Why Does My Body Want to Snack?

楊大群

Sometimes a snack quiets your growling stomach. But sometimes you just feel like munching， even though you're not really hungry. French researchers recently found that this second type of snack attack is harder on your waistline.

That's because when you eat without being hungry， blood sugar and insulin work differently than when you are hungry.

First， let's see what happens when you're hungry. Low blood sugar can trigger that hungry feeling. When you eat， your blood sugar rises， satisfying your hunger and prompting your pancreas to secrete insulin. Insulin's job is to transport sugar from the bloodstream into your body cells. Hours later， after insulin has moved enough sugar into the cells and leveled off， your blood sugar dips and you feel hungry again.

But let's say you snack before you feel hungry again. What happens to your blood sugar then？ The French study found that if people snacked without being hungry， their blood sugar stayed the same as if they hadn't snacked at all. Why？ Since the pancreas is still secreting insulin to transport blood sugar from the previous meal， it's easily stimulated to secrete a little more insulin.

People's insulin levels rose， but their blood sugar stayed the same. So， they got hungry at about their usual time， and ate just as much as when they didn't snack.

If you're like the folks in the study， snacking when you're hungry is okay. But when you're not hungry， snacking probably won't satisfy you or make you eat less later. Instead， it'll prompt you to loosen that belt a bit.

有時，吃點零食能讓你的肚子不再咕咕叫。但有些時候，你只是想要吃點東西，盡管你并不餓。法國研究人員最近發(fā)現(xiàn)，第二種情況很容易讓你發(fā)胖。

這是因為當(dāng)你不餓的狀態(tài)下吃東西時，血糖和胰島素的變化與你饑餓的時候是不同的。

首先，讓我們看看當(dāng)你饑餓時的情況。這時，低血糖會讓你產(chǎn)生饑餓的感覺。在你吃東西的時候，你的血糖會上升，消除你的饑餓感并促使胰臟分泌胰島素。胰島素的作用是把血液中的糖分運(yùn)送到你的體細(xì)胞中。幾小時后，當(dāng)胰島素把足夠多的糖分送入細(xì)胞內(nèi)并趨于穩(wěn)定時，你的血糖量就會降下來，然后你又會開始感到饑餓。

讓我們再來說一說當(dāng)你不餓時吃零食的情況吧。你的血糖會怎樣變化呢？法國研究表明，如果人們在不餓的情況下吃零食，他們的血糖會保持不變，就像自己從沒吃過零食一樣。為什么會這樣呢？這是由于胰臟仍在分泌胰島素來輸送上一頓飯中的血糖，這時候吃零食很容易刺激胰臟分泌更多的胰島素。

人體的胰島素含量會上升，但是血糖濃度卻保持不變。因此，人們?nèi)匀粫谄匠３燥埖臅r間感到饑餓，飯量與他們不吃零食時一樣多。

如果你和研究里的人一樣，在餓的時候才吃零食，那是可以的。但如果你不餓，吃零食可能不會給你飽足感或者讓你隨后少吃點。相反，它會讓你松松褲帶，吃得更多。