In The Origin Diet, dietitian Elizabeth Somer asserts that certain cravings were central to human survival and evolution. "Fat and sugar were scarce hundreds of thousands of years ago," she writes."Fat was a precious source of calories (supplying more than twice the calories per gram of either protein or starch), and our ancestors had no need to develop an appetite shutoff valve for fat. Instead, when they found fatty food, they ate all they could get and developed an unlimited capacity to store extra calories."

     在《源頭節(jié)食》一書中，營養(yǎng)學家Elizabeth Somer斷言：某些吃的渴望在人類生存和進化中曾經起到了重要作用。"幾十萬年以前，脂肪和糖是很缺乏的，"她這樣寫道。 "而脂肪是熱量重要來源（每克脂肪提供的卡路里是蛋白質或淀粉的兩倍多），因此我們的祖先在當時并不需要控制脂肪的攝入量。相反，當他們發(fā)現富含脂肪的食物時，他們有多少吃多少，并練就了一種無限儲存過多熱量的能力。"
 
    The quest for fat and sugar, Somer believes, is now hardwired into our brains, governed by dozens of chemicals including endorphins. Serotonin, for example, is the "feel good" chemical. When levels are low, we seem to crave sweets and carbs, which raise serotonin and improve mood. This may help explain why many women crave chocolate near their periods.

    Somer相信這種對脂肪和糖的渴望現已在我們的大腦中固定下來，大腦受到包括內啡素的十幾種化學物質的控制。譬如血清素是產生"好的感覺"的化學物質。當它的含量降低時，我們似乎就會渴望糖和碳水化合物，因為它們能提高血清素含量并改善情緒。這一點也許有助于解釋為什么很多女性在經期前后會想吃巧克力。
 
    What about the cravings that many pregnant women experience? Growing research suggests that odd food yearnings - and food aversions - may protect the fetus. Some pregnant women lose the desire to drink coffee or wine and turn green at the sight of fish, meat, eggs or vegetables. Instead, they crave sweets, fruits (especially citrus) and dairy products.

    如何解釋很多孕婦對某些食物的偏好呢？越來越多的研究表明對一些奇怪食物的偏好--和厭惡--可能是出于保護胎兒的緣故。有些孕婦不再愛喝咖啡或紅酒，并且一看到魚、肉、蛋或蔬菜就倒胃口。但是，她們卻變得愛吃甜食、水果（尤其柑橘）和奶制品。
 
    One explanation: These foods are least likely to carry harmful organisms or natural toxins. "It may be your body is telling you to keep your fetus away from anything that might be toxic," says Frances Largeman, managing editor of FoodFit.com, a website promoting healthy eating habits.

    有一種解釋：這些食物中含有害微生物或天然毒素的可能性最小。"可能是你的身體在教你避免使胎兒接觸可能有毒的食物，"致力于宣傳健康飲食習慣的FoodFit.com網站主編Frances Largeman說。
 
    Largeman acknowledges that the theory doesn't account for why some pregnant women hunger for pickles and others for apple strudel. Cravings are difficult to explain scientifically, she says, "because people don't eat nutrients; they eat food." And everybody's preferences differ.

    Largeman承認該理論無法解釋為什么有些孕婦愛吃泡菜，有些愛吃蘋果餡餅。吃的渴望很難從科學上解釋，她說。"因為人們不是吃營養(yǎng)，而是吃食物。"而各人偏好又是千差萬別。
 
    One explanation: These foods are least likely to carry harmful organisms or natural toxins. "It may be your body is telling you to keep your fetus away from anything that might be toxic," says Frances Largeman, managing editor of FoodFit.com, a website promoting healthy eating habits.

    有一種解釋：這些食物中含有害微生物或天然毒素的可能性最小。"可能是你的身體在教你避免使胎兒接觸可能有毒的食物，"致力于宣傳健康飲食習慣的FoodFit.com網站主編Frances Largeman說。
 
    Largeman acknowledges that the theory doesn't account for why some pregnant women hunger for pickles and others for apple strudel. Cravings are difficult to explain scientifically, she says, "because people don't eat nutrients; they eat food."And everybody's preferences differ.

