TED演讲 | 为什么你总是饿，吃不饱？

人生似乎就是在不断地饥饿和吃饭饭而周而复始的，是时候搞清楚“一顿不吃饿得慌”背后的成因啦。节食失败的同志有福啦。

中英对照演讲稿

Hunger claws at your grumbling belly. 

饥饿感正在你的腹中翻腾。 

It tugs at your intestines, which begin to writhe, aching to be fed. 

它撕扯着肠子开始扭动，渴望着食物。 

Being hungry generates a powerful, often unpleasant physical sensation that's almost impossible to ignore. 

饥饿会产生一种强烈的身体不适感，让人根本无法置之不理。 

After you've reacted by gorging on your morning pancakes, 

消化完早上吃的煎饼后，

you start to experience an opposing force, fullness, 

你就会体验到相反的感觉——饱腹感， 

but how does your body actually know when you'r full?

但是你的身体怎么知道你饱了？ 

The sensation of fullness is set in motion as food moves from your mouth down your esophagus.

当食物从嘴下咽进入食道，饱腹感就开始产生了。

Once it hits your stomach, it gradually fills the space.

食物一旦进入胃逐渐填满胃内空间。

That causes the surrounding muscular wall to stretch, expanding slowly like a balloon.

胃壁就如同气球一样，开始慢慢膨胀。

A multitude of nerves, wrapped intricately around the stomach wall, sense the stretching.

胃壁上的神经能感受到胃壁的扩张。 

They communicate with the vagus nerve, up to the brain stem and hypothalamus,

这些神经同迷走神经相连，到达脑干和下丘脑，

the main parts of the brain that control food intake.

即大脑中控制食物摄入量的部分。

But that's just one input your brain uses to sense fullness.

不过这还只是饱腹感其中的一项。 

After all, if you fill your stomach with water, you won't feel full for long.

毕竟 如果你只是喝水来灌满你的胃，也不会长时间感到饱腹的。 

Your brain also takes into account chemical messengers in the form of hormones produced by endocrine cells throughout your digestive systems.

大脑还要听取化学信使的报告，它们是由消化系统内分泌的细胞分泌的激素 。

These respond to the presence of specific nutrients in your gut and blood stream which gradually increase as you digest your food.

这些响应于肠道和血液的特定营养素，会随着消化食物逐渐增加。

As the hormones seep out, they're swept out by the blood and eventually reach the hypothalamus in the brain.

细胞分泌激素后进入到血液中，最后随血流到下丘脑中。 

Over 20 gastrointestinal hormones are involved in moderating our appetites.

超过20种的激素参与了食欲调节的过程 。

One example is cholecystokinin which is produced in response to food by cells in upper small bowel.

其中一个例子就是肠促胰酶肽，它是上肠细胞和食物反应后产生的。 

When it reaches the hypothalamus,

这种激素到达下丘脑之后，

it causes reduction in the feeling of reward you get when you eat food.

就会减少人在进食时获得的奖励感。 

When that occurs, the sense of being satiated starts to sink in and you stop eating.

这过程一旦开始，满足感就会下降，人也会停止进食。 

Cholosystokinin also slows down the movement of food from the stomach into the intestines.

肠促胰肽酶还会减慢食物从胃部到肠道的运动。 

That makes your stomach stretches more over a period of time,

让你的胃在一段时间内扩张得更大，

allowing your body to register that you're filling up.

让身体知道已经吃下这么多食物了。 

This seems why when you eat slowly you actually feel fuller compared to when you consume your food at lightning speed.

这就是为什么吃慢时比吃快时更容易感到饱的原因。

When you eat quickly, your body doesn't have time to recognize the state it's in.

吃快的时候，你的身体还来不及搞清楚状况。 

Once nutrients and gastrointestinal hormones are present in the blood,

血液中一旦出现了营养物质与肠胃激素，

they trigger the pancreas to release insulin.

就会促发胰腺释放出胰岛素。 

Insulin stimulate the body's fat cells to make another hormone called leptin.

胰岛素会刺激身体的脂肪细胞生成瘦素。 

Leptin reacts with receptors on neuron populations in the hypothalamus.

瘦素会与下丘脑的神经元群受体反应 。

The hypothalamus has two sets of neurons important for our feeling of hunger.

下丘脑有两套对于饥饿感而言相当重要的神经元。 

One set produces the sensation of hunger by making and releasing certain proteins.

其中一套通过生成和释放特定的蛋白质制造饥饿感。 

The other set inhibits hunger through its own set of compounds.

另一套则通过另一套化合物来抑制饥饿感。 

Leptin inhibits the hypothalamus neurons that drive food intake and stimulates the neurons that suppress it.

瘦素会抑制下丘脑中控制食物摄入的神经元，并刺激抑制食物摄入的神经元。

By this point, your body has reached peak fullness through the constant exchange of information between hormones,

这时通过不同部位间的激素交换，你的身体就达到了饱腹感的顶点， 

the vagus nerve, the brain stem and the different portions of hypothalamus,

通过不同部位间的激素交换，比如迷走神经、脑干、下丘脑的不同部位，

you brain gets the signal that your brain has eaten enough. 

大脑就会接收到已经吃饱的信号。 

Researchers have discovered that some foods produce more long-lasting fullness than others.

调查人员发现，某些食物会比其他食物产生更久的饱腹感。 

For instance, boiled potatoes are ranked as some of the most hunger-satisfying foods.

比如煮土豆，位于最能形成饱腹感的食物之列。 

While croissants are particularly unsatisfying.

而羊角面包则是最无法形成饱腹感的食物。 

In general, foods with moe protein, fiber and water tend to keep hunger at bay for longer.

通常蛋白质、纤维素和水分含量高的食物能更长时间驱除饥饿感。 

But feeling full won't last forever.

然而饱腹感并不会维持很久。 

After a few hours, your gut and brain begin their conversation again.

几个小时后，身体器官和大脑又会开始对话。 

Your empty stomach produces other hormones, such as ghrelin,

空腹又会产生其他的激素，例如饥饿激素 ，

and increase the the activity of hunger-causing nerve in the hypothalamus.

它会增加下丘脑内引起饥饿感的神经元的活性。 

Eventually, the growling beastt of hunger is reawakened.

咆哮的饥饿之兽最终觉醒。 

Lucklily, there's a dependable antidote for that.

幸运的是，还有可以对付它的可靠的解药。