一詞日曆：1個月不吃甜食會怎樣？竟然性情大變
2019.03.30
週六 Saturday
tolerant /'tɔlərənt/
adj. 能忍受……的
圖片來源：視覺中國
In neuroscience, food is something we call a "natural reward". In order for us to survive as a species, things like eating must be pleasurable to the brain so that these behaviours are reinforced and repeated.
在神經科學中，我們稱食物爲“自然獎勵”。爲了讓我們作爲一個物種生存下來，像吃飯這樣的事情必須讓大腦愉悅，這樣這些行爲才能得到強化和重複。
Not all foods are equally rewarding, of course. Most of us prefer sweets over sour and bitter foods because, evolutionarily, our mesolimbic pathway reinforces that sweet things provide a healthy source of carbohydrates for our bodies.
當然，並非所有的食物都有同樣的回報。我們大多數人喜歡甜食而不是酸的和苦的食物，因爲從進化上講，我們的中邊緣通路不斷加固甜食爲我們的身體提供健康碳水化合物。
Anyone who knows me also knows that I have a huge sweet tooth. My friend and fellow graduate student Andrew is equally afflicted, and living in Hershey, Pennsylvania – the "Chocolate Capital of the World" – doesn't help either of us.
認識我的人都知道我超愛吃甜食。我的研究生朋友安德魯也深受其苦，住在“巧克力世界之都”賓夕法尼亞州的好時市也沒幫上我倆什麼。
But Andrew is braver than I am. Last year, he gave up sweets for Lent.
但安德魯比我有魄力。去年，他爲了四旬齋戒了糖果。
"The first few days are a little rough," Andrew told me about his sugar-free adventure last year.“
前幾天有點難熬，”安德魯告訴我他去年的無糖嘗試。
"It almost feels like you're detoxing from drugs. I found myself eating a lot of carbs to compensate for the lack of sugar."
“感覺就像在戒毒。我發現自己吃了很多碳水化合物來彌補糖的不足。”
In short, this means that repeated access to sugar over time leads to prolonged dopamine signalling, greater excitation of the brain's reward pathways and a need for even more sugar to activate all of the midbrain dopamine receptors like before.
簡而言之，這意味着長時間內反覆接觸糖會導致多巴胺信號延長，大腦的獎勵通道更爲興奮，要像以前激活所有的中腦多巴胺受體一樣的效果需要更多的糖。
The brain becomes tolerant to sugar – and more is needed to attain the same "sugar high".
大腦對糖的耐受性越來越強，達到同樣的“糖嗨”需要更多的糖。
But after 40 days, it's clear that Andrew had overcome the worst, likely even reversing some of his altered dopamine signalling. "I remember eating my first sweet and thinking it was too sweet," he said. "I had to rebuild my tolerance."
但40天后，安德魯顯然已經克服了最糟的情況，甚至可能逆轉了他延長的多巴胺信號。”他說：“我記得我之後第一次吃甜食時，覺得太甜了。”我必須重建我的耐甜度。”
今日詞彙
tolerant /'tɔlərənt/
adj. 能忍受……的
Tolerant 這個形容詞是由動詞 tolerate 變來的。
Tolerate 的意思是“忍受”，tolerant 表示“能忍受……的”，除了 to 也能和 of 連用：
The plants are tolerant of frost.
這些植物很耐霜凍。
