为什么我们喜欢吃垃圾食品?

Many people love their ice cream, pizza, french fries, candy despite knowing that these are unhealthy. What is it about those foods that give them such mass appeal?

尽管很多人都知道像冰激凌、披萨、炸薯条、糖果等食品不健康，但是人们还是喜欢吃。为什么这类食品会有如此之大的吸引力呢？

From an evolutionary perspective, it feels reasonable to be confused about why humans have strong desires for as unhealthy of a behavior as eating high-calorie and sugar-heavy foods.

从进化角度来讲，关于为啥人类对高热量高糖食物有着强烈的渴望人们表示很困惑，但似乎又情有可原。

They're bad for hearts, bad for pancreases, bad for physiques. But they taste so good.

高糖高热量食物对心脏、胰腺、体型来说都不好，但它们味道很好。

One answer is found in a careful examination of our evolutionary history.

在仔细检查我们的进化史后，答案找到了。

It's true that an unhealthy behavior will in general may get weeded out across time, because the members of a species drawn to that behavior will not live as long and reproduce as much as the healthier ones.

的确，随着时间的流逝，不健康的行为一般都会被淘汰，因为喜欢这种行为的物种成员与喜欢健康行为的物种相比，他们不是活不久，就是繁殖的太少。

But at one point, a high calorie meal was crucial for human success.

但有一点，高热量食物对人类的成功至关重要。

Early in human history, human beings had to fight for food, kill animals with rudimentary tools, give birth without anesthetic to maintain the population, and be under several high-stress situations.

在人类历史早期，人类必须为食物而战，比如使用最基本的工具狩猎，在没有麻醉剂的情况下生育来繁衍后代，以及处于高压力环境中等等。

Some scientists think that eating meat (and thus taking in the high amount of calories) helped humans have the extra energy to support their large brains and its functions.

一些科学家认为吃肉（由此可摄入大量热量）能为人类提供源源不断的能量，由此来支撑当时人类较大的大脑及其运作。

While there are many different ideas about why people still crave these foods, one theory is that it's an evolutionary inheritance of those days.

关于为什么现在人类对于这些食物仍有较高的热情，很多人仍持有不同的观点，其中一个就是从历史进化遗传而来。

High-calorie eating feels good to us, even though for the mass of people it's no longer necessary, and in fact, dangerous.

尽管对于多数人来说高热量食物不再是必需品，实际上它们也是危险品，但对于它的美味，我们依旧还是不能罢休。