為什么運(yùn)動不能幫所有人甩掉脂肪

Exercising but Gaining Weight

為什么運(yùn)動不能幫所有人甩掉脂肪

Exercise has innumerable health benefits, but losing weight may not be among them. A provocative new study shows that a substantial number of people who take up an exercise regimen wind up heavier afterward than they were at the start, with the weight gain due mostly to extra fat, not muscle.

運(yùn)動對健康有數(shù)不清的益處，但減肥可能并非其中之一。一項富有挑戰(zhàn)意味的新研究表明，很多人在開始執(zhí)行體育鍛煉計劃后體重反而有所增加，更糟糕的是，增加的這部分大多是多余的脂肪而不是肌肉。

But the study also finds, for the first time, that one simple strategy may improve people’s odds of actually dropping pounds with exercise.

但也正是這同一項研究首次發(fā)現(xiàn)了一種可以切實增加人們運(yùn)動減肥幾率的簡單策略。

As we all know, the fundamentals of weight loss should be simple. Burn more calories on any given day than you consume and, over time, you will lose weight. Theoretically, we can achieve that desirable condition by reducing the number of calories that we take in through dieting or by increasing the number of calories that we incinerate through exercise.

我們都知道，減肥的基本原理非常簡單。只要你每天消耗的熱量多于攝入量，隨著時間的推移，你就會越來越瘦。從理論上說，通過節(jié)食減少熱量攝入或通過運(yùn)動增加熱量消耗都能達(dá)到上述理想狀況。

But in reality, most people do not achieve or sustain weight loss, no matter what method they try.

但在現(xiàn)實中，大多數(shù)人試遍了所有方法，還是沒能達(dá)到或維持所希望的減肥效果。

Exercise is particularly problematic in this regard. A recent review of studies related to exercise and weight control found that in most of the studies, people lost barely a third as many pounds as would have been expected, given how many calories they were burning during workouts. Many studies also report enormous variations in how people’s waistlines respond to the same exercise program, with some people dropping pounds and others gaining fat.

在這方面，運(yùn)動的問題尤其大。近期的一項關(guān)于運(yùn)動和體重控制研究的綜述發(fā)現(xiàn)，在大多數(shù)的研究中，人們在運(yùn)動后的體重減輕量，只有按照鍛煉消耗的卡路里數(shù)換算出來的預(yù)期減重量的三分之一。許多研究還報告，即使執(zhí)行相同的鍛煉計劃，不同的人的腰圍變化之間也存在巨大差異，一部分人的體重減輕了，另一部分人反倒更胖了。

Scientists have had little understanding, however, of why exercise helps some people but not others to shed pounds or whether there might be early indications of how people will respond to an exercise routine.

但是，對于為什么運(yùn)動能夠幫助某些人甩掉贅肉卻對另一些人毫無用處，科學(xué)家們?nèi)匀粵]什么頭緒，此外，他們也不清楚是否有什么早期指征可以預(yù)測，有規(guī)律的鍛煉對具體的某個人的效果如何。

So for the new study, which was published last month in The Journal of Strength and Conditioning Research, scientists at Arizona State University in Phoenix recruited 81 healthy but sedentary adult women. All of the women were overweight, based on their body mass index, but some were significantly heavier than others. None had exercised regularly in the past year.

上個月，《力量與訓(xùn)練研究雜志》(The Journal of Strength and Conditioning Research)上發(fā)表了一項新研究。在這項研究中，位于菲尼克斯的亞利桑那州立大學(xué)(Arizona State University)的科學(xué)家們招募了81名習(xí)慣久坐不動的健康成年女性。根據(jù)身體質(zhì)量指數(shù)(B.M.I.)來判斷，她們?nèi)汲?，但其中一部分人超重更為顯著。在過去一年里，她們均未進(jìn)行過有規(guī)律的鍛煉。

The women were told that they would be joining a fitness study and would exercise in order to improve their aerobic endurance. The scientists asked the women not to change their eating habits in any way.

科學(xué)家們告訴這些受試女性，她們將參加一項以增強(qiáng)有氧耐力為目標(biāo)的健身研究，并要求她們不要對原來的飲食習(xí)慣作出任何改變。

Each of the volunteers visited the physiology lab at the start of the study and the scientists determined their weight, B.M.I., percentage of body fat, current endurance level, and others measures of health and fitness.

在研究開始時，每名志愿者都來到生理實驗室，接受了體重、B.M.I.、體脂百分比、當(dāng)前耐力水平等多種健康和健身指標(biāo)的測定。

Then each woman began a supervised exercise program designed to be vigorous but manageable by most people, said Glenn Gaesser, a professor of nutrition and health promotion at Arizona State and senior author of the study. The women walked on treadmills at the laboratory three times per week for 30 minutes at a pace that represented about 80 percent of their maximum endurance.

