蔬果昔的是是非非(之四)
没看过前三集的,请补看一下。
液体热量:蔬果昔使你增加体重吗?
Liquid Calories: Do Smoothies Lead to Weight Gain?
请看Michael Greger 医生制作的小视频:
https://v.qq.com/txp/iframe/player.html?vid=s1336ifye8y&width=500&height=375&auto=0
2000年有个著名的研究是比较苏打(液体)和软糖(固体)对总热量摄取的影响。
A famous study in 2000 compared the impact of soda versus jellybeans.
试验者每天多吃28勺的糖,分别以苏打和软糖的形式摄取。
They had people add 28 extra spoonfuls of sugar to their daily diet in the form of jellybeans or soda pop.
然后,为了解身体是否对多吃的糖做出调整,测量每天摄取的总热量。
Then, they measured how many calories they ate over the rest of the day to see if their bodies would compensate for all that extra sugar.
这是软糖组在试验开始前摄取的总热量(右边灰色)。但吃了一把软糖后,身体记录下来所有额外摄取的热量,结果是一天中其它食物吃少了。
This is how many calories the jellybeans group was eating before the study started. But when eating handfuls of jellybeans, their bodies registered all those extra calories, so they ended up eating less of everything else throughout the day.
所以,即使加上了软糖的热量,一天中总的热量摄取基本保持不变。(右边黑色)
So, even adding the jellybean calories, they were eating pretty much the same number of calories before and after adding the jellybeans to their diet.
但是在苏打组,这是试验前的热量摄取(左边灰色),尽管多喝了苏打,但每天还是吃同样多的食物。
But in the soda group, this is how much they started eating, and despite all the added calories from the cans of soda they were drinking everyday, they kept eating about the same amount.
所以,加上苏打的热量,难怪喝苏打一个月后体重都增加了。
So, with the soda calories added in, no wonder they gained weight after a month of drinking soda.
身体好像不会认出以液体形式摄取的热量,所以没有减少食欲而少吃食物。
Their bodies didn’t seem to recognize the extra calories when they were in liquid form, so didn’t compensate for them by reducing their appetite so they’d eat less the rest of the day.
因此研究人员建议,如果你想增加体重的话,可以利用身体对液体和固体的不同反应规则。
This lack of regulation may be used to your advantage, the researchers suggest, if you want to get fat.
但如果你不想增重呢?
But what if you don’t?
如果你在早餐时吃的是蔬果昔而不是固体食物,你的身体会不会以为你没吃早餐,而让你在午餐时觉得特别饿而比平时多吃食物使你体重增加?
If you drink a smoothie for breakfast instead of a solid meal, will your body think you skipped breakfast and makeyou so ravenous at lunch you’d eat more than you normally would and end up gaining weight?
好吧,首先固体和液体热量的影响是真的吗?
Okay, well, first, is this solid versus liquid calorie effect real?
苏打和软糖不仅物理形式不同 – 它们的配方也不同。
Soda and jellybeans don’t just differ by physical form — they have different ingredients.
这就是很多类似研究的问题。使用的是不同类的食物。
That’s a problem with a lot of these kinds of studies. They use dissimilar foods.
就像这个研究比较液体和固体早餐;或者用果汁和脱脂奶做早餐,或者用加了蓝莓和苹果的燕麦。
Like this study comparing liquid to solid breakfasts; they either got fruit juices and skim milk for breakfast, or oatmeal with blueberries and apples in it.
瞧瞧,研究对象吃燕麦后比较不会饿。矮马
And lo and behold, study subjects were less hungry after the oatmeal. Duh. That may not be a solid versus liquid effect; Those are completely different foods.
要测试液体和固体的影响必须用完全一样的食物只是形态不同而已才行。
To test for a solid versus liquid effect you’d have to use the exact same food in just two different forms.
即使这个研究也是有瑕疵的。它声称饭前吃苹果会减少饥饿感而使你总体上热量摄取减少,而打成糊的苹果则效果没有这么好。
Even this study was flawed. It purported to show that eating apples before a meal is so good at filling you up that you eat fewer calories overall, but that puréed apples weren’t as effective.
但他们并不只是把苹果打成糊,而是先把苹果烤了45分钟,这可能改变了身体处理苹果的方式。我看了太多这样的研究都无法说服我液体和固体的不同影响。
But they didn’t just blend the apples, they baked them for 45 minutes first, which may change how the body handles them. I had seen all these studies but was just not convinced there was a solid versus liquid effect.
