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Chewing Food More Thoroughly Results in Reduced Insulin Output (2013)

279 points| leksak | 5 years ago |pubmed.ncbi.nlm.nih.gov

124 comments

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[+] Jonanin|5 years ago|reply
The title appears to be wrong. Chewing more increases insulin concentration:

  Meanwhile, plasma concentrations of glucose (P= 0·024), insulin (P< 0·001) and GIP (P< 0·001) were higher following the forty-chews meal."
Doesn't this suggest that if you want to eat a lot of food but don't want to absorb too much of it (i.e., are concerned about weight gain), you should chew less?
[+] xenonite|5 years ago|reply
Indeed, the hacker news title appears to be wrong.

But your conclusion and the paper's title is right:

"Increasing the number of masticatory cycles is associated with reduced appetite and __altered__ postprandial plasma concentrations of gut hormones, insulin and glucose"

One may also add (2012) to the title.

[+] hutzlibu|5 years ago|reply
"Doesn't this suggest that if you want to eat a lot of food but don't want to absorb too much of it (i.e., are concerned about weight gain), you should chew less?"

Erm, did you never noticed how some food like corn comes out on the toilet pretty much unchanged(and therefore not digested) if you ate in a hurry before?

So obviously yes, even without complex chemical analysis your theory seems to be right.

[+] hliyan|5 years ago|reply
This has always been my intuition: more time for the enzymes in saliva to work, and finer particles and more surface area for stomach acids to attack means faster digestion. Which in turn means a steeper rise in blood sugar.
[+] aaronscott|5 years ago|reply
Thank you for posting this!

This physician summarized studies[0] that showed that blended food spiked insulation vs. the same food that was chewed. His information seemed solid, so this title was surprising to see.

0 - https://www.youtube.com/watch?v=qMO-5mq3crU&t=16s

[+] m463|5 years ago|reply
That makes lots more sense, especially in the context of highly processed food (which is basically mechanically chewed into dust)
[+] dmos62|5 years ago|reply
Anecdotally, I think chewing more brings satiation sooner, so you eat less. When we're really famished, we eat fast with less mastication. It's like you forget to chew. Consciously chewing more might bring you out of that devouring mode. Just speculating.
[+] nyghtly|5 years ago|reply
Yes; however, if our concern is weight gain, then I believe that this passage is more important:

> Compared with fifteen chews, chewing forty times per portion resulted in lower hunger (P= 0·009), preoccupation with food (P= 0·005) and desire to eat (P= 0·002).

If you chew more, then you will feel fuller by the time you finish your meal. That feeling could be the difference between over-eating (going back for another helping), and mindful eating (stopping because you are full).

[+] refurb|5 years ago|reply
This seems much more intuitive. The more you chew, the greater the surface area, the more rapidly carbohydrates are released or hydrolyzed by enzymes.

If you were to swallow a grape whole, you'd probably pass it whole as well and none of the carbohydrates would be released.

[+] heisenbit|5 years ago|reply
Which makes perfectly sense. Stronger signal glucose is coming and quicker uptake of glucose as the pieces are smaller and have bigger surface.
[+] tartoran|5 years ago|reply
If you chew less not as much will fit in your stomach and will feel full quicker. Digestion would also be quicker. Not sure about the sugar level though
[+] tlb|5 years ago|reply
I wish the control was waiting for the same interval between bites. As it is, the study measures the combined effect of more chewing and slower eating.

Also, the control is 15 chews? My experience of teenage boys eating pizza is 3 chews max.

[+] hammock|5 years ago|reply
My grandmother (who was very old guard proper type) taught us that every bitter should be chewed 26 times before swallowing. And of course, out your utensils down between bites.
[+] coldtea|5 years ago|reply
>As it is, the study measures the combined effect of more chewing and slower eating.

Don't those two go together naturally?

[+] unbalancedevh|5 years ago|reply
>> Compared with fifteen chews, chewing forty times per portion resulted in lower hunger (P= 0·009), preoccupation with food (P= 0·005) and desire to eat (P= 0·002).

It's a good thing, because while I'm taking 40 chews per bite of pizza, all of my buddies are inhaling theirs, and there's none left after I've finished my slice.

[+] emsy|5 years ago|reply
As a slow eater myself: Get better friends.
[+] pftburger|5 years ago|reply
My gut feel (...) is that not controlling for time per unit of mass consumed invalidates the result, as hormonal signals are slow.

IE, 25g per minute chewed 15 times vs 25g per minute chewed 40 times.

This would be highly dependant on the type of food. Bread (and pizza) chunks break down well in the gut, in comparison to mushrooms that hardly break down at all after chewing.

