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?yàn)樨澙返谋┦�，而是因�(yàn)閭�(gè)體基因決定的。為什么我們?cè)谠u(píng)判胖人時(shí)忘記這一點(diǎn)呢？

    盡管Regina Benjamin因在阿拉巴馬州的工作使得"在美國(guó)最缺乏醫(yī)療的地區(qū)鑄造了令人欣慰鼓舞的愛心高效醫(yī)療體系"被授予麥克阿瑟天才獎(jiǎng)（MacArthur genius award）,但她成為衛(wèi)生局局長(zhǎng)的資格遭到了質(zhì)疑。這是為什么呢？她超重了。"就這個(gè)理由似乎就破壞了她的信譽(yù)",作為The New England Journal of Medicine期刊的前任編輯Marcia Angell博士說，"我的確認(rèn)為，當(dāng)對(duì)公眾健康的擔(dān)憂集中于在美國(guó)日益擴(kuò)展的肥胖問題時(shí)，人們就會(huì)對(duì)明顯超重的衛(wèi)生局局長(zhǎng)進(jìn)行質(zhì)疑。"

    肥胖者必須遭受著超重帶來的疾病如糖尿病，心臟病，癌癥等，由此肥胖每年導(dǎo)致近300,000美國(guó)人死亡，似乎這還不算，他們還得承受著很多人堆積在他們身上的冷嘲熱諷，羞辱責(zé)罵，像是Angell or Rep. James Sensenbrenner （R-WI）曾經(jīng)就建議肥胖者"照照鏡子就知道你們?cè)摿R".在我們的社會(huì)，估計(jì)沒有任何群體會(huì)像胖人們一樣被歧視虐待了。

    當(dāng)然，肥胖不是個(gè)新問題。早在400年前，莎士比亞筆下的Hal王子就被刻畫地不斷地諷刺Falstaff,并稱呼他為"愚笨的胖子","害苦坐騎的胖子"和"山堆的肥肉".但是莎士比亞是有理由這樣做的，因?yàn)樵谒�那個(gè)時(shí)代世人完全不曉得導(dǎo)致肥胖的真正原因。而今我們不應(yīng)該有任何理由。當(dāng)代醫(yī)學(xué)科技已經(jīng)在探索肥胖原因方面發(fā)展很多了，最重要的一點(diǎn)很清楚：肥胖不是個(gè)人選擇的，而是基因的作用。

    基因?qū)W研究顯示：個(gè)體帶有的體重調(diào)節(jié)基因是決定其體重的最重要因素。肥胖的可遺傳性---一種測(cè)量基因和其他因素導(dǎo)致肥胖多少的方法--就和身高的可遺傳性一樣起作用，它對(duì)導(dǎo)致肥胖的作用甚至比已經(jīng)接受的像心臟病和乳癌的基因的遺傳作用還要大的多。隨著過去200年中營(yíng)養(yǎng)攝入的不斷提高，美國(guó)人的平均身高已經(jīng)提高了很多，但是還是會(huì)有基因的作用決定著人們不同的高矮。體重其實(shí)也是一樣。盡管我們由于高卡路里攝入，久坐的生活方式導(dǎo)致了近年來美國(guó)人的平均體重比過去將近漲了10磅，但是總是有些人比其他人更多的受到這種生活方式的影響而變胖。這是因?yàn)樗麄冞z傳了讓他們傾向于累積脂肪的基因。我們的現(xiàn)代不良生活方式是個(gè)必然因素導(dǎo)致肥胖，但并不是致使我們整體人口數(shù)量中肥胖人口快速蔓延的全部原因。

    在過去的十年里，科學(xué)家識(shí)別了體重調(diào)節(jié)基因并且證明了不同傾向的基因可以決定一個(gè)人的胖瘦。這些基因含有一個(gè)精確的體重調(diào)節(jié)系統(tǒng)。一般平均下來一個(gè)人一年要攝入一百萬甚至更多的卡路里，但是在幾十年里體重卻一直保持在變化幅度很小的范圍中。這就顯示了身體自身平衡用卡路里消耗抵消了卡路里的攝入，這一抵消程度都超過了99.5%.就是最危險(xiǎn)的很多卡路里攝入量也不能抗擊住這中平衡系統(tǒng)，如果不是這種基因作用，那食品標(biāo)簽上的卡路里都得降10%甚至更多才能保持這樣的體重。

    這個(gè)控制從食物中吸收的熱量和新陳代謝功能以達(dá)到保持體重的基因創(chuàng)造出了一種可以避免體重變化的生理力量。當(dāng)體重增加時(shí)，饑餓感降低。當(dāng)體重減少時(shí)，食欲被無意識(shí)得激發(fā)，開始扭轉(zhuǎn)局勢(shì)使體重回歸。而且，體重減得越多，饑餓感越強(qiáng)烈。所以，當(dāng)肥胖患者有意識(shí)的努力減下了體重時(shí)，他們的身體就更強(qiáng)烈的激發(fā)出提高食欲和降低能量消耗的戰(zhàn)斗力。所以，如果你覺查到減掉10磅甚至20磅是很困難的，那么設(shè)想一下，要減掉幾十磅甚至幾百磅會(huì)是什么感受！