Why some days all you want to do is snack?
为什么有时明明不饿，却总想吃东西？
英文外刊
Have you ever wondered why some days all you want to do is snack?
你是否曾经想过这样一个问题：为什么有时候就想不停地吃东西？
Under normal circumstances, we feel hungry when we have burnt up the food we have eaten as energy and our blood sugar and insulin levels begin to drop. Ghrelin, a hormone connected to appetite, then communicates this to the brain, which is how we feel the need to eat.
在正常情况下，当身体消耗完为我们提供能量的食物，血糖和胰岛素水平开始下降时，我们便会感到饥饿。然后，胃饥饿素（一种与食欲有关的激素）便会将这一信息传递给大脑，这样我们就会觉得需要进食了。
But all sorts of things can interfere with this process.
但是各种各样的事情都会对这一过程造成干扰。
1 When you are tired
1、当你感到疲惫的时候
According to a 2011 study by researchers at Columbia University in the US, those who are sleep-deprived eat almost 300 calories a day more than those who get enough sleep.
据美国哥伦比亚大学2011年的一项研究显示，那些睡眠不足的人每天摄入的热量比睡眠充足的人平均多出了近300卡路里。
This is because levels of the hormone ghrelin, which tells the brain we need to eat, increase when we don’t get enough sleep.
这是因为当我们缺乏睡眠时，胃饥饿素的水平会有所上升，从而会告诉我们的大脑要吃更多的东西。
The Columbia researchers noted that the women who didn’t get enough sleep took in more fat rising by around 30g on sleep-deprived days — four times as much as the average increase for men.
哥伦比亚大学的研究人员指出，睡眠不足的女性摄入的脂肪更多，她们在睡眠不足的日子里脂肪摄入量增加了约30克，是男性平均增加量的四倍。
2 Troubled times
2、身处困境
In a 2013 study, people who were primed to expect “tough times ahead” ate more food than people who listened to neutral messages.
在2013年的一项研究中，那些得知不久之后将会身处“困境”的人会比那些听到中性信息的人吃得更多。
It’s thought that hearing about troubled times causes a survival instinct to kick in, leading to cravings for high-calorie snacks such as chocolate.
人们一旦得知即将身处困境，便会激发一种生存本能，从而会增加对巧克力等高热量零食的渴望。
3 ‘Naughty’ food cravings
3、“不守规矩”的饮食冲动
Tempted by that extra biscuit? Then just enjoy it — as researchers have found that when you feel guilty about a pleasurable experience, the guilt itself becomes pleasurable, so encouraging you to do it more.
还想再吃一块饼干？那就吃掉它吧——研究人员发现，当你为一次愉快的经历感到内疚时，内疚本身就会带来快感，进而促使你再次去做这件事。
“If we consider something a naughty pleasure, it can psychologically drive the appetite and the guilt may make you want to eat more,” says Cary Cooper, at the University of Lancaster.
兰开斯特大学的卡里·库珀说：“如果我们认为某件事会带来不守规矩的快感，那么它会在心理上促进食欲，这种负罪感会让你想吃更多。”
The appetite center of the brain also lies very close to the area governing mood — the limbic system — which is why changes in the way we feel may affect appetite.
大脑中的食欲控制区域与情绪控制区域非常接近（即边缘系统），这就是为什么我们的情绪变化会影响食欲的原因。
4 Mobiles’ blue light
4、手机蓝光
The bright blue light emitted by devices such as smartphones and tablets may give an unwelcome boost to your appetite. Research this year found that your appetite continued to increase when you are exposed to the light.
智能手机和平板电脑等电子设备发出的明亮蓝光可能会促进食欲。今年的一项研究发现，暴露在蓝光下会促使食欲的持续增加。
It also altered people’s metabolism, as blood tests showed that the blue-light subjects had higher insulin and glucose levels. One possible explanation is that bright blue light at night confuses our body clock, which has a role in controlling when we feel the need to eat.
蓝光还会调节人们的新陈代谢，据一项血液测试显示，蓝光受试者的胰岛素和血糖水平更高。一种可能的解释是，夜间明亮的蓝光会扰乱我们的生物钟，而生物钟在控制我们何时进食方面发挥着作用。
重点词汇：
appetite [ˈæpɪtaɪt] n. 食欲；嗜好
interfere with 干扰；干涉；妨碍
metabolism [məˈtæbəlɪzəm] n. 新陈代谢
confuse [kənˈfjuːz] vt. 使混乱；使困惑
