Losing weight is easier when there is money on the line, U.S. researchers said.
美国研究人员认为，当减肥与钱联系在一起时，减肥会变得更加容易。
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They said weight-loss programs that reward people with money--and remind them of the cash they stand to lose if they fail--provided a powerful incentive to lose weight compared with more conventional approaches.
他们说，与更传统的方法相比，奖励人们金钱的减肥方案——并提醒他们如果失败将可能失去奖金——为减肥提供了强大的刺激。
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Dr. Kevin Volpp of the University of Pennsylvania School of Medicine was looking for an effective way to treat obesity, a growing problem that carries serious health risks.
肥胖问题日趋严重，并伴随着很大的健康风险。美国宾夕法尼亚大学医学院的凯文沃尔普博士正致力于寻找一种行之有效的肥胖治疗方法。
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He said many weight-loss programs fail because people are being asked to make sacrifices now for rewards in the future.
他认为，很多减肥方案失败的原因在于减肥者被要求为了将来的回报而在当下做出牺牲。
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"We wanted to create a reward system which gave them rewards in the present," said Volpp, whose study appears in the Journal of the American Medical Association.
沃尔普说：“我们想建立一套现在就能给予他们回报的奖励机制。”他的研究成果已刊载在《美国医学会杂志》上。
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Volpp and colleagues studied two kinds of incentive programs for weight loss. One was a lottery-based design in which participants played a lottery and were allowed to collect their winnings if they met their weight-loss target.
沃尔普和同事一起研究了两套减肥激励方案。一种是投注法：参加者进行投注，如果达到减肥目标，就可获取奖金。


The lotteries were running daily, and people were told what their winnings would have been if they had met their weight-loss target.
投注每天进行，未达到目标的人会被告知假如他们达到了目标，原本可以获得多少钱。
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The other was a deposit contract, in which participants invested a small amount of their own money--between 1 cent and $3 per day--which they would lose at the end of the month if they failed to reach their goals. People in this group also got a bonus if they met their goal.
另一种是储蓄契约法：参加者自己投入一小笔钱——每天投入1美分到3美元——如果月底未能达到预定目标，他们就会失去这笔钱。但如果达到目标，该组成员（不仅可以拿回自己的钱）还可以得到额外的奖金。
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The researchers assigned 57 obese people to one of these two groups or a control group, in which people were simply weighed at the end of each month. All were aiming to lose 7.26 kg by the end of four months.
研究人员将57名肥胖者分进了两个激励组中的一组或者另一个控制组，每个月底这些人都要称体重。所有人的目标都是到第4个月末减去7.26公斤。
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People in the incentive groups lost far more weight than those who got no pay for their efforts, with about half of the participants in each group meeting their weight loss goals.
激励组的成员比那些努力减肥但无金钱回报的人减掉了更多的体重，而每组中都有约一半的参与者达到了其减肥目标。
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Volpp said the incentives were highly effective at producing short-term weight loss, but when the money stopped flowing, the weight began to creep back on.
沃尔普说，这种激励方式对短期的体重减少特别有效，但是一旦停止金钱激励，体重又开始反弹。
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"We need to establish whether they can be effective in sustaining weight loss as well," he said.
他说：“我们需要确定这些方法是否对维持减肥效果同样有效。”