目結(jié)束時(shí)的平均體重是200磅(91千克)。
The solution
解決方法.
Six years is a long time, and being, on average, 2st 10lb (17kg) lighter is not insignificant. But the odds were stacked against the participants. The study showed that, before the competition, the group burned a daily average of 2,600 calories at rest, but this fell to around 2,000 calories a day when it finished. Six years later, instead of creeping back up to its normal level, their resting rate had slowed further to 1,900 calories a day. On average, the resting metabolic rate was 500 calories a day less than you would expect for the age and body composition of the person. So, the contestants had to eat less to stay at their lower weight. While researchers knew that dieting reduces the resting metabolic rate to save energy, this study shows how savagely your body subverts weight loss.
六年的時(shí)間很長，平均每個(gè)人減重38磅(17kg)，其效果并不顯著。但參與者減肥成功的機(jī)會(huì)不大。研究表明，在減肥比賽開始前，這群參與者每天不活動(dòng)時(shí)平均能消耗2600卡。但節(jié)目結(jié)束時(shí)，他們每天不活動(dòng)時(shí)大約只能消耗2000卡了。六年后，他們的靜息代謝率進(jìn)一步放緩，每天只能消耗1900卡，而沒有回升到正常水平�？紤]每個(gè)人的年齡和身體組成，他們平均的靜息代謝率比期望的低500卡。所以，參與者必須減少食物攝入以保持較低體重。研究人員知道節(jié)食會(huì)降低身體的靜息代謝率以儲(chǔ)存能量，而這項(xiàng)研究表明了我們的身體機(jī)制瘋狂地抗拒體重減少。
This was a small study without controls, though, and weight loss is influenced by factors such as genetics and hormones. Other studies show that some people are less affected than others. The report on The Biggest Loser participants cites another study showing that obese people who have weight-loss surgery seem to escape this metabolic adaptation. Somehow, the body resets to a new normal weight and the resting metabolic rate doesn’t fall. For the rest of us, being vigilant about what we eat, and building up muscle mass (which is lost with age) through aerobic exercise and strength training are the only ways to fight back.
盡管這是一項(xiàng)沒有對(duì)照組的小型研究，但減肥會(huì)受到遺傳和激素等多種因素的影響。其他研究表明，一些人受到遺傳和激素的影響較小。有關(guān)《超級(jí)減肥王》參與者的報(bào)告引用了另一項(xiàng)研究。該研究表明，做過減肥手術(shù)的肥胖者似乎能夠擺脫代謝適應(yīng)過程。不知為何，他們的身體能夠適應(yīng)新的正常體重，靜息代謝率也不會(huì)降低。我們其余的人，必須要對(duì)自己的飲食特別上心，通過有氧鍛煉和力量訓(xùn)練的方法練出肌肉群(隨著年齡增長會(huì)喪失)，這是防止體重反彈的唯一方法。
Your resting metabolic rate determines only a proportion of your energy expenditure. If you burn off more calories than you eat, you will lose weight. Other research suggests that reducing calories by 20% and doing moderate exercise for 20 minutes a day will keep weight off.
靜息代謝率只能決定你的一部分能量消耗。如果你消耗的熱量比攝入的多，你的體重就會(huì)減輕。其他研究表明，每天少攝入20%的熱量，適度鍛煉20分鐘能夠減肥。