Insulin is released in response to blood sugar. Guesswork extrapolation : Chewing more increases surface area increasing the speed of digestion. I am not sure how chewing interacts with the amount of overall time food spends in the gut.

Still very interesting work. I would love to see an analysis of stomach acid production in relation to chewing cycles.

Of note, and correct me if I am wrong, but isn't n30 the minimum for statistical significance? (even though n30 is still laughably low, and id prefer n3000)

[+] James_Henry|5 years ago|reply
> Of note, and correct me if I am wrong, but isn't n30 the minimum for statistical significance? (even though n30 is still laughably low, and id prefer n3000)

It depends on the size of the effect, among other things. Maybe you are thinking about student-t distributions being approximated by normal distributions?

> Insulin is released in response to blood sugar.

This is true, but is only part of the picture. There are other hormones like incretins. There is even what they call the cephalic phase insulin response that occurs before blood glucose concentrations increase. I think it even can occur just from imagining eating food.

[+] lucioperca|5 years ago|reply
The title is wrong chewing carbohydrates for long will break them down to sugar. Try chewing bread for some minutes or fall a sleep with bread in your mouth. This will taste quite sweet. Hence chewing longer bread (pizza) will become more sugary and your insulin output rises. It is also written in the abstract.

The paper reports that more chewing lead better satiety and facilitate glucose absorption. From what I understand this means that they chewing gives you more net energy out of your carbohydrate food.

[+] nimish|5 years ago|reply
Assuming the paper is right and the title is wrong:

Of course? Insulin is the hormone that regulates uptake of sugars and mastication releases simpler sugars by literally cracking bigger ones? Weve known that the digestion of carbs begins in the mouth.

Processed foods are notorious for higher glycemic index numbers and in many cases they are simply externally pre-masticated by grinding, thereby skipping a step that might have some sort of feedback mechanism

[+] srtjstjsj|5 years ago|reply
Can you literally crack a carb into a sugar? I don't think so. Your pepsin can chemically separate it though.
[+] chewz|5 years ago|reply
Reminds me of The Great Masticator Horace Fletcher from hundreds years ago.. "Nature will castigate those who don't masticate."

https://en.wikipedia.org/wiki/Horace_Fletcher

Franz Kafka chewed his food excessively to the extend that people refused to eat dinner with him.

[+] layoutIfNeeded|5 years ago|reply
Anecdotal experience: when I was bodybuilding and eating 5-6 meals a day, I've found that constantly chewing on bubble gum aided my digestion and eliminated any bloating after meals.
[+] lambdaba|5 years ago|reply
It's the saliva, this is a pretty evident result in my view, digestion starts with chewing, obviously saliva plays a central role.
[+] lifeisstillgood|5 years ago|reply
So everyone's parents and grandparents were right ! Science !
[+] sradman|5 years ago|reply
> The results suggest that a higher number of masticatory cycles before swallowing may provide beneficial effects on satiety and facilitate glucose absorption.

I wonder if the satiety increase isn’t due to spreading consumption over a longer period of time. Increasing the time between bites might also improve satiety. I didn’t read the full paper, this point may have been addressed.

[+] jcims|5 years ago|reply
I’m sure it has nothing to do with this but my youngest used to chew her food forever when she was a kid. Like over a minute per bite. I inhale my food so i was glad she was taking her time, but we ultimately coached her to speed it up a little.

Fast forward a few years and her pancreas tapped out...type 1 diabetes.

[+] qwerty1234599|5 years ago|reply
Anecdotal experience: Chrewing food thorougly also reduces acid reflux symptoms.
[+] peter_retief|5 years ago|reply
My Nana was right, she would take a bite of food and put her knife and fork down while she chewed, it could take quite some time to finish a plate of food. She was always thin and had good energy levels.
[+] recursive|5 years ago|reply
On the other hand, I've effectively added a year of free time to my life by eating as fast as physically possible all the time.
[+] m3kw9|5 years ago|reply
Chewing and saliva helps a lot to break down food before your system needs their own methods to further breaking them down. This makes sense
[+] regularfry|5 years ago|reply
Is it just me that's really annoyed they put the p values in the abstract, but not the effect sizes?
[+] grandchild|5 years ago|reply
n = 21

That seems a little low to draw conclusions from?

[+] tlb|5 years ago|reply
It depends how big the effect size is. You can conclude that falling off a 100' cliff is harmful with as little as n=2. Here, the effect size is big enough to get significance with n=21. For tiny effects like in priming studies, you need much larger samples.