早餐富贵晚饭贫，事实是否真如此？

Along with old classics like ‘carrots give you night vision’ and ‘Santa doesn’t bring toys to misbehaving children’, one of the most well-worn phrases in the arsenal of tired parents everywhere is that breakfast is the most important meal of the day. Many of us grow up believing that skipping breakfast is a dietary travesty – even if only two thirds of adults in the UK eat breakfast regularly, according to the Association of UK Dieticians (BDA), and around three-quarters of Americans.

在“胡萝卜让你在晚上能看得清”，“圣诞老人不会给不乖的小孩玩具”这样的老生常谈中，全世界头疼的家长们最常用的法宝之一就是：早餐是一天里面最重要的一顿饭。我们大都从小就相信不吃早餐就是饮食紊乱，而英国营养学家协会表示，在美国有四分之三的成年人有规律吃早餐，英国只有三分之二。

The clue for why breakfast is supposed to be important is in its name: we’re advised to eat it to break our overnight fast.

早餐这个名称本身就体现了其重要性：我们需要用早餐来打破整晚未进食的状态。

“The body uses a lot of energy stores for growth and repair through the night,” explains dietician Sarah Elder. “Eating a balanced breakfast helps to up our energy, as well as protein and calcium used throughout the night.”

营养学家Sarah Elder解释道：“身体中大部分的能量储存用于夜间的生长和修复，吃早餐能帮助我们补充在夜间消耗的能量、蛋白质和钙。”

But there’s widespread disagreement over whether breakfast should keep its top spot in the hierarchy of meals. As well as the rising popularity of fasting diets, there have been concerns around the sugar content of cereal and the food industry’s involvement in pro-breakfast research – and even one claim from an academic that breakfast is “dangerous”.

但是就早餐是否应该保持三餐中的最高地位，很多人持反对意见。节食越来越流行的同时，还有对谷物含糖量的关切以及对食品行业参与支持早餐研究的动机怀疑。甚至有学者声称早餐是“危险的”。

So what’s the reality? Is breakfast a necessary start to the day… or a marketing ploy by cereal companies?

真相到底是什么？早餐到底是一天的正确打开方式，还是只是麦片公司的营销策略？

Weighty decision

重大决定

The most researched aspect of breakfast (and breakfast-skipping) has been its links to obesity. Scientists have different theories as to why there’s a relationship between the two.  

研究吃或不吃早餐最常见的角度是其与肥胖之间的关系。科学家对二者之间存在联系的原因理论各异。

In one US study that analysed the health data of 50,000 people over seven years, researchers found that those who made breakfast the largest meal of the day were more likely to have a lower body mass index (BMI) than those who ate a large lunch or dinner. The researchers argued that breakfast helps increase satiety, reduce daily calorie intake, improve the quality of our diet – since breakfast foods are often higher in fibre and nutrients – and improve insulin sensitivity at subsequent meals, which can be a risk for diabetes.

美国一项研究分析了50000人超过七年的健康数据，研究者发现，相对于午餐或者晚餐吃得很多的人，把早餐做成最丰盛的一餐的人更可能会体重更轻。研究者认为早餐容易提升饱腹感从而减少日常卡路里摄入量；而且因为富含纤维和维生素，早餐能提升饮食的质量；还能为后续用餐提高胰岛素的敏感度，降低糖尿病风险。

But as with any study of this kind, it was unclear if that was the cause – or if breakfast-skippers were just more likely to be overweight to begin with.

但是无论哪个在这方面的研究都无法证明，早餐，就是让人体重减轻的原因。要是不吃早餐的人在本来就是易胖体质呢？

To find out, researchers designed a study in which 52 obese women took part in a 12-week weight loss programme. All had the same number of calories over the day, but half had breakfast, while the other half did not.

为了寻找答案，研究者设计了一个由52名肥胖女性参与，为期12周的减肥计划。所有人每天的卡路里摄入量相同，但是一半人吃早餐，另一半人不吃。

What they found was that it wasn’t breakfast itself that caused the participants to lose weight: it was changing their normal routine. The women who said before the study that they usually ate breakfast lost 8.9kg when they stopped having breakfast, compared to 6.2kg in the breakfast group. Meanwhile, those who usually skipped breakfast lost 7.7kg when they started eating it – and 6kg when they continued to skip it.

他们发现，造成参与者体重减少的原因不是早餐本身，而是她们饮食习惯的改变。那些在实验前有吃早餐习惯的人不吃早餐后减掉了8.9kg，而实验前后都吃早餐的人平均减轻了6.2kg。与此同时，实验前本来不吃早餐而现在开始吃的人减掉了7.7kg，而实验前后都不吃早餐的人减掉了6kg。

If breakfast alone isn’t a guarantee of weight loss, why is there a link between obesity and skipping breakfast?

