Exercise is one of the few factors with a positive role in long-term maintenance of body weight. Unfortunately, that message has not gotten through to the average American, who would rather try switching to "light" beer and low-calorie bread than increase physical exertion. The Centers for Disease Control, for example, found that fewer than one-fourth of overweight adults who were trying to shed pounds said they were combining exercise with their diet.

　　In rejecting exercise, some people may be discouraged too much by caloric-expenditure charts; for example, one would have to briskly walk three miles just to work off the 275 calories in one delicious Danish pastry (小甜饼). Even exercise professionals concede half a point here. "Exercise by itself is a very tough way to lose weight," says York Onnen, program director of the President's Council on Physical Fitness and Sports.

　　Still, exercise's supporting role in weight reduction is vital. A study at the Boston University Medical Center of overweight police officers and other public employees confirmed that those who dieted without exercise regained almost all their old weight, while those who worked exercise into their daily routine maintained their new weight.

　　If you have been sedentary (极少活动的) and decide to start walking one mile a day, the added exercise could burn an extra 100 calories daily. In a year's time, assuming no increase in food intake, you could lose ten pounds. By increasing the distance of your walks gradually and making other dietary adjustments, you may lose even more weight.

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　　运动是少数几项在长期保持体重上扮演着积极角色的因素之一。然而不幸的是，这一理念却未能被普通美国人所了解。这些人宁愿尝试选择清淡啤酒和低热量的面包，也不愿增加体能的消耗。例如，美国疾病控制中心研究发现，在力图减肥的人群中，不到1/4的人将运动和节食结合了起来。

　　在拒绝运动的过程中，一些人或许是因为热量消耗图表而被大大的挫伤了信心。例如，一个人必须要轻快的行走3英里，仅仅来消耗由一块可口的丹麦小甜饼所产生的275卡热量。甚至就连专业的运动人士对此也不得不部分地承认。“运动本身就是一种很困难的减肥方法。”美国总统身体健康和运动委员会的项目主管，约克·昂尼说。

　　然而，运动对减肥的辅助作用仍然是至关重要的。一份由波士顿大学医学中心所做的对过胖的干警和其他的公职人员的研究证实，那些只节食而不运动的人几乎完全恢复了原有的体重，而那些将运动列入了日常工作的人则保持了新的重量。

　　如果你经常坐着缺乏运动，现在决定开始每天步行一英里，这增添的运动量每天可以额外燃烧100卡的热量。在一年之内，假如进食量不增加的话，你可以减10磅。通过逐渐增加步行的距离以及做些饮食方面的调整，你甚至可以减得更多。