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When it comes to “going on a diet”, there are many well-trodden approaches. The traditional one, usually advocated by official policy makers, is to eat less and move more.
当谈到“节食”时,有很多被很好采用的方法。官方通常提倡的方法是少吃多动。

This advice is based on the first law of thermodynamics, a law that applies beautifully to internal combustion engines. Not so much human metabolism.
该建议基于热力学第一定律,非常适用于内燃机。不过人类没那么多的代谢。

Nevertheless, the simplicity of this theory is so intuitively appealing that it has endured, and continues to endure, despite all the evidence to the contrary. It assumes that obesity is a disorder of energy imbalance: when calories-in exceed calories-out, there is an energy surplus that the body stores as fat.
尽管有相反证据,但该理论如此简单又直观,以至于它能一直持续下去。它假设肥胖是一种能量失衡的疾病:当摄入的热量超过输出的热量时,身体会把多余的能量存储为脂肪。

“The ancient prescription of Hippocrates (400 BC) that the obese should eat less and exercise more continues nowadays to be a widespread approach for weight management despite its well-documented failures” (Dulloo et al 2012)
“尽管有可查数量的失败案例,希波克拉底的古老处方(公元前400年)所规定的少吃多运动依然成为今天广为流行的减肥方法。”

Perhaps you’ve already been there. Perhaps you already know that reducing the amount of food you eat starts well and ends badly. But you keep doing it anyway.
也许你这么做过,也许你已经知道减少食量开始很容易而结尾很痛苦,但你依然要坚持这么做。

Don’t be too hard on yourselves, you regressors: counting calories is what you have been instructed to do, and what you have done, for longer than you care to remember, to little or no effect. Or rather, to great effect — at first. You reduce your calorie intake substantially, and quickly lose weight. Marvellous! You’re hungry, pretty much all the time, but the system’s working and you’ve got the willpower.
不要对自己太严苛,理性分析:计算卡路里是你被要求做的事情,也是你在做的事情,你坚持的时间越长,效果就越小,甚至没有效果。更确切地说,起初效果很明显,你可以大大减少卡路里的摄入,并迅速减重。你几乎一直都在挨饿,但身体系统一直在运行,这让你有了毅力。

But soon enough your weight reaches that inevitable plateau. What’s more, your hunger is now raging, gnawing at both your stomach and your resolve.
但是很快,你的体重就到了平台。何况,你还觉得饿,这会伤害你的胃,并影响你继续下去的决心。

You can only keep this up for so long, as every hard-boiled dieter will concur. You really do have to get off this treadmill.
你只能坚持这么久,每个节食者都会同意,你不得不从跑步机上下来。

Numerous studies have concluded that dieting is associated with long term weight gain. This phenomenon has even been given a scientific name: fat overshooting.
许多研究已经得出结论,节食与长期的体重增加有关。这种现象甚至被命上学名:脂肪超调。

“The long-term result of dieting thus may paradoxically be the opposite of the desired goal” (Pietiläinen et al).
“因此,长期节食可能会引起与期望相反的结果。”

This apparent paradox is attributed to a decrease in resting energy expenditure and “adaptive thermogenesis”, as the body (the thyroid gland) adjusts its metabolic rate to match the reduction in calorie intake.
这种矛盾归因于静息能量消耗的减少和 “代谢的适应性 ”,因为身体(甲状腺)会调节身体的代谢率来适应卡路里摄入量的减少。

It doesn’t have to be like this. The long-term solution is easier, more effective and evidence based. It involves these three principles:
不一定都要这样。长期的减肥方法更容易,更有效且基于一定的证据。它包括以下三个原则:

  1. When you cut out unnecessary carbohydrates, you burn body fat
    当你舍弃不必要的碳水化合物时,会燃烧体内的脂肪。
  2. When you eat fat, you burn fat.
    当你吃脂肪时,你也在燃烧脂肪。
  3. When you eat protein, you stay full for much longer.
    当你吃蛋白质时,你会更长时间不觉得饿。

And so to the science.
科学也是如此

Cutting out carbs
减少碳水

A low carbohydrate diet works because it reduces insulin secretion and stimulates the release of fat from storage.
低碳饮食之所以起作用,是因为它减少了胰岛素的分泌并刺激存储的脂肪来消耗。

That’s certainly true of insulin. Without this hormone you’re either dead or diabetic, but too much can make you fat and sick.
胰岛素当然是正确的。没有这种激素,你可能已经死了或有糖尿病,但是过多的胰岛素会让你发胖和生病。