如果早餐本身不能保证体重减轻，那为什么肥胖还会和不吃早餐有联系？

Alexandra Johnstone, professor of appetite research at the University of Aberdeen, argues that it may simply be because breakfast-skippers have been found to be less knowledgeable about nutrition and health.

亚伯丁大学食欲研究教授Alexandra Johnstone指出，这可能仅仅是因为不吃早餐的人在营养学和保健方面获知更少。

“There are a lot of studies on the relationship between breakfast eating and possible health outcomes, but this may be because those who eat breakfast choose to habitually have health-enhancing behaviours such as not smoking and regular exercise,” she says.

她说，“对吃早餐与其对健康可能造成的影响人们做了很多研究，但是可能是因为吃早餐的人更习惯坚持不吸烟并且定期锻炼这种增进健康的行为。”

A 2016 review of 10 studies looking into the relationship between breakfast and weight management concluded there is “limited evidence” supporting or refuting the argument that breakfast influences weight or food intake, and more evidence is required before breakfast recommendations can be used to help prevent obesity.

2016年，一个对十项关于早餐与体重控制之间关系研究的评论总结，只有“有限的证据”支持或反驳早餐影响体重或者食物摄入的观点。那么如果想把建议吃早餐应用于帮助抵御肥胖症，我们需要更多的证据。

Feast or fast?

吃，还是不吃？

Intermittent fasting, which involves fasting overnight and into the next day, is gaining ground among those looking to lose or maintain their weight or improve their health.  

前一天晚上直到第二天都不吃饭的间歇性节食，获得了想要减轻或维持体重、提升健康水平的人的支持。

One pilot study published in 2018, for example, found that intermittent fasting improves blood sugar control and insulin sensitivity and lowers blood pressure. Eight men with pre-diabetes were assigned one of two eating schedules: either eating all their calories between 9:00 and 15:00, or eating the same number of calories over 12 hours. The results for the 9:00-15:00 group were found to be on par with medicine that lowers blood pressure, according to Courtney Peterson, the study’s author and assistant professor of nutrition sciences at the University of Alabama at Birmingham.

2018年出版的一项初步研究发现，间歇性节食可以更好地控制血糖、提高胰岛素敏感度并且降低血压。据这项研究的作者、阿拉巴马大学营养学副教授Courtney Peterson实验：把八个患有前驱糖尿病的男性患者分成两组，分别使用不同的饮食时刻表。一组在9：00到15:00的时间里完成所有的卡路里摄入量，另一组在在超12个小时内摄入相同卡路里。结果显示前者降低血压的效果与药物作用相同。

Still, the study’s small size means more research is needed on its possible long-term benefits.

当然，这样小规模的研究意味着我们需要更多的研究来研究证明其长久裨益。

If skipping breakfast (and other food outside of a restricted time slot) could potentially be good for you, does that mean breakfast could be bad for you? One academic has said so, arguing that breakfast is ‘dangerous’: eating early in the day causes our cortisol to peak more than it does later on. This causes the body to become resistant to insulin over time and can lead to type 2 diabetes.

如果不吃早饭（或者不在规定的时刻表中的任何一餐）可能对你有好处，这是否意味着早饭对你是有害的？一位学者的确这样认为，争论说早餐是“危险的”：早上吃饭会使体内的皮质醇出现相比起后续阶段更高的峰值。随着时间累积，这会使身体排斥胰岛素还会导致2型糖尿病。

But Fredrik Karpe, professor of metabolic medicine at Oxford Centre for Diabetes, Endocrinology and Metabolism, argues this isn’t the case. Instead, higher levels of cortisol in the morning are just part of our body’s natural rhythm.

但是牛津糖尿病、内分泌和新陈代谢中心的新陈代谢药学教授Fredrik Karpe认为并非如此。相反，皮质醇在早上含量更高只是我们身体的一种自然节律。

Not only that, but breakfast is key to jumpstarting our metabolism, he says. “In order for other tissues to respond well to food intake, you need an initial trigger involving carbs responding to insulin. Breakfast is critical for this to happen,” Karpe says.

他说，不仅如此，早餐还是启动我们新陈代谢的关键。“为了让其他组织对食物摄入做出良好反应，你需要像碳水化合物这样的原始触发器对胰岛素作出反应。而早餐是促使这个环节发生的关键。”

A randomised control trial published last year involving 18 people with, and 18 people without, diabetes found that skipping breakfast disrupted the circadian rhythms of both groups and led to larger spikes in blood glucose levels after eating. Eating breakfast, the researchers conclude, is essential for keeping our body clock running on time.

