通过咀嚼消耗的能量超乎想象(上)

This is Scientific American's 60-second Science, I'm Christopher Intagliata.

这里是科学美国人——60秒科学系列，我是克里斯托弗·因塔利亚塔。

When paleoanthropologists eat lunch with biomechanists...well, let's just say the small talk can get pretty technical.

当古人类学家与生物力学家共进午餐时……嗯，有时闲聊会变得专业。

Some of us would have cooked potatoes and other people would bring raw salads, they would just spend longer time chewing that food.

有些人会吃煮熟的土豆，有些人会吃生沙拉，这会让他们花更长时间来咀嚼食物。

This got us thinking about not just the temporal amount of time it takes to get through your food, but are they expending more energy than those who are eating cooked food.

这让我们思考的不仅仅是吃完食物所花费的时间，还包括吃生食的人是否比吃熟食的人消耗更多的能量。

Adam Van Casteren of the University of Manchester says, luckily, there's a machine to measure that.

曼彻斯特大学的亚当·范·卡斯特伦表示，幸运的是，有一台可以测量的机器。

It's a clear chamber you slip over your head -- looks like an astronaut's helmet.

这是一个可以带到头上的透明罩子——看起来像宇航员的头盔。

And it measures the oxygen you breathe in, versus the carbon dioxide you breathe out--a proxy for how much energy you're burning.

它可以测量吸入的氧气和呼出的二氧化碳--计算燃烧了多少能量。

Van Casteren and his colleagues got 21 volunteers to sit in that apparatus for 45 minutes, just to get a baseline on their metabolism.

范·卡斯特伦和他的同事首先要求21名志愿者带着设备静坐45分钟，目的是为了测出他们的新陈代谢基准值。

Then, they gave them flavorless gum to chew on, for 15 minutes at a time.

然后，让他们咀嚼无味的口香糖，每次15分钟。

If you ever have to chew something for 15 minutes it's much longer than you think.

如果你不得不嚼某样东西15 分钟，那可比你想的时间要长得多。

And sometimes you have to remind people "keep chewing!"

有时我们不得不提醒志愿者“继续咀嚼!”

And boring is the key point here, I mean, like if you've chewed gum for way too long and it's lost its flavor and it's just this thing--that's what the participants were chewing.

“这里的关键是会无聊——口香糖嚼太久了，会失去味道，就是这个东西--这就是实验参与者咀嚼的东西。”

Co-author Amanda Henry of Leiden University in the Netherlands explained that, rather than cooked potatoes and raw salads -- they needed something with no taste or smell.

荷兰莱顿大学的合著者阿曼达·亨利解释说，参与者需要咀嚼没有味道或气味的食物，而非煮熟的土豆和生沙拉。

Because anything appetizing would set off a chain of digestive reactions.

因为任何开胃的东西都会引发一连串的消化反应。

Saliva and digestive juices would start flowing and that activity would swamp the metabolic measurements related to chewing.

唾液和消化液会开始流动, 这种活动会淹没与咀嚼相关的代谢测量。

And those measurements were significant -- turns out chewing a soft gum boosted the volunteers' metabolic rates by 10 percent above baseline.

这些测量值很重要--结果表明，咀嚼较软的口香糖可使志愿者的新陈代谢率比基准值高出10%。

A stiffer gum revved up metabolic rate by 15 percent.

较硬的口香糖使新陈代谢率提高了15%。