作者： Atman语言智能 来源： Atman语言智能

《减肥很难》

(CNN) —如果您认为减肥并保持体重很难，那么您并不孤单 — 而且您也是 100% 正确的。研究发现，长期减肥确实很难实现。

虽然估计有所不同，但据信超过 80%的体重大幅减轻的人会在五年内恢复体重。

但减肥失败往往并不是因为缺乏改变生活方式的意志力，比如健康饮食、减少热量摄入和增加体力活动。肮脏的小秘密是，我们的身体在进化过程中会储存脂肪。

古人类学家丹尼尔·利伯曼 (Daniel Lieberman) 最近在播客《追逐生命》中对 CNN 首席医学记者桑杰·古普塔 (Sanjay Gupta) 博士说：“我们进化到并不是故意减肥。” 利伯曼是哈佛大学人类进化生物学系教授兼系主任，他研究人体的外观和功能为何如此。

“所有动物都需要一些脂肪，但人类已经进化到脂肪含量异常高，即使是瘦弱的人类，”他说。“因此，我们总是承受着特殊的生物压力，只要我们有它，我们就必须戴上它并保留它，以备不时之需。”

利伯曼说，人类从根本上适应的不是为了快乐或健康，而是为了繁殖成功。为此，我们需要脂肪，大量的脂肪——这就是为什么利伯曼称人类与其他哺乳动物，甚至其他灵长类动物相比，是“异常肥胖的物种”。

“我们有这么大的大脑，这需要消耗大量的能量。……它占我们新陈代谢的 20%，”他说。“而一个婴儿，当它出生时，一半的能量都在为大脑提供能量。它需要大量的脂肪。所以……人类婴儿出生时就非常胖，因为他们必须拥有能量来确保他们的大脑能够运转。”

利伯曼说脂肪是可储存的能量。它帮助早期人类生存，为他们的身体提供寻找食物的动力，保持他们的大脑正常工作，并使 他们足够健康以进行繁殖。

“这就像银行账户里的钱一样。因此，在我们的进化史上，拥有适当脂肪水平的个体比那些没有适当脂肪水平的个体表现得更好，”他说。“所以我们被选中是为了确保我们总能穿上它，因为总有时候我们不得不失去它。”

利伯曼说，人类从来没有进化到刻意减肥。

虽然我们的身体并没有真正从早期进化而来，但我们的环境——也就是利伯曼所说的——存在很大的不匹配。如今，我们不必躲避野生动物，不必长途跋涉，也不必狩猎和采集下一顿饭。我们可以拿起智能手机拨打 Uber 或 Uber Eats 优食，体验各种现代便利设施。结果，许多人现在面临体重问题和肥胖，以及由此产生的所有“失配疾病”。

利伯曼说：“因此，失配疾病被定义为当我们生活在我们适应不良或不充分的环境中时，这些病症或疾病会更常见或更严重。”他指的是我们现代的“致肥胖环境”，这种环境往往会导致肥胖。体重增加。

“所以，当然，这很难。这是因为我们进化到不刻意减肥。因此，减肥需要节食，需要欺骗你的身体并克服这些适应——你的身体会一路与你作斗争。”

利伯曼表示，我们需要对那些面临体重挑战的人（包括我们自己）“极其富有同情心”，他建议牢记以下五件事：

发展（进化）观点

并非所有人类都注定是简笔人物或苗条的流浪汉——无论你在电视、电影或社交媒体上看到什么。

“脂肪对人类尤其重要，”利伯曼在一封电子邮件中写道。“即使是瘦人，体内脂肪也有 15-25%，是大多数哺乳动物的三到四倍。”

你总会有一定量的脂肪， 并且在某些方面是必要的。

脂肪等于进化成功

脂肪实际上可以帮助我们生存和发展。

利伯曼说：“由于我们的身体和生活史消耗了大量的能量，我们进化出了储存大量脂肪的能力，脂肪是储存能量的来源。” “这些脂肪有助于为我们的大大脑提供燃料，并降低我们高昂的繁殖成本，同时保持身体活跃。”

即便如此，“我们从来没有进化到储存大量腹部脂肪，这会导致健康问题，”利伯曼指出。“所以中间有很多脂肪是做某事的标志。”

小幅波动属于正常现象

如果您的体重在短时间内上升或下降几磅，请不要担心。

“这种变化很大程度上是由水造成的，”利伯曼说。“在人类历史的大部分时间里，人们经常会经历摄入的能量多于消耗的能量的时期，并将多余的能量储存为脂肪，然后在消耗的能量多于消耗的能量的贫乏时期利用这些脂肪储备。”

牌组确实对你不利

如果你发现减肥很难，不要责怪自己。

“人类进化到尽可能储存大量脂肪，然后在需要时使用它，”利伯曼说。“但我们从未进化到自愿消耗比我们使用的能量更少的能量——即饮食。”

利伯曼说，节食会引发身体的饥饿反应，导致节食者渴望食物，并通过减慢新陈代谢来节省能量。“因此，当人们节食时，他们几乎总是在努力克服古老的基本适应，以防止身体减肥，”他补充道。

节食与运动

如果您想知道锻炼和节食哪个对减肥更重要，答案是两者都重要，但原因不同。

利伯曼说：“通过节食比运动更能减轻体重。” “但锻炼有助于防止体重增加或反弹，而且它对身心健康还有很多很多其他好处。”

至于我们石器时代的身体与现代肥胖环境之间的不匹配，利伯曼说，我们必须“弄清楚如何设计我们的世界，以帮助我们做出我们想要做出的选择。”

原文

Editor’s note: Season 9 of the podcast Chasing Life With Dr. Sanjay Gupta explores the intersection between body weight and health. We delve into a slew of topics, including new weight loss drugs and how to talk to kids about weight. You can listen here.