后来,这个研究出来啦。
And then, this study was published.
固体食物 - 水果沙拉,由苹果、杏和香蕉组成,再喝上三杯水。 或者,拿其中的两杯水,加上那些水果打成水果昔,再喝上第3杯水。所以是同样的食物:一个是固体形式;一个是液体(水果昔)形式。结果如何呢?
A solid fruit salad, with raw apples, apricots and bananas, with three cups of water to drink. Or, take two cups of that water, add it to the fruit, make a fruit smoothie, and then just drink that third cup of water. So the identical meal: one in solid form; one in smoothie form. What happened?
吃果昔的人明显感觉没有那么饱。等量的食物,等量的纤维,但果昔的形式没有食物原本形式有饱腹感。
People felt significantly less full after the smoothie. Same amount of foods, same amount of fiber, but in smoothie form it just didn’t fill people up as much as eating fruit au naturel.
原本,我们认为是因为少了咀嚼过程。咀嚼的动作可能会释放一个饱腹的信号,一个“我已经吃饱了”的信号。
Originally, we thought it was the lack of chewing. The act of chewing itself may be a satiety signal, an I’ve-eaten-enough signal.
确实如此,对比每口咀嚼35次和每口咀嚼10次,如果叫人吃意粉直到感觉刚好饱了,那些被强迫每口咀嚼35次的会少吃1/3 杯。
And indeed, comparing 35 chews per mouthful to 10 chews per mouthful, if you ask people to eat pasta until they feel comfortably full, those forced to chew 35 times per bite ended up eating about a third of a cup less pasta.
所以,我们得出这样的结论:我们有了固体和液体效果的证据,了解了机制,并且,就象科学上经常发生的事,当我们以为万事大吉准备收弓时,悖论出现了。
So, there we have it: we have the proof of the solid versus liquid effect, we have the mechanism, and, as so often happens in science, just when we have everything neatly wrapped up with a bow, a paradox arises.
就是这个案例,伟大的汤悖论。
In this case, the great soup paradox.
汤,搅碎成糊状的汤,特别是搅碎的蔬菜热汤比同样的块状蔬菜更有饱腹感。
Soup, puréed, blended soup, essentially a hot green smoothie of blended vegetables is more satiating than the same veggies in solid form.
同样的一餐,液体状态比固体状态更有饱腹感。
The same meal in liquid form was more filling than in solid form.
所以,也许是因为咀嚼 – 实事上,根本不存在液体和固体效应一说,因为冷的糊状食物饱腹感较小,而热的糊状食物更有饱腹感。
So, it can’t be the chewing - in fact, there doesn’t appear to be a solid versus liquid effect at all, since cold smoothies appear to be less filling, but hot smoothies appear to be more filling.
所以如果把汤作为第一道菜的话,主菜就会少吃很多,即使加上汤的热量,吃的总体热量也会比较少。
So filling, that when people have soup as a first course, they eat so much less of the main course, that even when you add in the calories of the soup, they eat fewer calories overall.
所以,怎么解释这个悖论?
So, how can we explain this paradox?
也许打成糊的水果没有固体水果更饱腹,但打成糊的蔬菜比固体蔬菜更饱腹?
Maybe puréed fruit is less filling than solid, but puréed vegetables are more filling?
我猜你也许尝试做苹果汤或类似的东西,但谁会去做呢?
I guess you could try making apple soup or something, but who’s going to do that?
普渡大学。他们把一杯苹果汁和两杯苹果酱混在一起搅拌成液体,再加热它。
Purdue University. To prepare apple soup, they mixed about a cup of apple juice with two cups of applesauce, liquefied it in a blender, and heated it up.
如果你让很饿的人吃3个苹果,在吃苹果的15分钟之内,就几乎不饿了。
If you have people eat three actual apples instead, they start out pretty hungry, but within 15 minutes of apple eating, they were hardly hungry at all.
喝3杯苹果汁不怎么会降低饥饿感,但如果是汤呢,只是热的苹果汁和苹果酱混合物?
Drinking three cups of apple juice didn’t cut hunger much at all, but what about the soup, which was pretty much just hot apple juice with applesauce mixed in?