其后，她們開始在監(jiān)督下執(zhí)行鍛煉計劃，而且，據(jù)該研究的資深作者、亞利桑那州立大學(xué)的營養(yǎng)和健康促進(jìn)學(xué)教授格倫·蓋瑟(Glenn Gaesser)稱，該計劃設(shè)計的運(yùn)動強(qiáng)度很大，但還在大多數(shù)人可以接受的范圍內(nèi)。受試女性每周要在實驗室的跑步機(jī)上完成三次走步鍛煉，每次30分鐘，且節(jié)奏須保持在她們最大耐力80%的水平。

They continued the program for 12 weeks, with the scientists repeating the original fitness and other tests every month during that time.

整個鍛煉計劃持續(xù)了12周，在此期間，科學(xué)家們每月都對受試者們進(jìn)行一次與開始時一樣的健身指標(biāo)復(fù)查。

At the end of 12 weeks, the women were all significantly more aerobically fit than they had been at the start. But many were fatter. Almost 70 percent of the women had added at least some fat mass during the program, and several had gained as much as 10 pounds, most of which was from fat, not added muscle.

在第12周結(jié)束時，這些女性的有氧能力均比開始時顯著改善，但其中有不少人更胖了。在整個研究過程中，有近70%的女性體脂肪量增加，有幾個人體重增量達(dá)4.5千克，且其中大部分是脂肪而非肌肉的增加。

A few of the women, though, had lost that much fat or more, and quite a few had remained at the same weight as at the start of the regimen.

不過，仍有少數(shù)女性減掉了等量甚至更多的脂肪，還有相當(dāng)一部分女性的體重與研究開始時持平。

At this point, the researchers returned to the data from the first day of the study, to determine whether any obvious differences existed between the women who subsequently gained or lost weight. “Some past studies of dieting had indicated that women who weigh more at the beginning” of a weight-loss program “tend to lose more weight during the program,” Dr. Gaesser said.

這時，研究人員回過頭來審視研究第一天時獲得的數(shù)據(jù)，想要確定后來體重增加或減少的女性之間是否存在任何明顯的差異。蓋瑟博士說：“既往進(jìn)行的一些有關(guān)節(jié)食的研究表明”，在減肥計劃“開始時體重較重的女性更容易在鍛煉期間減肥”。

But the researchers found no correlation in this case between a woman’s weight at the start and end of the study. In fact, the scientists found no connection between any of the original parameters of health and fitness and the women’s responses to the exercise program.

但在該研究中，研究人員們發(fā)現(xiàn)受試女性研究開始時與結(jié)束時的體重間并沒有這種相關(guān)性。事實上，科學(xué)家們發(fā)現(xiàn)，這些女性在研究開始時的任何一項健康和健身參數(shù)與鍛煉計劃對她們的效果都沒有關(guān)聯(lián)。

But looking deeper into their data, they discovered one interesting indicator: Those women who were losing weight after four weeks of exercise tended to continue to lose weight, while the others did not.

但隨著更加深入地研究數(shù)據(jù)，他們發(fā)現(xiàn)了一個有趣的指征：經(jīng)過四周的鍛煉體重有所減輕的女性在后續(xù)的鍛煉中往往更容易繼續(xù)減肥，而在其他人身上則并非如此。

“What that means in practical terms is that someone who wants to lose weight with exercise” should step on the bathroom scale after a month, Dr. Gaesser said. If at that point your weight remains stubbornly unchanged or has increased, “look closely at your diet and other activities,” he said.

“其實際指導(dǎo)意義就是，如果你想要依靠運(yùn)動減肥，”就應(yīng)該在鍛煉一個月后去浴室里稱一稱體重，”蓋瑟博士說。要是此時你的體重還是不見減輕或者反而更重了，“你就得好好注意下你的飲食和其他活動了。”

While this study didn’t track the women’s eating and movement habits away from the lab, it is likely that those who gained weight began eating more and moving less when they weren’t on the treadmills, “probably without meaning to,” Dr. Gaesser said.

這項研究并沒有對受試者們的飲食和實驗室之外的運(yùn)動習(xí)慣進(jìn)行追蹤，但蓋瑟博士認(rèn)為，那些在鍛煉后體重增加的女性很可能是食量也隨之增加了，而且在跑步機(jī)鍛煉以外的時間里，她們的運(yùn)動量更少了，“雖然這應(yīng)該也不是存心的。”

Of course, the study was fairly short-term. It also did not involve men, although some past studies indicate that men, like women, frequently add fat mass after starting to exercise.

當(dāng)然，這項研究的時間相當(dāng)短，而且也沒有涉及到男性，不過此前有一些研究表明，男性和女性一樣經(jīng)常出現(xiàn)在運(yùn)動后體脂肪量反而增加的情況。