麻省哈佛代谢专家：我是如何通过合理饮食，维持身体健康的？
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本文首发自微信公众号：瘦龙健康，中国肥胖问题的死磕侠，我已委托“维权骑士”（http://rightknights.com）为我的文章进行维权行动.
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本文编辑时间（10 个小时），预计阅读时间，10 分钟
今天的主讲人是Dr . Stephen Phinney，斯塔福大学硕士研究生，麻省理工大学博士，哈佛博士后，他是加利福尼亚、明尼苏达、佛蒙特等多所大学的教授，致力于饮食、运动及脂肪酸代谢，炎症等领域的研究长达35年。
他的代表作《TheNew Atkins for a New You》被纽约时报评为2010年度畅销书。今天视频的主题是基于他的另一部代表作，低碳生活的科学与艺术《The Art And Science of Low-Carbohydrate Living》。
https://v.qq.com/txp/iframe/player.html?vid=l0394m8fzsp&width=500&height=375&auto=0
因为时间关系就不做字幕，下面有视频大意，中英文的翻译，如果你可以看懂英文，建议直接看英文视频，看完这个视频你可以收获如下的知识要点：
人体适应低碳饮食的周期，适应了低碳生酮饮食后爆碳存在哪些风险？
为什么高碳水饮食容易让你饥饿，情绪不稳定，暴躁。
以居住在北极地区的因纽特人为例，证实了近乎零碳水化合物饮食，也可以保持机体的健康状态。
低碳生酮饮食应该如何吃，如何选择适合的脂肪作为机体的能量来源？
这个视频是以采访的形式进行的，所以在下文会以问(Q,Question) 和答(A,Answer)的形式进行。
问： 什么是低碳饮食，如何长期坚持低碳？
Q: What is low carb and how do you do it long term? That’s your area ofexpertise, right?
答： 是的，我一直对于机体如何适应低碳饮食(通常定义为少于50g/天)十分感兴趣，要适应这样的饮食习惯，通常需要经历几个阶段。
低碳意味着要放弃很多甜的、美味的食物，或者是一些日常习惯的食物（像国人对于大米和面条的“眷恋”），但我更感兴趣的是人体是如何适应低碳的饮食习惯的。
从我过去十几年的研究结果中，我发现我们至少需要2周（通常是4到6周）的时间才能适应低碳饮食，紧接着维持这样的饮食（毫无间断）直到机体完全适应，最终到达营养学上称之为的“酮症”状态（我个人将它命名为“酮适应”）。
一旦到达“酮适应”状态，机体的能量来源就发生了彻底的变化，表现为能够更好地利用脂肪。即使是一个瘦子，体内的脂肪也可以储备近达1万大卡的热量，而糖原的储备仅仅是一两千大卡。
“酮适应”状态可以帮助胖子更加容易地使用机体储存的多余脂肪，进而达到减肥的目的。
A: Yes, I’ve been very interested in how humans adapt to low-carbohydratediets and there are multiple phases of forms of adaptation. Of course there isa fact that you have to give up something that’s sweet or it’s delicious orfood that you eat and those are behavioral adaptations. And those do occur, butmy interest has been how the human body adapts and if I’ve made onecontribution over the last few decades of my research, it’s demonstrating thatthe full adaptation when one takes most of the carbs of the diet requires atleast two weeks and probably like four to six weeks. Then staying continuouslylow-carb without interruption for the body to fully undergo adaptation to whatI call nutritional ketosis. So the term we developed for that is what we callketo adaptation. If the people undergoes keto adaptation, the body fuel usefundamentally changes and the most obvious aspect of that is one has mucheasier access to body fat stores, basically to the large fuel tank that wecarry with us. Even a lean person can carry 10,000 calories of fat in body fatstores, but only 1000 to 2000 calories is glycogen. So by keto adapting, youactually get access to your much larger reserves of fuel. That’s mean, if oneis overweight, it makes it more feasible to lose the extra weight and get downto a lean body weight.