Insulin is the great multi-tasker, performing numerous important functions in the body. But in terms of weight management it has three major roles, as explained below.
胰岛素是出色的多任务处理者,在体内执行许多重要功能。但是就体重管理而言,它具有三个主要作用,如下所述。

First, insulin regulates blood sugar. Insulin is released by the pancreas when food enters the stomach, and nothing stimulates this hormone quite like carbohydrate. Carbohydrates include cereals and other starchy grains, bread, pasta, pastries, potatoes, and sweet and savoury snacks.
首先,胰岛素能调节血糖。食物进入胃时,胰腺会释放出胰岛素,碳水化合物能刺激这种激素。碳水化合物包括谷物和其他淀粉类的食物,如面包,面食,糕点,土豆以及咸味小吃。

Eat carbohydrates and your digestive system will get to work, breaking them down into smaller molecules of glucose and then transporting those molecules through the gut lining into the bloodstream. The more carbohydrate you eat, the more glucose enters the blood.
吃碳水化合物,消化系统就会起作用,将其分解成较小的葡萄糖分子,然后将这些分子通过肠壁运输到血液中。你吃的碳水越多,就有越多的葡萄糖进入血液。

This glucose, or sugar, needs to be tightly regulated. Too much and you are in potential danger. You have only (or should have only) around a teaspoon-worth of sugar coursing through your blood vessels at any given time.
需要严格控制这种葡萄糖或糖的摄入量。太多,你有潜在危险,任何时间,你只有(或应该只有)一茶匙的糖流经血管。

This is where insulin comes in. It takes surplus glucose and sends it off for storage in your muscles and liver, where it becomes known as glycogen. When these depositories are full — and they have limited storage capacity — off goes that surplus glucose to your adipose tissue, aka body fat.
这就是胰岛素的来源。它吸收多余的葡萄糖,然后将其发送出去,储存在肌肉和肝脏中,也被称为糖原。当这些存储库已满——存储容量有限——多余的葡萄糖就会流向你的脂肪组织,也就是人体脂肪。

It’s the horrid inevitability of eating lots of carbs.
这就是摄入大量碳水的可怕结果。

Thus, the second main role of insulin concerns fat storage. You only have room for around 2,000 calories-worth of glycogen in your muscles and liver, but the storage capacity of your adipose tissue is prodigious.
所以胰岛素的第二个作用就涉及脂肪的储存。你的肌肉和肝脏中只有约2000卡路里的糖原,但脂肪组织的储存能力却是巨大的。

The third role of insulin is to block the flow of fat out of adipose tissue. All that guff you have heard about carbohydrate being the body’s “preferred” fuel is utter nonsense. Your body will always burn carbohydrate first, not because it loves it more than anything else but because circulating glucose is potentially lethal if it is not dealt with immediately.
胰岛素的第三个作用是阻止脂肪从脂肪组织中流出。你听到的所有关于碳水化合物是人体“首选”燃料的说法都是胡说八道的。你的身体总是会先燃烧碳水,这不是因为更爱碳水,而是因为如果不立即处理碳水,循环葡萄糖可能会致命。

If you continue to eat lots of carbohydrates, your fat stores will remain locked away. You won’t burn your stored fat because there’s no requirement to do so. When glucose from carbohydrate is not available, your body is only too happy to burn fat instead.
如果你继续大量摄入碳水,你的脂肪存储区会保持封锁。你不会再燃烧储存的脂肪,因为身体不需要这样做了。如果无法从碳水中获得葡萄糖,那身体就会燃烧脂肪。

Eating fat to burn fat
吃脂肪是为了燃烧脂肪

For years, you’ve been told that in order to burn fat you have to avoid fat. It seems logical, so you have sacrificed flavour — because that’s what fat provides — to achieve your weight loss goal. You’ve even convinced yourself that those fat-free options are delicious, despite their disappointing aftertaste.
多年来,你被告知要燃脂就必须避免摄入脂肪。这似乎是合乎逻辑的,所以你为了减肥而牺牲口味-因为这就是脂肪所提供的。你甚至说服自己——尽管吃起来很痛苦,但无脂肪的选择是美味的。

No gain without pain, right? Wrong — because if you want to burn fat, it is essential that you eat fat. Your goal is to burn the surplus fat that sits in your adipose tissue. Surplus energy is there to be drawn on when necessary. The trick is to make it necessary.
一分耕耘一分收获,对吗?错的-因为如果你想燃烧脂肪,那么必须食用脂肪。你的目标是燃烧多余的脂肪。需要时确实可以燃烧多余的能量,所以诀窍是让它们成为必需。

