七个最广为流传的营养谬论
七个最广为流传的营养谬论
There's a lot of misinformation out there, but dietitian Julie Upton, MS, RD, of Appetite For Health, is here to shed light on seven nutritional myths that could mess with your weight-loss efforts and your health.
网上充斥着许多虚假信息，而《爱好健康》一书的作者，营养专家Julie Upton女士在此揭秘七个可能会影响你的减肥大业甚至是健康的营养谬论。
The Internet is like the Wild West when it comes to nutrition information: anything goes. Websites are rife with less-than-accurate nutrition facts, which only fuels food myths and adds to consumers' confusion about which picks are the healthiest. At best, you can hope there's a kernel of truth in what you're reading, but more often than not, there's no scientific basis for these myths. Below are seven of the most popular nutrition myths and the real deal on each.
当涉及与营养有关的信息时，互联网就像是“狂野的西部”，各种信息纷至沓来。网上盛传各种不太准确的营养知识，这些知识只是让这些食物变得神乎其神，而使消费者更加困惑哪些选择才是最健康的。在最好的情况下，你希望自己所阅读信息的核心是正确的，但这些荒诞的说法往往没有科学依据。下面是七种最流行的营养谬论，以及事实真相。
Myth 1: You need to detox your body with a juice cleanse.
谬论1：你需要用排毒果蔬汁为身体排毒。
Fact: From celebrities to personal trainers, there's no shortage of so-called experts advocating fasts or juice cleanses to detox. If you Google "detox," you'll get nearly 64 million results for diet programs and treatments that are supposed to help "flush out your system," "remove toxic substances from the body," "give your GI tract a rest," or "speed up your metabolism" and "enhance your overall health." But despite all the hype and popularity, there's little proof that fasting or following a deprivation diet for several days actually delivers on any of the above promises.
事实：从名人到私人健身教练，倡导禁食或果蔬汁排毒的所谓专业人士不乏其人。如果你用谷歌搜索“排毒”，将得到近6400万条关于节食计划和治疗方法的结果，宣称能够帮助“冲洗身体系统”，“清除体内有毒物质”，“让你的胃肠道得到休息”或者“加速新陈代谢”以及“提高整体健康状况。”但是，尽管大肆宣传，风靡一时，却毫无证据表明禁食或剥夺饮食一段时间真的能够达到上面所说的任何效果。
While an occasional short fast or a day of following a "juice diet" won't cause harm for most healthy people, it will likely leave you feeling cranky and hungry. If you really want to be and feel your best, eat a healthy diet that includes plenty of fruits and vegetables, get adequate sleep, and don't drink more than one alcoholic beverage per day.
偶尔短期禁食或者一天之内参照“果汁饮食”对大部分健康的人不会造成危害，却有可能让你感到暴躁和饥饿。如果你真的想达到最佳状态，可以食用含有充足的水果和蔬菜的健康饮食，保证充足的睡眠，每天最多饮用一份含酒精的饮料。
Myth 2: Diet sodas make you gain weight.
谬论2：无糖汽水让你体重增加。
Fact: While you may have read that diet beverages make you gain weight, a recent clinical trial found just the opposite. In the 12-week study, published in the journal Obesity, dieters who drank diet beverages lost 13 pounds on average — 44 percent more than subjects drinking water only, who lost an average of nine pounds. What's more, the diet-soda drinkers reported feeling more satisfied. This study adds to a substantial body of research demonstrating that low-calorie sweeteners and the diet beverages that contain them do not hinder but can in fact help with weight loss. Two peer-reviewed studies published in the American Journal of Clinical Nutrition by researchers from the University of North Carolina in 2012 and 2013 randomly assigned subjects to drink either water or diet beverages (without making any other changes to their diet). After six months, the diet-beverage group had a greater likelihood of reaching a meaningful amount of weight loss — five percent of one's body weight — compared to the control group. These studies reinforce that if you're trying to lose weight, diet beverages may help you peel off pounds, as they can help you achieve and maintain a lower-calorie eating plan.
