Hunger claws at your grumbling belly.
饥饿感挠着你饥肠辘辘的肚子。
It tugs at your intestines, which begin to writhe, aching to be fed.
它拖拽着你的肠子，于是肠子开始蠕动，等待着被喂食。
Being hungry generates a powerful, often unpleasant physical sensation that's almost impossible to ignore.
饥饿会产生强大的、令人不悦的生理感觉，几乎让你无法忽视。
After you've reacted by gorging on your morning pancakes,
在你狼吞虎咽完早餐薄饼后，
you start to experience an opposing force, fullness, but how does your body actually know when you're full?
你开始体会到完全相反的感觉，饱足感，但是当你吃饱的时候，你的身体是如何知道的呢？
The sensation of fullness is set in motion as food moves from your mouth down your esophagus.
饱足感随着食物从你的口中进入食道中就开始出现了。
Once it hits your stomach, it gradually fills the space.
一旦食物到达胃，便逐渐填充胃的空间。
That causes the surrounding muscular wall to stretch, expanding slowly like a balloon.
这导致周边的肌肉壁开始延展，就像气球一样缓慢扩张。
A multitude of nerves wrapped intricately around the stomach wall sense the stretching.
胃壁中大量的错综复杂的神经感受到了这种扩展。
They communicate with the vagus nerve up to the brainstem and hypothalamus,
它们与位于脑干和下丘脑的迷走神经交换信息，
the main parts of the brain that control food intake.
这是大脑中的主要部分，掌管食物的摄取。
But that's just one input your brain uses to sense fullness.
但这只是大脑用来感受饱足感的其中一个来源。
After all, if you fill your stomach with water, you won't feel full for long.
毕竟，当你的胃充满水的时候，饱足感并不会持续很长时间。
Your brain also takes into account chemical messengers
你的大脑也会考虑化学因素，
in the form of hormones produced by endocrine cells throughout your digestive system.
它们以内分泌细胞产生的激素形式存在于整个消化系统中。
These respond to the presence of specific nutrients in your gut and bloodstream,
它们会对你内脏和血管中特定的营养成分产生反应，
which gradually increase as you digest your food.
当你消化食物时会逐渐加强。
As the hormones seep out, they're swept up by the blood and eventually reach the hypothalamus in the brain.
当激素溢出来时，它们会被血液冲走，并最终到达大脑中的下丘脑。
Over 20 gastrointestinal hormones are involved in moderating our appetites.
超过20种肠胃激素参与调和我们的口味。
One example is cholecystokinin, which is produced in response to food by cells in the upper small bowel.
胆囊收缩素就是其中一个例子，它是由上小肠的细胞通过食物刺激产生的。
When it reached the hypothalamus, it causes a reduction in the feeling of reward you get when you eat food.
当它到达下丘脑时，会降低你吃食物时的满足感。

When that occurs, the sense of being satiated starts to sink in and you stop eating.
当发生这种情况时，饱足感开始潜入，你也会停止进食。
Cholecystokinin also slows down the movement of food from the stomach into the intestines.
胆囊收缩素也会减缓食物从胃到肠的运行速度。
That makes your stomach stretch more over a period of time, allowing your body to register that you're filling up.
这会让你的胃持续扩展一段时间，让你的身体知道你已经饱了。
This seems to be why when you eat slowly, you actually feel fuller compared to when you consume your food at lightning speed.
这似乎解释了和当你狼吞虎咽时相比，进食速度更慢为何就会觉得更饱。
When you eat quickly, your body doesn't have time to recognize the state it's in.
当你狼吞虎咽时，你的身体缺少足够的时间来了解进食状态。
Once nutrients and gastrointestinal hormones are present in the blood, they trigger the pancreas to release insulin.
一旦血液中有了营养素和肠胃激素，它们会触发胰腺分泌胰岛素。
Insulin stimulates the body's fat cells to make another hormone called leptin.
胰岛素会刺激人体的脂肪细胞产生另一种叫做瘦素的激素。
Leptin reacts with receptors on neuron populations in the hypothalamus.
瘦素与下丘脑神经元群的受体相互作用。
The hypothalamus has two sets of neurons important for our feeling of hunger.
下丘脑有两组对饥饿感非常重要的神经元。
One set produces the sensation of hunger by making and releasing certain proteins.
一组通过制造和释放某些蛋白质来产生饥饿感。
The other set inhibits hunger through its own set of compounds.
另一组通过组内自身的复化合物抑制饥饿感。
Leptin inhibits the hypothalamus neurons that drive food intake and stimulates the neurons that suppress it.
瘦素抑制驱动食物摄入的下丘脑神经元，并刺激神经元压制它。
By this point, your body has reached peak fullness.
此时，你的身体已极度饱胀。
Through the constant exchange of information between hormones, the vagus nerve, the brainstem, and the different portions of hypothalamus,
通过在激素、迷走神经、脑干以及下丘脑的不同部分进行的持续性信息交换，
your brain gets the signal that you've eaten enough.
你的大脑收到了已经吃饱的信号。
Researchers have discovered that some foods produce more long-lasting fullness than others.
研究者发现，某些食物较其他食物而言，会产生更持久的饱足感。
For instance, boiled potatoes are ranked as some of the most hunger-satisfying foods,
例如，水煮土豆在最让人有饱足感的食物中榜上有名，
while croissants are particularly unsatisfying.
然而羊角面包带来的饱足感则令人失望。
In general, foods with more protein, fiber, and water tend to keep hunger at bay for longer.
总而言之，富含蛋白质、食物纤维和水份的食物能让饱足感延续时间更长。
But feeling full won't last forever.
但是饱足感不会永远持续。
After a few hours, your gut and brain begin their conversation again.
几小时之后，你的内脏和大脑又开始了它们的交流。
Your empty stomach produces other hormones, such as ghrelin,
空空如也的胃产生了其他激素，例如饥饿激素，
that increase the activity of the hunger-causing nerve cells in the hypothalamus.
它会加速在下丘脑发生的饥饿神经细胞活动。
Eventually, the growling beast of hunger is reawakened.
最终，饥饿这头低吼的野兽又被唤醒。
Luckily, there's a dependable antidote for that.
幸运的是，我们有一个可靠的解药。