When your diet consists predominantly of fat (and protein) with very low carbohydrate, you switch from burning glucose to burning fatty acids and ketones, made from your body fat. That is why a low carbohydrate, high fat diet is sometimes referred to as a ketogenic diet.
当你的饮食主要由脂肪、蛋白质和非常低的碳水组成时,你会从燃烧葡萄糖转换为燃烧由人体脂肪制成的脂肪酸和酮。这就是为什么低碳高脂的饮食方法有时也被称为生酮饮食。

Studies reveal that in the short term, there is no significant difference in the efficacy of a low carbohydrate diet or low-calorie diet. It’s in the long-term that the ketogenic diet comes into its own, and emerges as the superior system.
研究表明,短期看,低碳饮食或低热量饮食的效果没有显著差异。而长期看,生酮饮食应运而生,且成为了高级系统。

A systematic review investigated whether a very low carbohydrate ketogenic diet achieved better weight loss in the long term (and had better effects on cardiovascular health) than a low-fat diet. The researchers trawled through thirteen, high quality studies that had a duration period of at least 12 months. They found that those on the high fat diet achieved the greatest weight loss in the long term.
一项系统的综述调查了低碳的生酮饮食在长期内是否比低脂饮食达到了更好的减肥效果(并对心血管健康的效果更好)。研究人员至少持续了12个月对这项研究进行13项高质量的研究。他们发现,长期来看,高脂饮食的人减重最多最大。(Bueno等人,2013年)

What constitutes a low-carbohydrate diet? There is no official definition, but less than 50g/day is generally accepted as low carbohdyrate. Less than 30g/day is considered a very low carbohydrate diet.
什么是低碳饮食?尚无官方定义,但广泛接受的是每天少于50g的碳水。每天少于30g被认为是极低的碳水饮食。

Eating more protein
多吃蛋白质

It is every dieter’s dream to have an appetite that is totally and painlessly under control. Welcome to protein.
完全无压力地控制食欲是每个节食者的梦想。欢迎使用蛋白质。

A higher protein diet by-passes the pain of weight loss. It not only keeps your appetite satisfied for longer, it promotes good health and vitality too.
高蛋白饮食可以减少减肥的痛苦。它不仅可以使你的食欲持续更长久,还可以促进身体健康和活力。

There are two extraordinary ways in which it does this.
它可以通过两种不同的方式来执行。

Protein Magics Away Appetite
蛋白质可以使食欲不振

Protein is more filling than fat, despite containing fewer calories per gram. In studies, a diet consisting of 30% protein has been found to markedly increase fullness, and to lead to less desire to eat.
尽管每克热量较少,但蛋白质比脂肪更饱满。在研究中,发现由30%的蛋白质组成的饮食结构可显著增强饱腹感,减少进食欲望。

How does protein do this? The answer lies in its ability to influence certain hormones that regulate appetite. One of these hormones is ghrelin.
蛋白质如何做到这一点?答案在于它影响了某些调节食欲的激素,其中一个是胃饥饿素。

Ghrelin is secreted in the stomach and stimulates appetite by acting as a hunger signal to the brain. Therefore, as you’d expect, levels of ghrelin rise when you reduce your calorie intake.
胃饥饿素分泌在胃中,并通过向大脑发出饥饿信号来刺激食欲。正如你所期望的那样,减少卡路里摄入量时,胃饥饿素水平会上升。

Protein suppresses concentrations of this hormone once you have finished eating, and for prolonged periods thereafter.
一旦你吃完了,蛋白质就会抑制这种激素的产生,并持续很长时间。

“Higher protein weight-loss diets have led to beneficial reductions in body weight, fat mass, and food intake, while preserving lean body mass, and improving satiety in overweight and/or obese individuals. Because of these benefits, higher protein diets are potentially a preferable dietary strategy in combating obesity than traditional reduced energy diets.”
“高蛋白减肥饮食已导致体重、脂肪和食物摄入量的有益减少,同时保持了瘦体重,并改善了超重和/或肥胖个体的饱腹感。由于这些好处,与传统的低热量饮食相比,高蛋白饮食在对抗肥胖方面是一种更可取的饮食策略。”
Protein also increases levels of two key hormones that work in opposition to ghrelin, by suppressing hunger: polypeptide YY (PYY) and cholecystokinin (CCK).
蛋白质还可以通过抑制饥饿来增加与胃饥饿素相对的两种激素的水平:多肽YY(PYY)和胆囊收缩素(CCK)。

