吃肉对你有害吗？肉类真的不健康吗？：英语精读讲义

When our vegetarian ancestors started eating meat around 2 million years ago,

当我们吃素的祖先在大约200万年前开始吃肉时，

it wasn't just because animals taste great. 語法

并不只是因为肉的味道好。

It was pure necessity.

这完全是出于生存需要。

Climate change made many of the plants our ancestors relied on less available

气候变化导致我们祖先赖以生存的许多植物变得稀缺，

and meat bridged that gap. 習語

而肉类填补了这一空白。

From the discovery of fire at the latest, 短語搭配

最晚从发现火开始，

meat became a staple of the human diet. 用詞

肉类就成了人类饮食的主食。

But over the last few years,

但在过去几年里，

eating meat has increasingly been associated with health risks like heart disease, 短語搭配

吃肉越来越多地与心脏病等健康风险、

certain cancers,

某些癌症，

and an early death.

以及早逝联系在一起。

So, how unhealthy is meat really?

那么，吃肉到底有多不健康呢？

In this video,

在这个视频中，

we'll only talk about meat.

我们只讨论肉类。

Dairy products deserve a video of their own. 短語搭配

奶制品值得单独做一期视频。

Biologically,

从生物学角度来说，

we need to eat for three reasons:

我们吃东西有三个原因：

for energy,

为了获取能量，

to acquire materials to fabricate our cells

获取制造细胞的物质，

and to get special molecules that our bodies can't make themselves.

以及获取我们身体无法自行制造的特殊分子。

The energy and most of the materials come from the three macronutrients:

能量和大部分物质来自三大常量营养素：

fats,

脂肪，

carbohydrates,

碳水化合物，

and proteins.

和蛋白质。

Proteins are the most important resource for repairing and replenishing our cell structures.

蛋白质是修复和补充我们细胞结构的最重要资源。

The special molecules are a large variety of vitamins and minerals we need to drive metabolic processes. 短語搭配

特殊分子是我们推动代谢过程所需的各种维生素和矿物质。

Meat provides us with most of these things. 短語搭配

肉类为我们提供了其中的大部分。

It contains all essential amino acids our body needs

它包含了我们身体所需的所有必需氨基酸，

and a lot of minerals like iron,

还有大量矿物质，如铁、

zinc,

锌，

and essential vitamins,

和必需维生素，

some of which are barely found in plants like vitamin B12. 語法

其中一些在植物中几乎找不到，比如维生素B12。

Only one essential nutrient is missing in most of the meat we consume,

我们食用的大多数肉类中只缺少一种必需营养素，

vitamin C.

维生素C。

It appears in almost all plants and supports our immune system as well as the development of connective tissues. 短語搭配

它几乎存在于所有植物中，支持我们的免疫系统以及结缔组织的发育。

After a few months without it,

如果几个月不摄入它，

you'd get scurvy.

你就会得坏血病。

But meat has another big advantage:

但肉类还有一个很大的优势：

its high bioavailability. 用詞

其高生物利用度。

Some of the nutrients in meat are broken down faster and available quicker than those from plants. 短語動詞

肉类中的一些营养物质比植物中的营养物质分解得更快，也能更快被吸收。

Spinach,

菠菜，

for example,

举个例子，

contains more iron than meat,

含有比肉类更多的铁，

but it's absorbed much slower and the body needs more energy to digest it.

但它吸收得慢得多，且身体需要消耗更多能量来消化它。

Several health benefits have also been observed in communities that rely solely on meat.

在完全依赖肉类的社区中，人们也观察到了一些健康益处。

The Inuit, 文化背景

因纽特人，

for example,

举个例子，

are able to survive in extreme climate conditions on a purely meat-based diet,

能够在极端气候条件下，依靠纯肉食生存下来，

if necessary.

如果有必要的话。

Since they consume the whole animal,

因为他们会吃掉整只动物，

including the organs,

包括内脏，

they get every single nutrient they need,

他们获得了所需的每一种营养素，

including vitamin C.

包括维生素C。

So,

所以，

meat itself is definitely not dangerous for us,

肉类本身对我们绝对不危险，

but its health effects vary depending on how it's prepared and what animal it comes from. 語法

但它的健康影响因烹饪方式和肉类来源而异。

When talking about meat in the Western world, 語法

当在西方世界谈论肉类时，

we generally mean muscle tissues that have a high nutrient density,

我们通常指的是营养密度高的肌肉组织，

but also lack some of the vitamins that make it possible to survive on meat alone. 語法

但它也缺乏一些能让人仅靠吃肉生存的维生素。

The most healthy animals to eat are probably fish.

最健康的肉类可能就是鱼了。

Fish contains polyunsaturated fatty acids like omega-3,

鱼类含有多不饱和脂肪酸，如欧米伽-3，

which may lower the risk of cardiovascular diseases and support anti-inflammatory immune functions.