问：人们应该如何长期坚持低碳饮食呢？
Q: How do people stay in this long term?
答： 执行低碳的过程远比不吃碳水化合物来得更复杂，为了保持机体能够长期使用脂肪作为能量来源，我们必须维持机体处于“酮症”状态。
这个的好处在于，我们的大脑可以使用酮体作为能量来源，因而你不会因为大脑供能不足而产生烦躁、饥饿等感觉，而这些感觉通常发生在高碳水饮食的状态。
也就是说，如果一个人想要维持低碳饮食，那么他就不能让自己“放纵”，一天也不行， 如果在低碳饮食中穿插一天的高碳饮食，那么机体就需要再花2到4周的时间重新回到“酮症”状态。这就是爆碳水的代价哦
A: It’s a little more complex than just not eating carb. In order tomaintain this optimum access to body fat fuel, one needs to in essence to stayin a ketogenic state, and the benefits of nutritional ketosis are quite simplythe fact that the brain has a continuous supple of fuel. So you won’t have thefeelings of anxious or hunger due to the short of energy supply, which ishappening on a low carb on a high carb diet or even intermittent doses of carb.So one of the messages is that in order to do low carb long-term, you need tostay low-carb. You cannot have holidays, or take one day or a weekend off. Ifyou take one day off, it takes 2 to 4 weeks to readapt.
问： 如果在短期高碳饮食后，重新适应的周期会减短吗？
Q: What if you just take a short break and go back, is the adaptation quicker?
答： 目前尚无临床研究的证据证明这一点，但就我多年的临床经验来看，如果短期高碳饮食，人们通常需要一到两周的适应时间，才能使得血液中酮体的水平再次回到相对稳定的状态。
可以将我们机体对于“酮症”状态的适应，比喻成居住在一个陡峭沙丘的顶部，想要爬到顶端是件比较困难的事情，然而一到到达，就可以长期稳定地住在上面。然而一旦你滑下来，想再回到顶端，那又会是件不容易的事。
A: This excellent question hasn’t been adequately studied with objectiveresearch. But in my clinical practice, if they took a weekend off, when wemeasured ketone levels in the blood, it took at least a week or two weeks tobring come back to the new stable state. So our analogy is that being a ketoadaptive state is like living in a top of a steep sand dune; so it’s very hardto climb up, once you climb up and you are going to the top, you are stable andeasy to stay there. But you slide back down, it's hard to climb back again.
问： 关于长期维持低碳饮食，你有什么好的建议？什么事情最为重要呢？
Q: What are your best tips for people to make it easier to stay on this fora long time? What’s important to think about?
答： 有几点对于长期维持低碳饮食起着至关重要的作用。
首先，当一个人使用低碳饮食进行减肥，机体可以消耗一部分存储的脂肪。一旦机体适应了这种低碳的饮食方式，要维持这样稳定消耗脂肪的状态的关键是，他们在饮食不能再变回高碳饮食了。
同时，他们也只能吃适量的蛋白质，因为高蛋白饮食对于“酮症”状态具有抑制作用（尽管这种抑制效应不如碳水化合物来得强），为了维持稳定的生酮状态，我们就需要进行高脂肪饮食。以我为例，我每日摄入的75%到80%的热量来自于脂肪。
A: There are couple key points to make this kind of diet sustainable to beon a long term. First of all, when one is first on a low carb diet and losingweight, a fair amount of energy that burned each day comes from body fatstores. But once a person gets use to a new healthy way, the key to adaptestate is that they cannot add more carbohydrate. They should eat protein inmoderation because high protein intakes reduce ketones, though not efficientlyas carbohydrates. So in order to have a weight stable ketogenic diet, it mustbe a high-fat diet. In my case, I eat 75% to 80% of my daily energy comes fromfat.