事实：或许你曾经看到有文章说无糖汽水会让你体重增加，但最近一项临床试验却发现了截然相反的结果。该试验发表在《肥胖》期刊上，在为期12周的研究中，饮用节食饮料的节食者平均减轻了13磅——比每天只喝水的试验对象多44%，后者平均减肥9磅。此外，喝无糖汽水的人报告感觉更满足。该结果为此前一项大型研究提供了支持。此前的研究表明：低热量甜味剂和含有低热量甜味剂的无糖饮料不会妨碍减肥，反而对减肥有所帮助。两项同行评审的研究发表在美国《临床营养学》期刊上，由来自北卡罗来纳大学的研究人员进行。他们在2012年和2013年随机选择研究对象，让他们饮用水或无糖饮料（而他们的其它饮食不作任何改变）。六个月后，与控制组相比，饮用无糖饮料的一组研究对象达到有意义的减肥目标的可能性更大——减轻了体重的5%。这些研究更说服人们相信，如果你想要减肥，无糖饮料或许可以帮你减轻体重，因为它们可以让你达到并维持低热量饮食计划。
Myth 3: Canola oil is made from rapeseed plants, which are toxic.
谬论3：芥花油是用油菜植株制成的，是有毒的。
Fact: Canola oil comes from the crushed seeds of canola plants — not rapeseed plants, which are, in fact, harmful. Rapeseed oil contains high levels of erucic acid, which is linked to heart disease and therefore is not allowed to be sold in the US. While the two plants are cousins, they're distinctly different in their composition. In the 1960s, farmers used breeding methods to help eliminate the erucic acid from canola plants, and canola oil is now regulated to contain negligible amounts of the compound, ensuring that canola oil is 100 percent safe. In fact, it also happens to be one of the healthiest oils (behind olive oil) because it has less saturated fat and more heart-protective omega-3s than other vegetable oils. Canola oil is just seven percent saturated fat compared to olive oil, which is 15 percent saturated fat.
事实：芥花油是用压碎的加拿大油菜籽制成的——而不是有害的油菜。菜籽油中含有大量的芥酸，会造成心脏病，因此在美国不允许售卖。尽管这两种植物是近亲，它们的成分却存在显著差异。20世纪60年代，农民们使用育种方法来消除芥花植株中的芥酸，现在其中含有的芥酸几乎可以忽略不计，从而保证了芥花油是100%安全的。实际上，这也是最健康的油之一（仅次于橄榄油），因为与其它植物油相比，它含有更少的饱和脂肪和更多保护心脏的ω-3脂肪酸。与橄榄油相比，芥花油仅含有7%的饱和脂肪，而橄榄油含有15%的饱和脂肪。
Myth 4: Sea salt has less sodium than table salt and is mineral-rich.
谬论4：海盐比食盐含钠量更少，且矿物质丰富。
Fact: Run-of-the-mill Morton table salt and gourmet Himalayan sea salt contain essentially the same amount of sodium per teaspoon — 2,300 milligrams. As for minerals, neither contains enough of any mineral to make it a clear winner over the other. For instance, a teaspoon of table salt has just 1 mg calcium compared to 12 mg in sea salt. Since 12 mg is just one percent of your daily needs, it's not a very healthy way to get calcium into your diet.
事实：从本质上来说，每茶匙普通莫顿食盐和美味的喜马拉雅海盐的钠含量是一样的，都是2300毫克。至于矿物质，两者中含有的任何一种矿物质都没有明显的优势。例如，一茶匙食盐仅含有1毫克的钙，而海盐中含有12毫克钙。由于12毫克的钙仅仅是每天需求量的1%，食用海盐并不是向饮食中添加钙的健康方法。
Most people believe that sea salt tastes better and, in some cases, you may be able to use less of it (and therefore reduce your sodium intake), but it is by no means a lower-sodium and more mineral-rich option. Keep in mind, sea salt lacks iodine — and not getting enough of this compound can lead to goiter, intellectual impairments, growth retardation, and much more. In fact, iodine deficiency is a serious health threat, especially among pregnant women, according to Boston University researchers, so don't use sea salt exclusively in your diet.
大部分人相信海盐味道更好，某些情况下，使用量可以更少（因此就可以减少钠的摄入量），然而这绝对不是减少钠，增加矿物质的选择。要记住，海盐中缺少碘，没有摄入足够的碘会导致甲状腺肿大，智力缺陷，生长发育迟缓等等。实际上，据波士顿大学研究人员所说，缺碘是一种严重的健康威胁，尤其是对孕妇来说。所以，不要在饮食中特意使用海盐。
Myth 5: Some foods, like celery, have negative calories.
