It's not gluttony. It's genetics. Why our moralizing misses the point.

    Despite receiving a MacArthur genius award for her work in Alabama "forging an inspiring model of compassionate and effective medical care in one of the most underserved regions of the United States," Regina Benjamin's qualifications to be surgeon general have been questioned. Why? She is overweight. "It tends to undermine her credibility," Dr. Marcia Angell, former editor of The New England Journal of Medicine, said in an interview with ABC News. "I do think at a time when a lot of public-health concern is about the national epidemic of obesity, having a surgeon general who is noticeably overweight raises questions in people's minds."

    It is not enough, it seems, that the obese must suffer the medical consequences of their weight, consequences that include diabetes, heart disease, and cancer, and that cause nearly 300,000 deaths in the United States each year. They must also suffer the opprobrium heaped on them by people like Angell or Rep. James Sensenbrenner （R-WI）, who advised the obese to "Look in the mirror because you are the one to blame." In our society, perhaps no group is more stigmatized than the obese.

    The abuse is nothing new, of course. Four hundred years ago, Shakespeare had Prince Hal hurl a barrage of insults at Falstaff, calling him "fat-witted," "horseback-breaker," and a "huge hill of flesh." But Shakespeare had an excuse. In his time essentially nothing was known about the real reasons that people are fat. Today we have no such excuse. Modern medical science has gone a long way toward explaining the causes of obesity, and the bottom line is clear: obesity is not a personal choice. The obese are so primarily as a result of their genes.

    Genetic studies have shown that the particular set of weight-regulating genes that a person has is by far the most important factor in determining how much that person will weigh. The heritability of obesity-a measure of how much obesity is due to genes versus other factors-is about the same as the heritability of height. It's even greater than that for many conditions that people accept as having a genetic basis, including heart disease, breast cancer, and schizophrenia. As nutrition has improved over the past 200 years, Americans have gotten much taller on average, but it is still the genes that determine who is tall or short today. The same is true for weight. Although our high-calorie, sedentary lifestyle contributes to the approximately 10-pound average weight gain of Americans compared to the recent past, some people are more severely affected by this lifestyle than others. That's because they have inherited genes that increase their predisposition for accumulating body fat. Our modern lifestyle is thus a necessary, but not a sufficient, condition for the high prevalence of obesity in our population.

    Over the past decade, scientists have identified many of the genes that regulate body weight and have proved that in some instances, different variants of these genes can lead a person to be fat or thin. These genes underlie a weight-regulating system that is remarkably precise. The average person takes in a million or more calories per year, maintaining within a narrow range over the course of decades. This implies that the body balances calorie consumption with calorie expenditure, and does with a precision greater than 99.5 percent. Even the most vigilant calorie counter couldn't compete, if for no other reason than that the calorie counts on food labels are often off by 10 percent or more.

    The genes that control food intake and metabolism act to keep weight in a stable range by creating a biological force that resists weight change in either direction. When weight is gained, hunger is reduced. When weight is lost, the unconscious drive to eat is stimulated and acts to return weight to the starting point. Moreover, the greater the amount of weight that is lost, the greater the sense of hunger that develops. Thus, when the obese lose large amounts of weight by conscious effort, their bodies fight back even more strongly by increasing hunger and reducing energy expenditure. If you think it is hard to lose 10 to 20 pounds （and it is）, try to imagine what it would feel like to lose many tens or even hundreds of pounds.

    肥胖不是因为贪婪的暴食，而是因为个体基因决定的。为什么我们在评判胖人时忘记这一点呢？

    尽管Regina Benjamin因在阿拉巴马州的工作使得"在美国最缺乏医疗的地区铸造了令人欣慰鼓舞的爱心高效医疗体系"被授予麦克阿瑟天才奖（MacArthur genius award）,但她成为卫生局局长的资格遭到了质疑。这是为什么呢？她超重了。"就这个理由似乎就破坏了她的信誉",作为The New England Journal of Medicine期刊的前任编辑Marcia Angell博士说，"我的确认为，当对公众健康的担忧集中于在美国日益扩展的肥胖问题时，人们就会对明显超重的卫生局局长进行质疑。"

    肥胖者必须遭受着超重带来的疾病如糖尿病，心脏病，癌症等，由此肥胖每年导致近300,000美国人死亡，似乎这还不算，他们还得承受着很多人堆积在他们身上的冷嘲热讽，羞辱责骂，像是Angell or Rep. James Sensenbrenner （R-WI）曾经就建议肥胖者"照照镜子就知道你们该骂".在我们的社会，估计没有任何群体会像胖人们一样被歧视虐待了。

    当然，肥胖不是个新问题。早在400年前，莎士比亚笔下的Hal王子就被刻画地不断地讽刺Falstaff,并称呼他为"愚笨的胖子","害苦坐骑的胖子"和"山堆的肥肉".但是莎士比亚是有理由这样做的，因为在他那个时代世人完全不晓得导致肥胖的真正原因。而今我们不应该有任何理由。当代医学科技已经在探索肥胖原因方面发展很多了，最重要的一点很清楚：肥胖不是个人选择的，而是基因的作用。

    基因学研究显示：个体带有的体重调节基因是决定其体重的最重要因素。肥胖的可遗传性---一种测量基因和其他因素导致肥胖多少的方法--就和身高的可遗传性一样起作用，它对导致肥胖的作用甚至比已经接受的像心脏病和乳癌的基因的遗传作用还要大的多。随着过去200年中营养摄入的不断提高，美国人的平均身高已经提高了很多，但是还是会有基因的作用决定着人们不同的高矮。体重其实也是一样。尽管我们由于高卡路里摄入，久坐的生活方式导致了近年来美国人的平均体重比过去将近涨了10磅，但是总是有些人比其他人更多的受到这种生活方式的影响而变胖。这是因为他们遗传了让他们倾向于累积脂肪的基因。我们的现代不良生活方式是个必然因素导致肥胖，但并不是致使我们整体人口数量中肥胖人口快速蔓延的全部原因。

    在过去的十年里，科学家识别了体重调节基因并且证明了不同倾向的基因可以决定一个人的胖瘦。这些基因含有一个精确的体重调节系统。一般平均下来一个人一年要摄入一百万甚至更多的卡路里，但是在几十年里体重却一直保持在变化幅度很小的范围中。这就显示了身体自身平衡用卡路里消耗抵消了卡路里的摄入，这一抵消程度都超过了99.5%.就是最危险的很多卡路里摄入量也不能抗击住这中平衡系统，如果不是这种基因作用，那食品标签上的卡路里都得降10%甚至更多才能保持这样的体重。

    这个控制从食物中吸收的热量和新陈代谢功能以达到保持体重的基因创造出了一种可以避免体重变化的生理力量。当体重增加时，饥饿感降低。当体重减少时，食欲被无意识得激发，开始扭转局势使体重回归。而且，体重减得越多，饥饿感越强烈。所以，当肥胖患者有意识的努力减下了体重时，他们的身体就更强烈的激发出提高食欲和降低能量消耗的战斗力。所以，如果你觉查到减掉10磅甚至20磅是很困难的，那么设想一下，要减掉几十磅甚至几百磅会是什么感受！