问： 我想很多人对于低碳饮食或者阿特金斯饮食的理解是低碳高蛋白饮食，但这个跟你的观点有点背道而驰了，对吗？
Q: I think this is an important point because a lot of people think theAtkins diet or low-carb diets as high protein low carbohydrate diets. But thatis not quite true in your opinion, right?
答：是的！但你在看阿特金斯饮食的起始阶段的时候，你每天可能会摄入1400大卡的热量。
但是对于健康成年男性，基础代谢率可能是2800大卡每天，那么剩余的那1400大卡就要来源于身体的脂肪供能。
当你仔细看他摄入的营养成分时，其中600到800大卡的热量可能是来源于蛋白质。但是这600到800大卡的热量只是我们的嘴“看到的”，实际上嘴并没有“考虑到”我们内在消耗的那1400大卡的脂肪。
但是当你进入维持阶段的时候，你不再消耗机体内在的脂肪，你所用以功能的成分都来源于外来摄入的，所以此时你需要摄入更多的脂肪去维持机体的供能。
A: That’s true. When you look at the induction phase of Atkins which issomeone first starts the diet and who won’t intend to loss weight, they mighteat 1,400 calories per day. For a heavy man, his BMR might be 2,800 caloriesper day, so the other half is coming from body fat. So when you look at what’sthe person eats, if he eats 600 or 800 calories comes from protein, that lookslike a half protein diet. But that’s only what the mouth sees, what the body isseeing a moderate protein intake because the mouth isn’t seeing the half that’scoming from inside. But when you come to maintenance, it means you are notburning more body fat and that requires that all of the fat that you areburning has to come from outside.
问： 如果进行低碳水高蛋白饮食，会有什么影响吗？
Q: What happens to you for the new steady state when you do a low carb highprotein diet?
答： 我们可以做个简单的计算：如果我每天消耗2800大卡，其中有一半需要来自蛋白质供能（也就是1400大卡）。
先不说摄入这么多蛋白质需要花多少钱，就单单这么大量的蛋白质本身也可以让人觉得不舒服，会出现胃肠道不适、乏力、易疲劳。
因为摄入大量的蛋白质，机体不能很好地维持“生酮”状态，也就因而丧失了直接消耗脂肪的能力。
因为，想要长期维持能够令人满足的低碳饮食，我们就必须维持足够的血酮含量，进而维持大脑的能量供应，要维持低碳水、适量蛋白质，那么只有提高食物中脂肪的含量了。
这里我们可以举原住民（像猎人、牧人）文化的例子，他们通常不会在一个地方久住，因为也就没有办法耕种谷物。
再如因纽特人，因为极端的地理气候，他们没有办法耕种富含碳水的农作物，他们便选择用脂肪和肉类作为食物。
因纽特人通常会在驯鹿储存了大量脂肪准备过冬之前杀死它们，然后储存脂肪作为他们的能量来源，而将动物的瘦肉部分给他们的猎狗食用。
因而因纽特人的能量供应有75%到85%来源于脂肪，15%来源于蛋白质，而只有少于5%的是来自碳水化合物。
A: If you do the math, you would have to eat a whole lot of protein. Let’ssay I need to burn 2,800 calories per day and I want to eat half of that isprotein, that would be 1,400 calories per day is protein. It’s expensive, andthat level of protein intake make people feel sick, cause gastrointestinalupset, weakness, and fatigue. And that levels of protein protect body frombeing ketosis which means now you lost your easiest access to body fat stores,and you’ve allowed protein to be a metabolic impediment to block your access tofat. So make it sustainable a low carbohydrate diet satiating (means you aresatisfied) and to provide the right mix of fuel so that you keep making ketoneswhich keeps feeding the brain. You need to keep protein moderate and keep carbslow, so the only source of energy is fat. So when we look at the Aboriginalcultures, what do hunters and herders eat because they don’t stay in anylocation long enough to grow a crop, or people who live in an environment likethe Inuit where there are no investable carbohydrate foods. They choose not togather carb containing foods, but to eat only meat and fat which contain largeamount of fat and moderate amount of protein. The Inuit killed the caribou whenthe caribou are fat, then the lean parts were reserved to feed the dogs, whilethe high-fat foods were for human. So the Inuit eat 75% to 85% of fat, 15%protein and less than 5% carbs.
