喝汽水真的会让人发胖吗？

We all know that sugary, fizzy drinks are full of calories - with the equivalent of about seven teaspoons of sugar in a standard can of cola.

我们都知道甜甜的汽水全是卡路里—一罐可乐中含有相当于七茶匙的糖。

But is it only the sugar in the drink that swells our waists, or could it also be the bubbles?

但让我们腰围增长的仅仅是饮料中的糖分呢，还是说气泡也有影响？

In a recent study done last year at Birzeit University in the Palestinian territories, researchers took a group of male rats and gave them either a fizzy sugary drink, a flat sugary drink or tap water to consume.

在最近巴勒斯坦占领区的比尔泽特大学里进行了一项研究，研究者们采用了一组雄性大鼠，给它们分别喂食甜汽水，甜饮和自来水。

They found that the rats who regularly drank the gassy sugary drink put on more weight at a much faster rate than rats given either flat sugary liquids or tap water.

他们发现日常喝甜汽水的大鼠比别的大鼠以更快的速度增重，无论别的大鼠是喝甜饮还是自来水。

When they took blood samples, they found that the rats drinking fizz had much higher levels of the hunger hormone ghrelin, which could explain the weight gain.

当他们采集血样后发现喝甜汽水的大鼠体内胃饥饿素的含量更高，这就可以解释增重的现象。

It was such an interesting study that we thought we should do a similar experiment, but with a mix of human volunteers.

这项研究如此有趣以至于我们觉得应该在人类的志愿者群体里做类似的实验。

With the help of Dr James Brown from Aston University in Birmingham we recruited a group of healthy volunteers.

在伯明翰的阿斯顿大学的詹姆斯.布朗教授的帮助下，我们招募到了一批健康的志愿者。

Rather cunningly, we decided not to tell our volunteers what the experiment was really about as we didn't want that knowledge to affect the results.

令人吃惊的是，我们不打算告诉志愿者们这个实验的真实意图，因为我们不想让这影响实验结果。

So instead of telling them it was mainly about bubbles, we said it was about measuring the impact of sugary drinks on appetite - which was partly true.

所以没有告诉他们实验是测试气泡的，我们说这是为了测试甜饮对胃口的影响—这也是可以说部分是真的。

At the start of the experiment, our volunteers arrived at the lab after having gone 10 hours without food.

在实验初期，我们的志愿者们在断食十小时之后到达实验室。

They were then given identical, calorie-controlled cheese sandwiches to eat.

然后他们被发放一样的，控制好卡路里的奶酪三明治来吃。

The idea of doing this was to ensure that all our volunteers started with roughly similar levels of ghrelin in their blood.

这样做的用意是为了确保我们的志愿者一开始血液中胃饥饿素的含量基本相当。

An hour after eating their sandwich each volunteer was given one of several different soft drinks, allocated at random.

吃掉他们的三明治之后，每名志愿者会被发放几种不同的软饮中的一种，发放是随机的。

They either received a glass of a fizzy sugary drink, a glass of the same drink (but flat), a glass of fizzy water or one of flat water.

他们要么会收到一杯甜汽水，要么是同样的甜饮但是不含气，呀么是 一杯汽水，要么是一杯普通不含气的水。

Ten minutes after they had had their drink, James took a blood sample to measure the volunteers' ghrelin levels.

喝下他们的饮料十分钟后，詹姆斯会给每人采集一份血样来测试志愿者的胃饥饿素水平。

Once he'd done that, our volunteers were sent away with a food diary - so we could assess how many calories they ate in the hours following their drink.

一旦他做完之后，我们的志愿者就可以带着一份饮食记录表离开了—这样我们就可以分析他们在喝完饮料之后的几小时时间内射入的卡路里含量。

They had to come back to the lab three more times over the next couple of weeks to eat the same cheese sandwich and have bloods taken, but each time they were given a different drink.

在接下来几周内，他们必须三次返回实验室来吃同样的奶酪三明治，测血样，但每次发给他们的是不同的饮料。

This is what's known as a crossover trial - the idea being to try different things on the same person rather than just across a group.

这就被称为正交试验—在同一人身上测不同指标的理念，而不是在一群人身上测。

It means you can produce statistically significant results with fewer recruits.

这就意味着你可以用更少的志愿者测出具有统计意义的数据。

Once James had crunched the numbers we gathered our volunteers together to tell them the true purpose of our study, which was to assess the impact of not only the sugar, but the fizziness, on hunger.

在詹姆斯分析完数据后，我们把志愿者召集在一起告诉他们研究的真实意图，是为了分析除了糖分之外，气泡含量对饥饿的影响。

What James had found was that ghrelin levels were about 50% higher when people had a fizzy drink.

詹姆斯发现当人们喝甜汽水的时候胃饥饿素含量会高出50%。

So the fizzy sugary drink makes you a lot hungrier an hour later than drinking the same drink, but flat.

所以甜汽水会让你在喝完一小时后比喝同样的不含气的甜饮饿得多。

This increase in ghrelin wasn't only seen after drinking sugary fizzy drinks; there was also a slight effect when James and his team compared the impact of still with carbonated water.

胃饥饿素的上升不仅出现于喝甜饮料时，当詹姆斯和他的团队把喝含气的水的组进行对比时，也发现有轻微的影响。

We also wanted to see what effect drinking carbonated fizz had on how much food our volunteers consumed later in the day.

我们也想看看二氧化碳气泡对我们志愿者接下来一天中所持的食物又什么影响。

And that, in some ways, was even more revealing.

而这，从某些角度来说，会更有启发性。

James says: "If you group together the carbonated drinks and the non-carbonated drinks, they ate on average 120 calories more after they had had a carbonated drink than they ate after they had a non-carbonated drink, and that's a really significant finding."

詹姆斯说：“如果你把喝二氧化碳和不喝二氧化碳饮料的人放在一起，他们在喝了二氧化碳饮料之后比喝不含二氧化碳时平均多摄入120卡路里，这真是个惊人的发现。”

So, on top of the 140 calories in the fizzy drink, it seems they ate another 120 calories later in the day as a direct result of the extra ghrelin that was produced by having had a drink with fizz in it.

所以，在射入汽水本身的140卡路里之外，他们在那一天接下来的时间里还会因为喝了汽水胃饥饿素上升而多摄入120卡路里的能量。

So is it OK to drink flat, sugary drinks?

那么喝不含气的甜饮是不是就可以了呢？

Unfortunately not.

恐怕也不行。

According to James: "The take home message from this is sadly and boringly that the healthiest option is probably still water."

根据詹姆斯所说：“这项研究传达出的最后信息非常令人沮丧和无奈，最健康的选择可能还是水。”

In terms of scientific research this is early days, but it provides another good reason why people should steer clear of sweet fizzy drinks.

从科学研究角度来看，这还只是早期研究，但它也警醒了人们喝甜汽水时要小心了哦。

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