热的苹果汤降低饥饿感的程度几乎跟吃完整苹果一样,1小时后效果还更好,并且在降低全天热量摄取方面打败了吃完整的苹果。
It cut hunger almost as much as the whole apples, even more than an hour later, and even beat out whole apples for decreasing overall calorie intake for the day.
汤到底有多特别呢?喝汤和长时间咀嚼食物得到的同样结果,与喝蔬果昔的区别在哪里呢?
What’s so special about soup? What does eating soup have in common with prolonged chewing that differentiates them from smoothie drinking?
时间。
Time.
咀嚼35次比咀嚼10次需要差不多2倍时间,想想喝一碗汤与喝蔬果昔需要时间的比较?吃的慢会降低热量摄取。
It took about twice as long to chew that many times, and think how long it takes to eat a bowl of soup compared to drinking a smoothie? Eating slower reduces calorie intake.
或者,我们假想喝汤会更饱腹,就象是安慰剂效果。饿与饱的感觉都是很主观的。
Or, maybe we just imagine soup to be filling and so, like a placebo effect it is. Feelings like hunger and fullness are subjective.
人们更倾向于根据他们想象的食物含热量来报告饥饿程度而不是实际的食物含热量。
People tend to report hunger more in accordance with how many calories they think something has rather than the actual caloric content.
如果研究失去短期记忆的人,就象电影《凶心人》一样,他们不记得1分钟前发生的事,他们会吃多了食物,因为会忘记刚刚吃过了,表明我们对饥饿的判断是多么不靠谱。
If you study people with no short-term memory, like in that movie Memento, where they don’t remember what happened more than a minute ago, they can overdose on food, because they forgot they just ate, which shows what poor judges we are of our own hunger.
而且这不只是主观影响。
And it’s not just subjective effects.
在这个著名研究中,“想法胜过奶昔”,如果提供2杯奶昔,1杯描述成“过度丰盛”,另1杯描述成“无负罪感”,人就会有不同的激素分泌,即使两杯奶昔是完全一样的。
In this famous study, “Mind Over Milkshakes,” if you offer people two milkshakes, one described as indulgent — decadence you deserve, the other sensible — guilt-free satisfaction, people have different hormonal responses to them, even though they were being fooled and given the exact same milkshake.
最后,也许是因为汤是热的,热的比冷的更有饱腹感。所以,关于汤的迷思我们怎么弄清楚是因为时间、想法或者温度呢?
And finally, maybe it was just because the soup was hot, and warmer foods may be more satiating. So, how do we figure out if the solution to the soup mystery was time, thought, or temperature?
如果这个研究有第3组。一组吃固体食物,一组“喝”液体食物。如果再有一组是“吃”液体食物就好了。他们真的这样做了。
If only this study had a third group. They had a solid-eating group, and a liquid-drinking group. If only they had a liquid-eating group too. They did.
他们提供了一碗水果昔,冷的,用勺子来吃 - 完全不象是喝汤。
They also offered the fruit smoothie in a bowl, cold, to be eaten with a spoon — very unsoup-like.
所以如果是因为想法或温度,喝果昔的饱腹程度会下降。
So if it was thought or temperature, the fullness rating would be down by the liquid drinking — the smoothie.
但如果吃的速度减慢而使“吃”汤的饱腹效果象吃固体食物一样的话,那么数据应该与吃固体食物的一组接近。
But if it was just the slowed eating rate that made soup as filling as solid food, then the number would be up closer to the solid-eating group.
吃液体确实跟吃固体食物的饱腹程度一样高,喝蔬果昔感觉不象吃固体食物饱腹的唯一原因是我们喝的太快啦。
And it was exactly as high, meaning the only real reason smoothies aren’t as filling is because we gulp them down.
只要我们喝的足够慢,蔬果昔的饱腹程度就象吃固体食物一样。
But if we sip them slowly over time, they can be just as filling as if we ate the fruits and veggies solid.
哇,这个研究考虑的真周到!
Wow, this study thought of everything!
你还不知道另一半故事。他们还想知道高脂肪含量的蔬果昔是否也一样。
You don’t know the half of it. They also wanted to see if it would work with high-fat smoothies.
什么?杏仁酱或核桃酱?不是,他们用猪的五花肉打成了液体状。
So, what, almond butter or walnuts? No, they used a liquefied fat smoothie of steamed porkbelly.
我猜有时“五花肉昔”也会抑制你的食欲。(五花肉昔太恶心了
I guess sometimes smoothies can suppress your appetite.