外媒8月3號文章：吃什麼很重要，什麼時候吃也一樣（中英對照）

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長期以來，營養學家們一直在爭論對於理想的健康狀況而言，最佳的日常飲食是什麼。但是如今一些專家認為，重要的不僅僅是吃什麼，還有什麼時候吃。

Nutrition scientists have long debated the best diet for optimal health. But now some experts believe that it』s not just what we eat that』s critical for good health, but when we eat it.

越來越多的研究表明，當飲食模式與生物鐘相匹配時，我們的身體能夠以最佳狀態運轉。長期打亂這種規律，例如吃得很晚或是在深夜吃一點零食，都可能導致體重增加以及新陳代謝問題。

A growing body of research suggests that our bodies function optimally when we align our eating patterns with our circadian rhythms, the innate 24-hour cycles that tell our bodies when to wake up, when to eat and when to fall asleep. Studies show that chronically disrupting this rhythm — by eating late meals or nibbling on midnight snacks, for example — could be a recipe for weight gain and metabolic trouble.

以這樣的結論為前提，索爾克研究所教授及人體晝夜節律研究方面專家的薩欽·潘達(Satchin Panda)在新書《節律密碼》(The Circadian Code)中提出，把每天的可進食時段控制在8-10個小時之內，即在早晨吃第一頓、傍晚吃最後一頓時，有助於提升人們的新陳代謝健康。

That is the premise of a new book, 「The Circadian Code,」 by Satchin Panda, a professor at the Salk Institute and an expert on circadian rhythms research. Dr. Panda argues that people improve their metabolic health when they eat their meals in a daily 8- to 10-hour window, taking their first bite of food in the morning and their last bite early in the evening.

這一方法也被稱為「提早限時進食法」，它源於人類的新陳代謝遵循日常節律，即我們體內的激素水平、酶以及消化系統都更傾向於在早晨和下午進食這一理念。然而很多人大約從早晨醒來一直到睡前都在吃東西。潘達博士在他的研究中發現，平均人們每天在長達15個小時或更長的時段內進食，通常是早晨起來喝一杯牛奶或咖啡，睡前再喝一杯酒、吃頓夜宵，或是一大把薯片、堅果等其他零食。

This approach, known as early time-restricted feeding, stems from the idea that human metabolism follows a daily rhythm, with our hormones, enzymes and digestive systems primed for food intake in the morning and afternoon. Many people, however, snack and graze from roughly the time they wake up until shortly before they go to bed. Dr. Panda has found in his research that the average person eats over a 15-hour or longer period each day, starting with something like milk and coffee shortly after rising and ending with a glass of wine, a late night meal or a handful of chips, nuts or some other snack shortly before bed.

潘達教授說，這種飲食模式與我們的生物節律相違背。

That pattern of eating, he says, conflicts with our biological rhythms.

科學家們早就發現人類大腦中存在一個主生物鐘，它位於下丘腦，能夠對亮光進行反饋，從而控制睡眠和清醒的周期。幾十年前，研究者們發現人體內存在大量的生物鐘，而不是僅有一個。每個器官都有一個內在的生物鐘，掌管著它的日常活動周期。

Scientists have long known that the human body has a master clock in the brain, located in the hypothalamus, that governs our sleep-wake cycles in response to bright light exposure. A couple of decades ago, researchers discovered that there is not just one clock in the body but a collection of them. Every organ has an internal clock that governs its daily cycle of activity.

白天，胰腺會增加胰島素的分泌，用以控制血糖水平，而到了晚上這一過程就會減慢。腸道也有一個生物鐘，用以管理每天酶的分泌量的起伏、營養的吸收以及廢物的排出。我們腸道內數以億計的細菌構成的菌群也以日節律運轉。這些日節律是如此根深蒂固，以至於它們被寫入了我們的基因：研究表明，在每個器官當中，成千上萬的基因都在每天大約同一時刻工作和休息。

During the day, the pancreas increases its production of the hormone insulin, which controls blood sugar levels, and then slows it down at night. The gut has a clock that regulates the daily ebb and flow of enzymes, the absorption of nutrients and the removal of waste. The communities of trillions of bacteria that comprise the microbiomes in our guts operate on a daily rhythm as well. These daily rhythms are so ingrained that they are programmed in our DNA: Studies show that in every organ, thousands of genes switch on and switch off at roughly the same time every day.