一项由18名患糖尿病和十八名不患糖尿病的人组成对照实验发现，不吃早餐都会破坏两组对象的生理节律，而且会造成进食后血糖含量的更大幅升高。研究者总结，吃早饭对保持生物钟正常运行是很重要的。

Peterson says those who skip breakfast can be divided into those who either skip breakfast and eat dinner at a normal time – getting the benefits of intermittent fasting, if not breakfast – or those who skip breakfast and eat dinner late.

Peterson说那些不吃早饭的人可以被分成两类。一类不吃早饭但是正常吃晚饭，这类人不是从早餐中，而是从间歇性节食中获益。另一类人不吃早饭晚饭也吃得晚。

“For those who eat dinner later, their risk of obesity, diabetes and cardiovascular disease goes through the roof. While it seems breakfast is the most important meal of the day, it might actually be dinner,” she says.

Peterson说“对于第二类人来说，他们罹患肥胖症、糖尿病和心血管疾病的风险飞涨。这意味着相对于早餐，晚餐可能是最重要的一餐。”

“Our blood sugar control is best early in the day. When we eat dinner late, that’s when we’re most vulnerable because our blood sugar is worst. There’s more research to do, but I’m confident you shouldn’t skip breakfast and have dinner late.”  

“早上是我们血糖控制最好的时间。过晚进食正好赶上我们最脆弱的时候因为那时候血糖状态最差。虽然需要更多的研究，但我确定你不应该不吃早餐又晚饭吃得很晚。”

She says we should think of our circadian rhythm as an orchestra.

她说我们应该把我们的生理节律想象成一个合唱团。

“There are two parts of our circadian clock. There’s the master clock in the brain, which we should think of as analogous to a conductor of an orchestra, and the other half is in every organ, which has a separate clock,” she says.

“生物钟分为两部分。我们可以把位于大脑中的主生物钟看作是合唱团的指挥，而其他的局部生物钟位于各个器官。”Peterson说道。

And that ‘orchestra’ is set by two outside factors: bright light exposure and our eating schedule.

而且这个“合唱团”由两个外界因素组成：光照和我们的饮食时刻表。

“If you’re eating when you’re not getting bright light exposure, the clocks that control metabolism are in different time zones, creating conflicting signals as to whether to rev up or down.”

“如果你吃饭时却没有接受足够光照，那控制新陈代谢的生物钟们就不再同一时区，造成刺激代谢加快或者减慢的信号紊乱。”

It’s like two halves of an orchestra playing different songs, Peterson explains, and this is why eating late impairs blood sugar and blood pressure levels.

Peterson解释说，就好像合唱团的两个声部在唱不一样的歌，所以过晚进食会对血糖和血压有害。

Researchers from the University of Surrey and University of Aberdeen are halfway through research looking into the mechanisms behind how the time we eat influences body weight. Early findings suggest that a bigger breakfast is beneficial to weight control.

来自萨里大学和阿伯丁大学的研究者正在进行探索进食时间影响体重背后的机制。早期研究结果表明早餐吃的多一点对体重控制有好处。

Health food

健康的食物

Breakfast has been found to affect more than just weight. Skipping breakfast has been associated with a 27% increased risk of heart disease, a 21% higher risk of type 2 diabetes in men, and a 20% higher risk of type 2 diabetes in women.

研究发现早餐不只对体重有影响。不吃早餐会增加27%患糖尿病风险，21%男性患2型糖尿病几率以及20%女性患2型糖尿病几率。

One reason may be breakfast’s nutritional value – partly because cereal is fortified with vitamins. In one study on the breakfast habits of 1,600 young people in the UK, researchers found that the fibre and micronutrient intake, including of folate, vitamin C , iron and calcium, was better in those who had breakfast regularly. There have been similar findings in Australia, Brazil, Canada and the US.

其中一个原因可能是早餐的营养价值——一定程度上是因为谷物富含维生素。在一项调查1600民英国年轻人的早餐习惯的研究中，研究者发现，有规律吃早餐的的人叶酸、维C、铁和钙等微量元素的摄入量更大。他们还在澳大利亚、巴西、加拿大和美国有类似的发现。

Breakfast is also associated with improved brain function, including concentration and language. A review of 54 studies found that eating breakfast can improve memory, though the effects on other brain functions were inconclusive. However, one of the review’s researchers, Mary Beth Spitznagel, says there is “reasonable” evidence breakfast does improve concentration – there just needs to be more research.

