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Comment by Jonanin | Hacker News Reader

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?

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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.

I wouldn't say that the parenthetical in the comment you are responding to is correct:

> 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?

In the study they found that more chewing was correlated with higher satiety and lower food intake in the follow up meal. This may show that if you are concerned about weight gain you should chew more and then you'll naturally eat less.

But is it higher satiety because your body is absorbing more nutrients? In that case, it seems to be a wash. Chewing slowly just means you can get by with less volume of food.

Yes, I also think that the raised question is really something worthy to explore, especially in the long run.

"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.

What comes out is the corn shell, which looks like corn unless you poke at it.

Source: I poked at it.

Ahhh, I wasn't ready for that citation.

Love it! You solved one of the things I’ve always had a hunch but never brave enough to prove myself.

Spoken like a true hacker.

This needs it's own separate scientific investigation.

Agreed - definitely https://www.improbable.com/ig-about/ science material and possible future winner in the making right there.

What comes out is the corn shell, which looks like corn unless you poke at it

I've heard this, but never experienced it myself. No corn shell in my stool. I've also heard people say hot sauce is just as hot coming out as going in. I've also never experienced that (whew!). I do struggle with my weight, so maybe that's why? My gut microbes are extracting every bit of all the food I eat?

> I've also heard people say hot sauce is just as hot coming out as going in.

Depends on how much you eat, leastwise based on my own experience.

There was a point in my distant youth where I thought it was amusing to put as much spicy stuff on a meal as I could manage. Red pepper flakes, cayenne powder, tabasco, etc. It absolutely did burn going out--but only for about 5 minutes. I apparently ate enough to--err--make things go numb.

It was a very weird sensation and something I never did again given how unpleasant the whole experience was.

I'd imagine the people who--for whatever insane reason--participate in ghost pepper challenges experience something very similar if they can keep them down long enough to partake of the journey to completion.

As far as I know, humans simply lack the ability to digest cellulos (corn kernel shells) and capsaicin (spicy molecule). I’m surprised you never see corn shells in your stool, but I can imagine people have varying degrees of sensitivity to capsaicin, so some might feel it spicy coming out while others don’t even though the capsaicin is there.

Well, apparently if you chew corn thoroughly you'll break down the cellulose fibers enough where you can digest the corn kernel shells. I don't pay attention to how I chew food and hadn't noticed chewing more than anyone else. Hmmm, strange! You would think being an older person and having been born, raised and still living in the corn belt and therefore eating LOTS of corn I would have seen the kernel shells sometime! Who knows? Maybe I'm a mutant who can digest cellulose better than most! :)

P.S. - In all seriousness maybe that's why I've been able to be a vegetarian for 30 years without suffering from the ill effects people typically suffer, such as excessive gas. Maybe I really do digest cellulose better than most.

Nice! Meant genuinely -- I thought this was very much in the "intellectual curiosity" spirit that this site purports to be interested in.

Move fast and poke shit?

It also looks like corn until you taste it.

Citation needed...

For science, of course.

yes, but does it actually taste like corn?

"Sweet corn is digested, otherwise there would be little point in eating it. The inside of each kernel is almost pure starch and is digested very readily." source: https://www.sciencefocus.com/science/why-is-sweet-corn-not-d...

This is less to do with chewing and more about how most people don't have gut microbes that can handle the fiber or produce necessary quantities of phytases to break it down.

Do you have references I can read up on that? Not saying you are wrong but it is something I would like know more about.

I'm just curious here, you're asking for a reference on basic human biology. Have you ever noticed that people don't eat grass, bark, and other sources of fiber in quantity? Yes, we can eat it. But humans don't digest it. This has been part of human culture since before we had agriculture.

I mean there is niche stuff like lactose tolerance, which only is present in some populations. That's a little different. I wasn't even aware of it until I moved out of the place I grew up.

The OP says "most people don't have such gut microbes" implying that some people do - that's what I was asking about.

I studied plenty of biology 25 years ago. Gut flora were not discuss in great detail back then. It's a relatively new focus of biology and I don't think it comes under "basic" human biology.

If you can find me people that can digest cellulose in quantity, that's pretty damn amazing.

Cattle and other animals are able to do so because they have multiple stomachs. Apparently bacteria in some of the stomachs help with this process.

Did you miss my first sentence?

The OP says "most people don't have such gut microbes" implying that some people do - that's what I was asking about.

If I understand correctly your original comment must be highly disingenuous. You're asking for sources you know don't exist.

While growing up in the US, I thought lactose intolerance was the niche.

Look up dietary fiber. It is, by definition, indigestible carbohydrates.

"most people don't have gut microbes that can handle the fiber or produce necessary quantities of phytases to break it down".

Doesn't this suggest that "some" people do have such microbes? Otherwise the word "most" should have been omitted. Maybe that is where my confusion arises from.

What about soluble fiber?

Corn husks are inedible, so that shouldn't be surprising. A great deal of plant matter, in particular, is fibre or char or similar that will simply pass through.

If you want to reduce absorption, particularly of fat, there's some evidence increasing dietary fibre a bit will help with that.

But in general, calories in = calories in.

You accidental tautology belies the point that the amount of calories your body burns is variable, depending in part on the number of calories your body takes in.

I think it makes the point that your body doesn't absorb all the calories you swallow. Fiber has energy value when burned in a fireplace, but not when eaten by a human.

burns, or stores

Interesting tidbit. I'm take an online course in Mexican cooking. The first unit is making tortillas. The chef covered the traditional way. You take dried corn, cut from the cob, and soak it in lime (pickling lime) water overnight. Then you grind it. I wondered how Mexicans use corn as a staple when it doesn't digest well. Question answered.