「我們在這個星球上居住了數千年，儘管很多事情發生了變化，但是仍有一件事是永恆的，那就是每天太陽都會照常升起和落下，」潘達教授說。「我們在生理和代謝上被設定好擁有以24小時為周期的節律。這些節律之所以存在，是因為就像我們的大腦每晚需要修復、重啟和恢復活力一樣，每個器官也需要有休息時間來修復和重啟。

「We』ve inhabited this planet for thousands of years, and while many things have changed, there has always been one constant: Every single day the sun rises and at night it falls,」 Dr. Panda said. 「We』re designed to have 24-hour rhythms in our physiology and metabolism. These rhythms exist because, just like our brains need to go to sleep each night to repair, reset and rejuvenate, every organ needs to have down time to repair and reset as well.」

人體內的大多數跡象都表明，白天儘早進食對我們的健康有好處，阿拉巴馬大學伯明翰分校營養科學系的副教授考特尼·彼得森(Courtney Peterson)說。大量研究顯示，血糖控制在早晨最佳，而在晚上最差。同時，我們在早晨燃燒卡路里及消化食物的效率也更高。

Most of the evidence in humans suggests that consuming the bulk of your food earlier in the day is better for your health, said Dr. Courtney Peterson, an assistant professor in the department of nutrition sciences at the University of Alabama at Birmingham. Dozens of studies demonstrate that blood sugar control is best in the morning and at its worst in the evening. We burn more calories and digest food more efficiently in the morning as well.

晚上，光照的缺乏會促使大腦分泌褪黑素，幫助我們入睡。晚上吃得太晚會給體內其他器官發出一條與其生物鐘相違背的指令，彼得森博士說。

At night, the lack of sunlight prompts the brain to release melatonin, which prepares us for sleep. Eating late in the evening sends a conflicting signal to the clocks in the rest of the body that it』s still daytime, said Dr. Peterson.

「如果你持續在一天之中沒有光照的時間段內飲食，那麼你的體內不同的生物鐘就會發生紊亂，」她說。「這就好像一個時鐘在日本所在的時區，而其他的在美國。這會給你的新陳代謝發出互相矛盾的指令，到底什麼時候加速運轉，什麼時候減速休息。」

「If you』re constantly eating at a time of day when you』re not getting bright light exposure, then the different clock systems become out of sync,」 she said. 「It』s like one clock is in the time zone of Japan and the other is in the U.S. It gives your metabolism conflicting signals about whether to rev up or rev down.」

當我們坐飛機穿過多個時區，或是開夜車以致打亂大腦內的中央生物鐘時，我們會感到疲憊，時差和大腦混沌紛至沓來。在一天中不當的時間吃東西會給涉及到消化的器官帶來類似的壓力，迫使他們在本該休息的時間繼續工作，而這可能會增加疾病的風險，加州大學歐文分校錶冠遺傳學及代謝中心的主任保羅·薩森-科西(Paolo Sassone-Corsi)說。

Most people know what happens when we disrupt the central clock in our brains by flying across multiple time zones or burning the midnight oil: Fatigue, jet lag and brain fog set in. Eating at the wrong time of day places similar strain on the organs involved in digestion, forcing them to work when they are programmed to be dormant, which can increase the risk of disease, said Paolo Sassone-Corsi, the director of the Center for Epigenetics and Metabolism at the University of California, Irvine.

「眾所周知，改變或打亂一個人正常生活的節律會增加患上多種疾病的風險，」薩森-科西博士(Dr. Sassone-Corsi)說。她最近發表了一篇有關營養、新陳代謝與生物節律之間相互影響的論文。

「It』s well known that by changing or disrupting our normal daily cycles, you increase your risk of many pathologies,」 said Dr. Sassone-Corsi, who recently published a paper on the interplay between nutrition, metabolism and circadian rhythms.

一個典型的例子就是輪班工作的人，他們約佔國家勞動力中的20%。很多人頻繁地在夜間上夜，這使得他們只能在奇怪的時間點吃飯和睡覺。夜間輪班的工作和肥胖、糖尿病、某些癌症及心臟病相關。儘管社會經濟方面的因素很可能在其中起作用，但研究表明晝夜顛倒會直接導致健康惡化。

A classic example of this is shift workers, who account for about 20 percent of the country』s work force. Many frequently work overnight shifts, forcing them to eat and sleep at odd times. Nighttime shift work is linked to obesity, diabetes, some cancers and heart disease. While socioeconomic factors are likely to play a role, studies suggest that circadian disruption can directly lead to poor health.