可以降低患心血管疾病的风险，并支持抗炎的免疫功能。

As part of a balanced diet,

作为均衡饮食的一部分，

fish can be eaten regularly without worries.

可以经常吃鱼而不用担心。

Eating fish comes with its own bag of complications, 習語

不过吃鱼也有其自身的一系列复杂问题，

though,

然而，

like overfishing and the destruction of the oceans.

比如过度捕捞和海洋生态破坏。

We'll talk about that in another video.

我们会在另一个视频中讨论这个问题。

A close second is the most popular meat, 短語搭配

紧随其后的是最受欢迎的肉类，

chicken.

鸡肉。

It's regarded as the meat with the fewest health risks. 短語搭配

它被认为是健康风险最低的肉类。

The only negative health effect of poultry is a bit controversial,

禽肉唯一的负面健康影响存在一些争议，

fat.

那就是脂肪。

Its high content of saturated fat is associated with a higher cholesterol level and cardiovascular disease.

其高饱和脂肪含量与较高的胆固醇水平和心血管疾病有关。

But this idea has also been criticized by a large number of scientists,

但这种观点也受到了大量科学家的批评，

arguing high cholesterol levels might be inherited and not caused by nutrition. 語法

他们认为高胆固醇可能是遗传的，而不是由饮食引起的。

So, in general,

所以，总的来说，

if you want meat and are concerned about your health,

如果你想吃肉又关心健康，

go for chicken. 短語動詞

就选鸡肉吧。

Things start to get problematic with high intakes of red meats like beef,

当大量摄入红肉时，事情就开始变得有问题了，比如牛肉、

veal,

小牛肉、

pork,

猪肉、

lamb,

羊肉、

horse,

马肉，

and goat.

和山羊肉。

A recently published study recommends,

一项最近发表的研究建议，

for example,

举例来说，

a maximum of 23 grams of red meat per day,

每天最多摄入23克红肉，

which is a very small steak per week.

也就是每周一小块牛排的量。

However,

然而，

large-scale meta-analysis studies have shown that eating 100 grams of red meat every day 用詞

大规模的荟萃分析研究表明，每天吃100克红肉

increases the relative risk of diabetes by 19%, 用詞

会使患糖尿病的相对风险增加19%，

of strokes by 11%,

中风风险增加11%，

and of colorectal cancer by 17%.

结直肠癌风险增加17%。

This sounds alarming,

这听起来很可怕，

but before we panic, 表達脈絡

但在我们恐慌之前，

let's have a look at how these studies were conducted.

让我们看看这些研究是如何进行的。

Because this brings us to the second big problem 表達脈絡

因为这就引出了第二个大问题，

when trying to answer the question

当试图回答这个疑问时，

of whether meat is unhealthy or not. 語法

即吃肉是否不健康。

Most studies that linked health risks to eating red meat

大多数将健康风险与吃红肉联系起来的研究

were case-control studies, 文化背景

都是病例对照研究，

which means taking a group of people with a disease

意思是选取一群患有某种疾病的人，

and classifying them by their eating habits.

并根据他们的饮食习惯进行分类。

The more red meat they consume, 語法

他们摄入的红肉越多，

the more likely they were to contract certain diseases.

感染某些疾病的可能性就越大。

The problem is that it's very hard to eliminate other factors. 用詞

问题是，很难排除其他因素。

People who eat less meat

吃肉较少的人

tend to live a healthier lifestyle in general. 語法

通常也会保持更健康的生活方式。

They tend to eat more vegetables and fruit

他们往往吃更多的蔬菜和水果，

and are less likely to smoke and drink alcohol. 語法

并且吸烟和喝酒的可能性更小。

Most studies try to eliminate these factors,

大多数研究试图排除这些因素，

but it's extremely hard to make definitive statements. 短語搭配

但极难得出决定性的结论。

Things get worse when we look at processed

当我们看到加工

meat, though.

肉类时，情况就更糟了。

Processing meat means adding certain chemicals

加工肉类意味着添加某些化学物质，

by curing, 語法

通过腌制、

smoking,

烟熏、

salting,

盐渍，

or fermenting.

或发酵。

Or,

或者，

in other words, 表達脈絡

换句话说，

making it delicious.

把它变得美味。

Bacon,

培根、

ham,

火腿、

salami,

萨拉米香肠、

sausages,

香肠，

and hot dogs contain chemicals that are harmful for us,

和热狗含有对我们有害的化学物质，

like nitrates and nitrites

比如硝酸盐和亚硝酸盐，

that can damage the DNA in our digestive system

它们会破坏我们消化系统中的DNA，

and lead to cancer.

