2016军营大拜年伊泓远:饥饿能让大脑偏向于垃圾食品

英国经济法的第一条就规定超市手推车中食品的数量要与购物者的饥饿程度相当。

But while the danger is well known to shoppers who venture out on an empty stomach, how the problem arises in the brain has remained a mystery.

但是那些空腹就出门的购物者都知道面临的危险是什么，但却不知道饥饿会对大脑产生什么样的问题。

In a new study of hunger's effects on the mind, neuroscientists pieced together what happens in the brain that makes us buy more food when we are famished.

在一项对大脑受饥饿影响的研究中，神经科学家将大脑产生的各种影响进行了一个整体的分析，得出这样的一个结论，即我们在饥饿的时候会购买更多的食品。

The findings point to ways of overcoming the temptations of the food aisles and throw fresh light on the rise of obesity over the past 30 years.

这个研究发现让人们知道了如何去抵制食品货架的诱惑，并且对过去30年肥胖人群数量的增加的原因有了一个不一样的看法。

From a series of brain scans on volunteers, the researchers showed that a hunger hormone triggered activity in the brain that made people pay more for junk food than usual. Equipped with this knowledge, shoppers should be able to override the urge and stick to more healthy shopping, the scientists said.

通过对志愿者大脑的观察，研究人员发现饥饿激素能够刺激大脑活动，人买的垃圾食品比平常要多。对此科学家们是这样说的，购物者在得知这个发现后，应该更能克制这样的冲动，坚持健康购物。

"You should never make decisions about food when you are starving. When you go to the supermarket hungry, the food you are drawn to is high-calorie junk food," said Dr Alain Dagher, a neurologist at the Montreal Neurological Institute. "You assign way too much value to calories and so way too little to health and other things."

蒙特利尔神经学研究所的神经专家Alain Dagher博士称：“在你处于饥饿状态的时候，千万不要轻易去购买食物。空腹去逛超市时，你盯住的食物只能是高热量的垃圾食品。你过多的关注了食物的热量，忽略了健康和其他因素了。”

Dagher and his colleague Deb Tang recruited 29 volunteers for the study and, asked them to rate how much they liked various items of food, from chocolate cookies and potato crisps to apples and carrots.

Dagher和他的同事Deb Tang在这次研究中一共请用了29名志愿者，让他们对食品的渴求程度进行记录，其中食品既有有巧克力曲奇饼和薯条，也有苹果和胡萝卜。

The scientists next put the volunteers in a brain scanner and had them bid up to five dollars a time for food and other objects, such as baseball caps and T-shirts, that flashed up on a screen.

接下来，科学家们会对志愿者的大脑活动进行观测，让他们对闪现在屏幕上的食物和其他物品（例如棒球帽和T恤）进行5美元一次的出价。

After each volunteer had bid for 300 items, one bid was taken and compared with a counterbid generated at random by a computer. If the volunteer bid the most, they got to eat the food or keep the item at stake.

每次实验志愿者都得对300个物品进行出价，出的每一次价都会跟电脑随机产生的价格进行比较。如果哪种食物志愿者出价最高，那他就可以去吃这个食物或者将这个食物留到自己想吃的时候。

Each person took the test twice over two days and beforehand received either an injection of ghrelin, a hunger hormone that is released by the stomach, or a shot of saline as a control. The ghrelin jab made volunteers ravenous for one to two hours.

每个人两天里做的测试是多过两次的，并且这些人在参加测试之前都会注射一种胃饥饿素（从胃里释放出的一种饥饿激素），或者是盐水。胃饥饿素会使志愿者保持饥饿状态长达1到2小时。

Unsurprisingly, the hungry volunteers bid consistently more for food and less for inedible items than the volunteers who had the saline jab. The hungry people were willing to spend an average of $2.09 for food and $1.32 for other objects, but on saline bid only $1.82 for food and $1.58 for the inedible items.

饥饿的志愿者给食物的出价要高于非食用物品，并且出价要高于那些注射盐水的人，这一点并不让人吃惊。饥饿的人对食物的平均出价是2.09美元，非食用物品为1.32美元，但注射盐水的人对食物的出价是1.82美元，非食用物品为1.58美元。

The scientists traced the behaviour to increased activity in a brain region called the ventromedial prefrontal cortex, which is involved in motivation and reward.

科学家在研究过这些行为之后，将原因归结为大脑的腹内侧前额皮层活动影响，该区域是属于大脑的刺激和反馈活动。

"Ghrelin seems to increase the amount you are willing to pay for food through this area of the brain. We think this is why you assign greater value to the food when you are hungry," Dagher said. The research was presented at the Society for Neuroscience meeting in Washington DC.

Dagher说：“通过大脑皮层，胃饥饿素似乎增加你购买食物的数量。我们认为这也就解释了为什么人在饿了的时候更愿意去吃东西的行为。”这项研究是在华盛顿的神经科学学会进行的。

But the study found that people did not simply pay more for foods they liked. Instead, the higher bids were for the high-calorie junk foods.

但是这个研究还发现人并不会去购买更过他们喜欢的食物，反而是那些高热量的垃圾食品。

"When you are hungry you assign way too much value to calories and so way too little to health and other things," Dagher said.

Dagher说：“在你饿了的时候，你更愿意去注重食物的热量，忽略了食物的健康和其他因素。”

Dagher believes that simply being aware of the way the brain works could help people overcome the urge to buy junk food when they are hungry. "We have this intrinsic value system but we can override it with our minds," he said.

Dagher认为只要了解了大脑的活动方式，人们就可以在饥饿的时候克服购买垃圾食品的欲望，他还说：“我们虽然拥有这个内在的倾向系统，但我们却不能利用大脑去克服它带来的影响。”

The findings support evidence that shows skipping meals to lose weight can be counterproductive. "If you miss meals, you tend to gain weight because you get hungrier and eat calorically dense foods," Dagher said.

这个发现也是支持了这样一个说法，利用节食来减肥是收效甚微的。Dagher说：“如果你在节食，那你会更容易胖，因为在你饿的时候会更容易吃掉那些高热量的食物。”

"The main reason for the increase in obesity over the past 30 years is the cost of food. When you look at an item of high-calorie food, its cost is low, so you're more likely to buy it. And once you have bought it, you are more likely to consume it.

他还说：“过去30年来肥胖人群数量增加的主要原因就是食物的效用问题。在你看着高热量食物时，其效用是很低的，因此你更愿意去购买这些食物。一旦你买下了，你吃掉这些高热量食物的可能性就更大了。”

"The problem is the decision-making before you even sit down to your meal. That's where you have lost the battle," Dagher said.

“问题的关键就是在你坐下来用餐之前所作的决定。这也是你减肥之战失败的症结所在。”