(CNN) — If you think it’s hard to lose weight and keep it off, you are not alone — and you are also 100% correct. Long-term weight loss is really difficult to achieve, studies have found.

Estimates vary, but it’s believed that more than 80% of people who lose a substantial amount of weight regain it within five years.

But failure to shed pounds is often not about lacking the willpower to make important lifestyle changes, such as eating healthier, reducing calories and increasing physical activity. The dirty little secret is that our bodies are programmed by evolution to hold on to fat.

“We evolved not to lose weight intentionally,” paleoanthropologist Daniel Lieberman told CNN Chief Medical Correspondent Dr. Sanjay Gupta recently on the podcast Chasing Life. Lieberman, a professor and chair of the department of human evolutionary biology at Harvard University, studies why the human body looks and functions the way it does.

“All animals need some fat, but humans have evolved to have exceptionally high levels of fat, even thin humans,” he said. “And so we are under exceptional sort of biological pressure, always, to put it on and keep it as long as we have it, for when we need it.”

Humans are fundamentally adapted not to be happy or healthy but rather to be reproductively successful, Lieberman said. And for that, we need fat, a lot of fat — which is why Lieberman calls humans “an unusually fat species” compared with other mammals, even other primates.

“We have these big brains, which cost a huge amount of energy. … It’s 20% of our metabolism,” he said. “And a baby, when it’s born, half of its energy is paying for its brain. It needs a lot of fat. So … human babies are born very fat because they have to have that energy to make sure that they can keep their brain going.”

Lieberman said fat is storable energy. It helped early humans stay alive, powered their bodies to find food, kept their brains working and made them healthy enough to reproduce.

“It’s like money in the bank account. And so individuals who have appropriate levels of fat did better in our evolutionary history than those who didn’t,” he said. “And so we were selected to make sure that we always could put it on, because there were always times when we had to lose it.”

Lieberman said humans never evolved to lose weight deliberately.

And while our bodies haven’t really evolved from those earlier times, our environment has — and that is, what Lieberman called, a big mismatch. Nowadays, we don’t have to run from wild animals, travel long distances on foot, or hunt and gather our next meal. We can pick up a smartphone to call an Uber or Uber Eats and experience all manner of modern conveniences. As a result, many people now live with weight issues and obesity, and all of the “mismatch diseases” that stem from that.

“So mismatch diseases are defined as conditions or diseases that are more common or more severe when we live in environments for which we’re poorly or inadequately adapted,” Lieberman said, referring to our modern-day “obesogenic environment” that often contributes to weight gain.

“And so, of course, it’s hard. It’s because we evolved not to lose weight intentionally. And so, losing weight requires dieting, requires tricking your body and overcoming those adaptations — which your body’s going to fight you every, every inch of the way.”

Lieberman, who said we need to be “extremely compassionate” toward those who face weight challenges, including ourselves, suggests keeping these five things in mind:

Develop (evolutionary) perspective

Not all humans are meant to be stick figures or willowy waifs — no matter what you see on television, at the movies or on social media.

“Fat is especially important for humans,” Lieberman wrote in an email. “Even thin humans have between 15-25% body fat, which is three to four times more than most mammals.”

You will always have a certain amount of fat, and it is necessary in some ways.

Fat equals evolutionary success

Fat actually helps us survive and thrive.

“We evolved to store a lot of fat — a source of stored energy — because of our energetically expensive bodies and life history,” Lieberman said. “That fat helps fuel our big brains and our high cost of reproduction all while staying physically active.”

Even so, “we never evolved to store a lot of belly fat, which can lead to health problems,” Lieberman pointed out. “So having a lot of fat around the middle is a sign to do something.”

Small fluctuations are normal

Don’t worry if your weight goes up and down a few pounds over short periods of time.

“Much of that variation is due to water,” Lieberman said. “For most of human history people regularly cycled through times when they took in more energy than they used and stored the surplus as fat and then drew on those fat reserves during lean times when they used more energy than they consumed.”

The deck really is stacked against you

If you find it hard to lose weight, don’t blame yourself.

“Humans evolved to store plenty of fat when possible and then use it when needed,” Lieberman said. “But we never evolved to voluntarily consume less energy than we used — that is, diet.”

Lieberman said dieting triggers the body’s starvation responses that cause dieters to crave food and save energy by slowing down their metabolism. “So when people diet, they almost always struggle to overcome ancient, fundamental adaptations to prevent their bodies from losing weight,” he added.

Dieting versus exercise

If you are wondering which is more important for weight loss — exercise or dieting — the answer is both, but for different reasons.

“You can lose more weight by dieting than exercising,” Lieberman said. “But exercise helps prevent gaining or regaining weight, plus it has many, many other benefits for both mental and physical health.”

And as for that mismatch between our Stone Age bodies and our modern, obesogenic environment, Lieberman said we have to “figure out how to engineer our worlds to help us make the choices that we would like to make.”

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内容来源|https://edition.cnn.com/2024/01/26/health/weight-loss-hard-evolution-wellness/index.htmlzh-CN

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