问： 如果因纽特人只摄入脂肪和肉类，他们会发生维生素C的缺乏症状吗？
Q: If you only eat fat and meat in the situation of Inuit, you don’t getlack of Vitamin C?
答： 目前我们还没有很好的答案。但是我们知道，1928年在贝尔维尤医院的研究结果显示，如果是摄入新鲜的肉类和脂肪，人类是不会发生坏血病的。有一个假说是我们之所以需要更高的维生素C，是因为我们摄入过多的碳水化合物，而高碳水可以引发机体发生氧化应激反应。
A: We don’t have a good answer for that now. But we do know that eatingfresh meat and fat doesn’t cause scurvy and that was a result of an experimentdone at Bellevue hospital in 1928. That raises one hypothesis that higheramount of Vitamin C is required because we eat a lot of carbohydrates and nowwe know that the carbohydrates increase the body’s level of oxidative stress.
问： 在接受人们可以很好地耐受低碳高脂饮食后，我们应该摄入什么样的脂肪呢？
Q: The another key point factor of maintaining low-carb diet for a longterm is if one accepts the fact that one can live well on high-fat moderatediet. The question is what kind of fat we should take.
答： 我们还以因纽特人为例，他们摄入的脂肪大多数是驯鹿体内的饱和及单不饱和脂肪酸，而他们有时候会将从海豹体内得到的多不饱和脂肪酸作为燃料。
现在我们知道，一旦机体适应了“酮症”状态，我们摄入的饱和脂肪酸就不会再被储存起来，而是作为一线的能量来源。当然，我们也需要摄入适量的必需脂肪酸，如omega-6 和omega-3，我们是没有必要摄入过多的不饱和脂肪酸。
A: People in Inuit situation, they choose fats that were rich in saturatedfats and mono-saturated fats like caribou, while use seal fats for their lamp.We now know that one person is keto adapted, one of the changes is that thesaturated fats are no longer accumulated, saturated fats become the body’spreferred first line fuel. The other fat is that we human needs some essentialfats each day, like omega-6 or omega-3, which are really modest. If you eat 75%or 80% calories, you don't need that much as a percentage.
问： 那你平时都吃什么食物呢？
Q: What do you eat mostly?
答： 我的脂肪来源主要是橄榄油、高油酸红花（富含单不饱和脂肪酸，并不含有omega-6等多不饱和脂肪酸）。我还会摄入肉、鱼、家禽，它们都含有脂肪部分。我也喜欢黄油、芝士等饱和脂肪酸。
A: In the facts, I choose olive oil, and high oleic safflower which is richin mono-saturated fats and doesn’t contain a lot of omega-6 and poly-saturated.I also eat a naturally occurring fats in the meat and fish and poultry. I alsoenjoy some butter, cheese that I don’t need to avoid since the saturated fatsare my body’s first line fuel.
问： 你知道在瑞典，我们称低碳饮食或者类阿特金斯饮食为LCHF（低碳高脂饮食）？因为只要我们正常摄入蛋白质，一旦减少了食物中的碳水化合物，我们就可以吃富含脂肪的食物，直到满足，对吗？
Q: Do you know in Sweden, we called low-carb diets or Askins-like diet asLCHF (meaning low-carb high-fat)? Since we always have a lot of protein, sowhat we need to do is keep the carbs low, and fill with fats until you aresatisfied, right?