谬论5：一些食物，比如芹菜，含有负卡路里。
Fact: When something sounds too good to be true, well, it probably is. Take "negative-calorie foods" as an example. The notion is that digesting certain foods burns more calories than those foods provide. The faulty logic of this urban legend is based on the scientifically proven thermic effect of food (TEF), which simply means the amount of energy the body uses to digest a food. The thinking goes, if you were to eat a very low-calorie food — common examples include celery, apples, and limes — then you'd actually create a calorie deficit. In other words, these foods would end up costing less-than-zero calories.
事实：当某件事听上去太好以致于不现实的时候，可能真的不现实。以“负卡路里食物”为例，这个概念是指消化某种食物燃烧的热量超过食物提供的热量。这个都市传奇的错误逻辑是基于经科学证实的食物产热效应（TEF），意思是指身体用来消化食物的能量。由此推测，如果你食用热量非常低的食物——最常见的例子包括芹菜，苹果和酸橙——这样就会产生热量赤字。换句话说，这些食物产生的热量是负值。
Sadly, there are no negative-calorie foods. The TEF generally ranges from 10 percent to 20 percent of the calories in a food. So let's say a celery stalk has seven calories. Even if you assume a 20 percent TEF, that means you're still left with about five and a half calories.
悲哀的是，根本没有负卡路里食物。TEF大概介于食物热量的10%至20%之间。比方说一根芹菜含有7卡路里的热量。即使TEF为20%，这意味着仍然剩下5.5卡路里的热量。
Myth 6: It takes 21 days to break a bad habit (or form a new one).
谬论6：打破坏习惯（或者养成新习惯）需要21天。
Fact: Popular self-help gurus and many diet plans claim that it will take 21 days to form a new healthy habit — or break a bad one. The truth is, there is no magical time frame for breaking bad habits. One study that evaluated behavior change found that creating a new habit, like eating a piece of fruit daily, took an average of 66 days. However, there were wide variations — anywhere from 18 days to 254 days. The authors found the adaptation time was a function of how hard the new behavior is as well as the individual. If you're trying something new, like daily exercise, give yourself time to make it a routine. It may not happen overnight — or even in 21 days!
事实：受欢迎的自助专家和许多节食计划都宣称，养成新的健康习惯——或者打破坏习惯需要21天的时间。实际情况是，破除坏习惯没有神奇的时间框架。评估行为变化的一项研究发现，养成新的习惯，比如每天吃一份水果，平均需要66天的时间。然而，每人的情况各有不同——介于18天至254天之间。作者们发现，适应时间是新习惯的困难程度和个人毅力的函数。如果你正在尝试某件新的事情，比如每天锻炼身体，给自己时间让它成为日常习惯。这不会在一夜之间发生——甚至21天也是不可能的。
Myth 7: Muscle can turn to fat ( . . . and vice versa).
谬论7：肌肉可以和脂肪相互转化。
Fact: You'll often hear someone at the gym say something like, "Since my injury, my muscles have turned to mush." But this isn't the case because muscle and fat tissues are entirely different, and therefore they can never transform from one to the other. It's the equivalent of saying you can turn water into wine or lead into gold.
事实：你可能在健身房听到有人说，“由于受了伤，我的肌肉都变成脂肪了。”但事实并非如此，因为肌肉和脂肪组织是完全不同的，因此永远不可能相互转化。就好像说你可以把水变成葡萄酒或者把铅变成金子一样荒谬。
What really happens when you stop exercising is that your muscle mass declines. And how you gain fat tissue is when you eat more calories than you burn off, which is much easier to do when you're not exercising. And likewise, when you up your exercise routine, you'll add lean tissue and might start burning excess body fat, but your fat didn't turn into muscle.
当你停止锻炼的时候，你的肌肉质量会下降。而当你摄入的热量多于燃烧的热量时，你的脂肪组织就会增加，这比不锻炼容易得多。同样地，当你加强锻炼的时候，瘦肉组织将开始增加，过量的身体脂肪也可能开始燃烧，但是脂肪不会变成肌肉。
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