    Largeman承認該理論無法解釋為什么有些孕婦愛吃泡菜，有些愛吃蘋果餡餅。吃的渴望很難從科學上解釋，她說。"因為人們不是吃營養(yǎng)，而是吃食物。"而各人偏好又是千差萬別。
 
    Some experts think cravings are as much a reflection of our social and psychological makeup as they are of our physiological impulses. "Food adds solace to our lives," says Jeff Hampl, a spokesman for the American Dietetic Association. "Often, cravings are tied to a childhood experience and good feelings associated with it. There's a subconscious desire to replace those emotions."

    有些專家認為吃的渴望除了能反映我們生理沖動以外，還能反映我們社會和心理構成。"食物給我們生活帶來慰藉，"美國飲食協(xié)會發(fā)言人Jeff Hampl說。"吃的渴望常常與童年某段經歷以及與此相關的美好情感有聯系。人的潛意識渴望恢復這種情感。"
 
    This would explain my predilection for rapini, since my mother serves it every Thanksgiving. Yet regardless of the reason, Largeman - who craves salmon sometimes - thinks you should satisfy a craving when it strikes. "A craving usually just gets worse," She says,"and it could lead to binging."

    這也許能解釋為何我會對迷迭香情有獨衷，這是因為我媽媽在每個感恩節(jié)都會做這道菜。不過，不論原因如何，有時會渴望鮭肉的Largeman認為，當這種渴望出現時，你都應該去滿足它。"渴望通常只會愈演愈烈，"她說，"它會導致暴飲暴食。"
 
    But most of us long for foods that aren't as nutritious as salmon. What should we do?

    但是大多數人所渴望的食物不及鮭肉營養(yǎng)豐富。我們應該怎么做呢？
 
    First, make sure you're experiencing a true craving - not just plain old hunger or thirst. "Sometimes people don't realize they're physically hungry," says O'Neil."If it's actually hunger, eating something reasonable such as a piece of fruit rather than a chocolate bar might do the trick."

    首先，必須確定你正經歷一種真正的渴望--而不是普通饑渴。"有時，人們意識不到自己身體正處于饑餓狀態(tài)，"O'Neil說。"如果真是饑餓的話，那么選擇合理的食物，譬如一片水果而不是一塊巧克力，就可以奏效。"
 
    Another option, he says, is to"leave the scene of the craving. Change your setting and engage in other things that don't involve food."

    另一個辦法，他說，是"離開想吃東西的場所。改變一下環(huán)境，做一些與吃無關的事情。"
 
    Finally, if your craving just won't be rebuffed, indulge it - judiciously."If you have a salty craving," says Largeman, "it's better to buy a single-serving bag of salt-and-vinegar chips than to buy a large bag and keep it around the house." Or try a less potent alternative - say, low-fat chocolate milk or a frozen fudge pop rather than a slab of fudge.

    最后，如果你實在無法打消吃的渴望，那么就放縱自己吧--不過要適度。"如果你愛吃咸食，"Largeman說，"那么買一袋一人吃的咸醋味薯片要比買一大袋放在家里好。"或者還可以選擇一個低熱量的品種--譬如低脂巧克力牛奶或一瓶冰凍的乳脂軟糖汽水而不是一大塊乳脂軟糖。
 
    For years, Catherine Monk would ignore her sweet tooth, then splurge on half a pint of ice cream. Now wiser, she settles for a few table-spoons every night."That does it for me," she says. 

    幾年來，Catherine Monk一直克制自己對甜食的渴望，壓制不了時，就無節(jié)制地吃半品脫冰淇淋。現在，她變聰明多了，每晚只允許自己吃上幾勺。"這對我很有效，"她說。