答： 很正确！满足感是重中之重的，我从不计算我摄入的脂肪的量，我会吃到自己满足为止。近六年来，我的体重一直维持在比较稳定的水平。
A: That’s really accurate. The satisfaction is the key. I don’t count howmuch fat I eat; I just eat to be satisfied. For nearly six years, my bodyweight has been perfectly stable and I don’t change how much I eat.
问： 我听说你以前还有一些高血压的问题，对吗？
Q: You used to have some blood pressure mediation, right?
答： 是的。当我的饮食中还是部分碳水的时候（即使用Dash饮食法），我的血压一直在一个比较高的状态，需要采用药物治疗。但当我开始使用“低碳生酮”饮食后，我的血压就一直维持在正常低值。
A: That’s right. When I was on a carbohydrate containing diet, even a dashdiet, my blood pressure was in a range where it needed to be mediated. When Ijust stayed in a ketogenic diet, I have a low normal blood pressure.
总结来看，要想长期维持低碳饮食，我们就需要同时采取高饱和脂肪酸和单不饱和脂肪酸饮食，生酮饮食可以保证机体始终以脂肪作为主要的功能营养素。
低碳饮食的关键点还在于维持适量蛋白质摄入的同时，提高脂肪摄入，但也限制一些富含omega-6的植物油的摄入。在保证低碳（50g/天）的前提下，也可以吃一些低碳的蔬菜和浆果类的水果。
So anyway, to wrap it up, the tips for maintaining a low-carb for a longtime is fill up with fat issues saturated and mono-saturated fats. Keep carbslow, keep yourself at a range where you stay in nutritional ketosis whichallows the body to have free flow of fat fuel to all organs of the body. Tosatisfy oneself with moderate protein and high fat and make sure you eat theright kind of fat which is stay away from the liquid vegetable oils that arerich in omega-6. Also, eat a variety of fats if you wish even just for thetaste. One can also have some low-carbohydrate vegetables. For fruits, we cantake some berries which amount should be lower than 50 grams of carb.
最后的瘦龙说：
我知道，目前大部分人还只是希望通过低碳来减肥，后台问得最多的问题就是：
低碳一阵之后，恢复饮食，是不是非常容易反弹？
我的回答是：
如果你真正认真去认真体验低碳了，你真正体验到低碳的好处了，我相信你不会再想要恢复饮食了。
如果你只是想减个肥，不是真的想彻底改变自己的饮食结构，那么我建议你轻易不要尝试低碳，低碳是一种全新的饮食方式，如果你把他当做一种短期的减肥手段，带给你的可能就是暴食，反弹等等。
所以，如果你没有做好准备，就慢慢来吧，不要着急，如果暂时你做不到低碳，又想保持好的身材，那么你就多运动吧，多做一些力量训练，把摄入的碳水都消耗掉，可能会比较辛苦。
同时，通过艰难的运动去减肥，同样也需要用心去感受，也要把它当做一种新的生活方式，否则带给你的也是，过度运动后的暴食，和停止运动后的反弹。
视频中Stephen博士讲述的饮食习惯，是一种比较严格的低碳饮食方式，我目前还没有达到这样的境界，要养成这样的饮食习惯，可能需要花很多年。
如果你还还是忘不掉碳水，我还说建议大家一点点减少，不要奢望马上就达到这个境界。
我知道你们都听到过很多有关低碳的传言，导致没有月经不调，乏力，等等身体异常等等，这些都是很正常的初期不适是正常现象。
但是还有有很多不正常的现象，往往都是都是因为减肥者太极端而导致的，不考虑自己身体的感受，不知道如何正确的去执行低碳，眼里只有减肥目标，强行控制饮食，低碳还节食，不知道如何控制蛋白质和脂肪的量，等等。
把低碳变成一种，不计后果的极端减肥方式，是非常不可取的行为。
尝试去把低碳作为一种新的生活方式吧，不要只是用它来减肥，也许你会有一些不一样的感受。
（叨叨完了）
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