PYY is secreted along the digestive tract; levels increase after eating, and decrease during fasting.
多肽沿消化道分泌,进食后水平升高,禁食时水平降低。

CCK is stimulated by both protein and fat, and makes you feel full by slowing down the rate at which food passes out of the stomach (‘gastric emptying’ is the terminology). PYY can have a pronounced effect on the desire to eat.
胆囊收缩素受到蛋白质和脂肪的刺激,并通过减慢食物从胃中流出的速度而使你感到饱腹(“胃排空”是术语)。胆囊收缩素可以对饮食欲望产生显著影响。

CCK has been the subject of some intense research over the last thirty years, mainly because of its influence on the gut-brain connection. It is found throughout the small intestine, and is released after eating. In the same way that ghrelin can increase appetite, CCK induces the feeling of fullness.
在过去的30年中, 胆囊收缩素一直是深入研究的主题,这主要是由于胆囊收缩素对肠-脑连接的影响。它遍布整个小肠,在进食后释放。和胃饥饿素可以增加食欲一样,胆囊收缩素可以引发饱腹感。

Protein burns fat faster
蛋白质燃烧脂肪更快

A high protein diet not only promotes appetite control, it speeds up fat burning. It does this by increasing your resting metabolic rate. What’s more, this effect is immediate, which is terrific because you want to lose weight in the here and now, not on another time and space continuum.
高蛋白饮食不仅可以促进食欲的控制,还可以加速燃烧脂肪。通过增加静息代谢率来做到这点。而且,这种效果是立竿见影的,这非常了不起,因为你在此时此地减肥,而不是在他时他地。

When a group of 130 men and women aged 40–56 were given either a high protein, low carbohydrate diet, or a low protein, high carbohydrate diet, for four months, those in the high protein group lost 22% more fat mass than the high carbohydrate group, even though these two groups consumed the same number of calories throughout. As the researchers conclude:
当一组130位年龄在40-56岁之间的男女性分成两组,分别接受高蛋白、低碳水的饮食组合和低蛋白、高碳水的饮食组合,四个月后,即使这两个组在整个过程中消耗了相同的卡路里,高蛋白组的人比高碳水的人多减少了22%的脂肪。研究人员得出的结论是:

“positive outcomes associated with increased dietary protein are thought to be due primarily to lower energy intake associated with increased satiety, reduced energy efficiency and/or increased thermogenesis, positive effects on body composition, specifically lean muscle mass, and enhanced glycemic control.”
蛋白质增加的饮食习惯产生的正面结果,主要是由饱腹感增加、能量效率降低、产热相关的能量摄入减少导致,这会对身体产生积极影响,特别对瘦肌肉质量,还能增强血糖的控制。

What protein?
什么是蛋白质?

The best quality sources of protein are meat, fish, seafood, eggs and cheese. The best plant protein for vegetarians is nuts, such as cashews, hazelnuts, walnuts and pecans, as they are a combination of fat and protein. The problem with other plant-based sources of protein is that they almost always contain high amounts of carbohydrate, which is what you are trying to avoid.
蛋白质最好的来源是肉,鱼,海鲜,鸡蛋和奶酪。素食者最好的植物蛋白是坚果,例如腰果,榛子,核桃和山核桃,因为它们是脂肪和蛋白质的结合体。其他的植物蛋白的问题是它们几乎都含有大量的碳水,而这是你要避免的。

Take quinoa, often suggested as an ideal source of vegetarian protein. The truth is it contains only 14% protein: the rest is mainly carbohydrate.
以藜麦为例,通常建议将它作为素食蛋白质的理想来源。而事实上,它仅包含14%的蛋白质,其余的主要是碳水。

When you combine protein with high amounts of fat, and as little carbohydrate as possible, weight loss is accelerated, and feels effortless.
当你将蛋白质与大量脂肪和少量碳水结合在一起时,减重会加速,并且感觉这很轻松。

That is the fundamental science of successful, long-term weight loss. But to complete the package, there’s one more important consideration. The timing of your meals, and when and how you sleep are both crucial elements of fat burning metabolism. You need to make sure you are aligned with your body clock — aka circadian rhythm - in order to trigger the hormones that stimulate fat burning.
这是成功、长期减肥的基础科学。但要完成整个过程,还有个更重要的因素。你的吃饭时间和何时睡觉都是燃烧脂肪的关键因素。你需要与自己的生物钟保持一致(也称为昼夜节律),这样才能触发使脂肪燃烧的激素。