在一項實驗中，健康的成年人被要求連續10天推遲入睡時間並起得比平時更晚（這打破了他們的生物節律及飲食模式），科學家們發現，這導致他們血壓升高，胰島素及血糖控制能力下降。另一項研究發現，僅僅強迫人們連續熬幾天夜也會導致體重迅速增加以及胰島素敏感度降低，這些都是導向糖尿病的身體變化。

In one experiment, scientists found that assigning healthy adults to delay their bedtimes and wake up later than normal for 10 days — throwing their circadian rhythms and their eating patterns out of sync — raised their blood pressure and impaired their insulin and blood sugar control. Another study found that forcing people to stay up late just a few nights in a row resulted in quick weight gain and reduced insulin sensitivity, changes linked to diabetes.

2012年，潘達博士和他在索爾克研究所的同事將基因上完全相同的老鼠分成兩組。一組可以隨時吃到高脂肪、高糖分的食物，另一組只能在8小時的時間段內吃到相同的食物。儘管兩組老鼠攝入的卡路里總數相同，但是隨時都可以吃到東西的那組老鼠變胖、生病，而在規定時間內進食的老鼠卻沒有。

In 2012, Dr. Panda and his colleagues at the Salk Institute took genetically identical mice and split them into two groups. One had round-the-clock access to high-fat, high-sugar foods. The other ate the same foods but in an eight-hour daily window. Despite both groups consuming the same amount of calories, the mice that ate whenever they wanted got fat and sick while the mice on the time-restricted regimen did not: They were protected from obesity, fatty liver and metabolic disease.

受到這一研究的啟發，彼得森博士在一小群前驅糖尿病男性患者中間進行了一個嚴格控制變數的實驗。在研究的一個階段里，受試者連續五周在每天12小時的時段內進食。在另一階段里，他們在從每天早晨開始的6小時內進食，吃的東西都一樣。研究者們讓受試者們吃足夠多的東西以保持他們的體重不變，這樣研究者就能評估嚴格控制時間的飲食方式是否能帶來與減重無關的健康益處。

Inspired by this research, Dr. Peterson conducted a tightly controlled experiment in a small group of prediabetic men. In one phase of the study, the subjects ate their meals in a 12-hour daily window for five weeks. In the other phase, they were fed the same meals in a six-hour window beginning each morning. The researchers had the subjects eat enough food to maintain their weight so they could assess whether the time-restricted regimen had any health benefits unrelated to weight loss.

確實如此。在嚴格控制進食時間的階段內，受試者們顯現出更低的胰島素水平、更低的氧化應激程度、更少的夜間飢餓以及大大降低的血壓值。他們的收縮壓下降了大約11個點，舒張壓下降了大約10個點。

It did. On the time-restricted regimen, the men had lower insulin, reduced levels of oxidative stress, less nighttime hunger and significantly lower blood pressure. Their systolic pressure, the top number, fell by roughly 11 points, and their diastolic pressure dropped by 10 points.

「這是一個非常顯著的影響，」彼得森博士說。「這令人激動但也令人震驚。」

「It was a pretty large effect,」 Dr. Peterson said. 「It was exciting but also shocking.」

儘管研究表明白天更早進食對代謝健康有益，但這並不意味著人們可以不吃晚飯。但是，讓你的晚餐相對清淡可能是明智的。以色列的一群研究者在研究中發現，與早餐吃得少、晚餐吃得多相比，當早餐吃得多、午餐吃得適中、晚餐吃得少時，超重的成年人能減少更多的重量，並且在血糖、胰島素及與心血管疾病相關的因素上大有改善。彼得森博士說，這印證了一句古老的格言：早餐吃得像國王，午餐吃得像王子，晚餐吃得像乞丐。

While studies suggest that eating earlier in the day is optimal for metabolic health, it does not necessarily mean that you should skip dinner. It might, however, make sense to make your dinners relatively light. One group of researchers in Israel found in studies that overweight adults lost more weight and had greater improvements in blood sugar, insulin and cardiovascular risk factors when they ate a large breakfast, modest lunch and small dinner compared to the opposite: A small breakfast and a large dinner. Dr. Peterson said it confirms an age-old adage: Eat breakfast like a king, lunch like a prince and dinner like a pauper.???