早餐还与提高包括注意力集中、语言能力的大脑机能有关。一项对54个研究的评论发现，吃早餐可以提高记忆力，虽然对其他脑部功能的影响是不确定的。然而这项回顾的研究者Mary Beth Spitznagel表示存在“不少”证据表明早餐可以提高注意力，只是需要更多的研究证明。

“Looking at studies that tested concentration, the number of studies showing a benefit was exactly the same as the number that found no benefit,” she says.

“在研究注意力的实验中，证明早餐有益和无益的数量相同。”她说。

“And no studies found that eating breakfast was bad for concentration.”

“而且没有实验证明早餐对注意力有害。”

What’s most important, some argue, is what we eat for breakfast.

有些人认为最重要的是我们早餐吃什么。

High-protein breakfasts have been found particularly effective in reducing food cravings and consumption later in the day, according to research by the Australian Commonwealth Scientific and Industrial Research Organisation.

根据澳大利亚联邦科学和工业研究组织的研究，吃完高蛋白的早餐对降低进食欲望和食用量都有显著的作用。

While cereal remains a firm favourite among breakfast consumers in the UK and US, a recent Which? investigation into the sugar content of ‘adult’ breakfast cereals found that some cereals contain more than three quarters of the recommended daily amount of free sugars in each portion, and sugar was the second or third highest ingredient in seven out of 10 flaked cereals.

英美两国，麦片是很多人早餐的不二选择，但近日一项Which？的调查发现每一份建议日常食用量的麦片中有四分之三是游离糖，并且10种麦片中有7种糖的含量在第二或者第三位。

注：Which？是一家数据机构的名称。

But some research suggests if we’re going to eat sugary foods, it’s best to do it early. One study found that changing levels of the appetite hormone leptin in the body throughout the day coincide with having our lowest threshold for sweet food in a morning, while scientists from Tel Aviv University have found that hunger is best regulated in the morning. They recruited 200 obese adults to take part in a 16-week-long diet, where half added dessert to their breakfast, and half didn’t. Those who added dessert lost an average of 40lbs (18kg) more – however, the study was unable to show the long-term effects.

但是有研究称如果我们要吃含糖食物，最好早点吃。一项研究发现，身体一天中抑制食欲的激素——瘦素的变化水平与早上甜食最低摄入量一致。同时来自特拉维夫市大学的科学家们已经发现饥饿在早上最容易控制。他们招募了200个肥胖成年人接受为期16周的规定饮食，一半人早餐中有甜点，另一半没有。早餐有甜点的人平均减掉了40磅（18千克）还多的体重。然而这项研究无法呈现实验的长期效果。

A review of 54 studies found that there is no consensus yet on what type of breakfast is healthier, and conclude that the type of breakfast doesn’t matter as much as simply eating something.

一项对54个研究的文献回顾发现，对于什么样的早餐更健康还没有形成共识，并且结论早餐是什么不重要，只要随便吃点儿什么就行。

Final take

终极行动

While there’s no conclusive evidence on exactly what we should be eating and when, the consensus is that we should listen to our own bodies and eat when we’re hungry.  

虽然对于我们早餐到底应该吃什么和在什么时间吃没有确定的证据，但是人们一致认为我们应当听从自己身体的意见，饿了就吃饭。

“Breakfast is most important for people who are hungry when they wake up,” Johnstone says.

“早餐对那些早上醒来觉得很饿的人最重要。”Johnstone说道

For instance, research shows that those with pre-diabetes and diabetes may find they have better concentration after a lower-GI breakfast such as porridge, which is broken down more slowly and causes a more gradual rise in blood sugar levels.

比如有研究表明，前驱糖尿病和糖尿病患者在吃完胰岛素指数低的早餐（比如说粥）后，会发现自己有更好的注意力。这是因为这些食物消化的更慢，因此导致身体血糖水平上升地更缓慢。

Every body starts the day differently – and those individual differences, particularly in glucose function, need to be researched more closely, Spitznagel says.

每个人都用不同的方式作为一天的开始——这些个人差异，尤其是葡萄糖的功能，需要更进一步的研究。Spitznagel说道。

In the end, the key may be to be mindful of not over-emphasising any single meal, but rather looking at how we eat all day long.

最后，记得要注意一整天的饮食而不是过分强调任何一餐才是最关键的一点。

“A balanced breakfast is really helpful, but getting regular meals throughout the day is more important to leave blood sugar stable through day, that helps control weight and hunger levels,” says Elder.

“一个均衡的早餐是很有帮助的。但是一天中有规律的饮食对血压全天保持平均更重要，并且还有助于控制体重和饥饿程度。”Elder说。

“Breakfast isn’t the only meal we should be getting right.”

“早餐不是唯一需要吃好的一餐。”