并导致癌症。

The WHO reviewed 800 studies over 20 years

世界卫生组织（WHO）审查了20年来的800项研究，

and concluded that processed meat is strongly linked to an increased risk of colorectal cancer. 短語搭配

得出结论：加工肉类与结直肠癌风险的增加密切相关。

Each extra 50 grams of processed meat per day increases your relative risk of cancer by 18%.

每天每多吃50克加工肉类，患癌的相对风险就会增加18%。

When it comes to cancer risk,

在致癌风险方面，

processed meat is now in the same category as plutonium, 短語搭配

加工肉类现在与钚、

asbestos,

石棉，

and smoking.

和吸烟同属一类。

The WHO highlights that its research is only about the question of whether or not something causes cancer 語法

WHO强调，其研究只探讨某物是否致癌，

and not to what extent.

而不是致癌的程度。

But processed meat may also significantly increase the chance of suffering from diabetes,

但加工肉类也可能显著增加患糖尿病、

strokes,

中风，

and coronary heart diseases.

和冠心病的几率。

It also makes a difference what sort of life our meat lived 短語搭配

我们所吃的肉类在还是活物时经历了怎样的生活，这也有影响，

when it was still part of a living being.

当它还是一个生命体的一部分时。

It's common to feed large amounts of antibiotics to livestock in order to prevent diseases, 語法

为了预防疾病，给牲畜喂食大量抗生素是很常见的，

which can spread antibiotic resistance.

这会导致抗生素耐药性的传播。

Combined,

综合来看，

a high consumption of both red and processed meat

大量食用红肉和加工肉类

could increase your chance of premature death by up to 29%. 用詞

会使你过早死亡的几率增加高达29%。

This means if your chance of dying is 3% this year,

这意味着，如果你今年的死亡概率是3%，

it's now 4%.

那么现在就是4%。

This might not sound like a lot, 表達脈絡

这听起来可能不多，

but tiny percentages have a huge impact on societies of millions.

但微小的百分比对数以百万计的社会有巨大的影响。

They also seem harmless until they affect you.

在它们影响到你之前，它们看起来似乎是无害的。

To blame meat alone for bad health would be wrong, 語法

不过，把健康不佳完全归咎于肉类是错误的，

though.

虽然。

There is no evidence that the very essence of meat has any negative effect beyond its high fat content,

没有证据表明肉类本身的本质除了其高脂肪含量外，还有任何负面影响，

and even this point is highly contentious. 用詞

甚至这一点也是极具争议的。

Just like with many other pleasures in life,

就像生活中的许多其他乐趣一样，

sometimes too much of a good thing is harmful. 習語

有时好东西吃太多也会有害。

Most public health agencies suggest cutting meat consumption to 500 grams a week,

大多数公共卫生机构建议将肉类消费量减少到每周500克，

while studies suggest cutting down processed meat as much as possible.

而研究则建议尽量减少加工肉类的摄入。

So,

所以，

if you feast on meat no more than once or twice a week, 講解

如果你每周大吃大喝不超过一两次，

you should be good. 語氣意圖

你应该没问题。

For most people,

对于大多数人来说，

this already means a drastic change in their diets though.

这就已经意味着他们的饮食习惯发生了巨大的改变。

The average American consumes around almost 1,600 grams of meat a week.

一个普通的美国人平均每周消耗近1600克肉类。

The average German 1,100 grams a week. 語法

一个普通的德国人平均每周1100克。

And many of us eat much, 語法

而我们很多人吃得要多得多，

much more.

多得多。

If you're not really sure,

如果你不太确定，

make a small note whenever you eat meat for a week or two.

可以在一两个星期里，每次吃肉时做个小记录。

You'll be surprised how much it really is.

你会惊讶地发现，你吃的量居然有那么多。

So,

所以，

most people watching this video would benefit from cutting down on meat. 短語動詞

大多数观看这个视频的人都会从减少吃肉中受益。

Aside from health concerns, 表達脈絡

除了对健康的担忧，

there's still the fact that the meat industry is one of the largest contributors to climate change 語法

肉类工业还是导致气候变化的最大因素之一，

and has reached a scale 語法

并且其规模已经达到了这样的程度：

where it's impossible to deliver millions of tons of meat

即不可能在提供数百万吨肉类的同时

and still treat animals with dignity. 短語搭配

还能有尊严地对待动物。

We've already discussed that in detail in another video.

我们已经在另一期视频中详细讨论过这个问题。

All in all, 表達脈絡

总而言之，

in moderation, 短語搭配

适量食用，

meat is not unhealthy

肉类并不不健康，

and you don't need to become vegetarian overnight 用詞

你也不需要一夜之间变成素食主义者，

to have a real impact on your health and the planet.

就能对你的健康和地球产生实质性的影响。

But your lifestyle choices do matter for yourself and for others. 語法

但你的生活方式选择，对你自己和他人来说，确实很重要。