The lime helps the corn loosen its 'husk' as well... Nixtamalization also involves washing and husking the corn before grinding. The husk is the part that isn't digestible. More: https://en.wikipedia.org/wiki/Nixtamalization

I don't even want to imagine 75 Nathan's hot dogs.

Read Omnivore’s Dilemma. Corn is a human invention.

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.

But then, it takes longer to chew more. Your reasoning about finer particles has always been my intuition, too, but taking more time to chew while exposing more food surface area to digestive action ought to mean that your blood sugar will rise to the point where you are no longer hungry after fewer bites. You may tend to stop eating after consuming less food, so the total excess insulin (how much overage for how long) may be reduced.

Or it may increase, or it may go one way for some foods/people and the opposite for others.

Another intuition of mine is that when we finally have realtime monitoring of blood sugar (some future Apple Watch, for example) and exactly what was eaten when, we will discover to our "surprise" that there is so much variation in individual response to consumption of the same quantity of the same food (and even variation for the same person at different times of day and variation for what else was eaten and when) that it will be obvious why nutritional studies based on the usual averaging of crowds never seemed to converge on the right answer. Some averages are meaningless.

> when we finally have realtime monitoring of blood sugar

Continuous Glucose Monitors exist and, at least for the one I have, test your blood on a fairly regular basis (every 5 minutes). As a diabetic, getting one was life altering; the best positive change in my life for a very long time.

I would highly recommend a CGM to type 1 diabetics. I have the Dexcom G6, and the low blood sugar (current and impending) are amazing.

Even slow chewing is going to be quick relative to digestion by stomach acids, no?

(Is anyone working on non invasive blood sugar monitoring?)

I’ve seen several attempts at optical monitors. The first I became aware of was Agamatrix in early 2000s.

I doubt this is possible without some kind of catalyst. There’s just nothing all that unique about the composition or phonon modes of sugar or insulin.

There are other fluids aside from blood though. I think those have promise. Google X was working on a CGM in a contact lens. Maybe somebody is working on a CGM in dental roots. Gastric sensors may be just as good.

> but taking more time to chew while exposing more food surface area to digestive action ought to mean that your blood sugar will rise to the point where you are no longer hungry

That's an interesting take! You're probably right.

This is also evident if you blend up oats to make a smoothie. It will hit you like a ton of bricks. Eating a bowl of oatmeal doesn't have the same effect.

I just want to point out that there is no reason to be concerned by a steep rise in blood sugar unless you have a metabolic disorder. I steep rise in blood sugar is what you probably want from your food.

Even with a metabolic disorder, the steep rise in blood sugar is not the problem. The lack of a steep fall in blood sugar is a problem, however.

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

FYI, typo: you wrote "insulation" instead of "insulin".

Haha amazing. I guess I was still waking up. It's too late to edit so I must leave the mistake for all to see. Thanks for pointing it out though.

That makes lots more sense, especially in the context of highly processed food (which is basically mechanically chewed into dust)

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.

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).

> That feeling could be the difference between over-eating (going back for another helping), and mindful eating (stopping because you are full).

IIRC, a yoga book I read said that you should stop eating when you still feel slightly hungry - a point that I've anecdotally found makes sense, because if you wait a bit more, that slight hunger disappears.

Also, it says that at end of a meal, your stomach should be half full of food, quarter of water, and quarter of air. Gives better digestion. Also seems to make sense.

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.

Experiment in progress. I'll report back in 24 hours, or however long the grape takes to travel my innards.

As a parent the thought of you sticking a whole grape into your mouth and swallowing it terrifies me. Don’t tell your mother. This reminds me of a couple things one being the monkeys that eat coffee beans then poop them out to be gathered and used by humans and my dad also tells me a story about a seed people were desperate to try and grow. Everything they tried failed and the seeds would not germinate. Then one day the researchers was in a foreign part of the world and saw a painting that had a Dodo bird under the same tree eating the seeds. Something sparked a thought in the persons head and they decided to take the seeds and feed it to their turkey. Apparently after the turkey at the seeds and pooped them out they would germinate. This also reminds me of how forest trees need fires to release their seeds it seems like nature required an animal to eat these seeds and travel with them before pooping them out into some ready made soil ready to start the plant. Good luck with your grape

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Well?

Still no grape in the stool.

1. That's assuming that the grape skin cannot be dissolved by stomach acids. I highly doubt this. 2. That is also assuming it isn't like corn (maize). Corn appears whole, but it isn't: We extract carbs from it and let the bits we cannot digest pass through. It is the same process when you find "pills" in your poop.

Your stomach acid isn't that strong, only 1M HCl. Grape skins are made up of complex carbohydrates, which our bodies don't digest, bacteria in our large intestine break it down (somewhat). That concentration of acid will breakdown complex carbohydrates if exposed for a long time, but our stomachs empty in 1-4 hours.

I don't disagree that your body could extract some of it. The grape has a tear in the skin at the top, but compared to chewing? Very little is absorbed.

Which makes perfectly sense. Stronger signal glucose is coming and quicker uptake of glucose as the pieces are smaller and have bigger surface.

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

On my experience is the other way around. When I eat fast I can eat a lot, when I manage to eat slowly the hunger subsides with less meal consumed.

I can eat when I’m full too, I do that a lot actually. It’s entertainment to some extent.

Fascinating, downvoted for an observation on how I and a lot of people see food.

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