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?
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"
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.
"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
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.
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.
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.
"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.
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.
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.
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
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.
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.
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.
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.
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
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.
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
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.
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.
My parents (tried and failed) to teach me similar values that they learned from their own parents.
But it got me thinking--I wonder if these "old guard" values are related to food scarcity? We (peoples of industrialized nations), live in a world of abundance when it comes to food. High calorie food sources are cheap and plentiful.
We don't need to chew our cheerios so much, because a machine already chewed them for us. We don't need to chew our chicken so much, because there's more where that came from.
In fact, the "chew your food" lesson in childhood always came up during meals where we ate steak, and not so much other meals. Now part of this was due to the fact that the steak was tough and chewy (they cooked it well-done). However, I think it's worth considering the fact that steak is expensive, and if I was eating steak then there was not more where that came from.
So maybe part of that "chew your food" lesson was actually a different one: "savor this food, because it's the last that you'll have until tomorrow."
Could be, my grandmother's parents were Boston brahmins I think so food was not usually scarce. My general understanding was that it's uncouth to devour or inhale your food at the table.
In that sense the nuance is not that this might be the last food you get for a while - but rather that having food is no big deal, don't make it seem like this is the first meal you've had in forever.
Another rule (not the same but similar) is to finish each course at the same time as the host, not sooner nor later.
Yeah my mom used to chastise me for eating too fast. Later i realized it was because she overcooked everything so meats were really tough and i just wanted to get it into my body as quickly as possible
Now overcooking a steak is a just sin. It should be like butter
I could chew a piece 2 times, swallow, and wait 30 seconds before eating the next piece. Or I can chew 15 times, swallow, and immediately eat the next piece. If it's the 30 second wait that is the key rather than the actual chewing then you can tell people to focus on that rather than counting chews.
It's about the amount of pre-processing the food gets in our mouth, so the effect they're measuring depends on the time the food has spent in the mouth, in contact with enzymes from saliva, and how finely ground it was by our teeth. A bit hard to put that into a single easy to understand metric.
yes, that is the assumption, but I couldn't find anywhere in the paper that they controll for time as suggested by the upthread posts -- I admit to only skimming it though.
The wisdom I received in childhood was to put your knife and fork down between bites, to regulate eating speed. Is chewing longer better? That's what I wished this study told me.
I, too, enjoy mastication with my denticles, fellow human! How is your [star] light cycle going? Can I interest you in some perambulation in a sparsely populated area later on?
Have you ever seen the web comic Strange Planet? [1] I tell people it's a great way for them to understand what high-functioning autism feels like for some of us and it's hilarious.
>> 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.
No it's bad if your friends gobble up all the food without leaving anything for someone that eats slower. I would never do that even if I was a fast eater. But also, as the other reply pointed out, it was tongue in cheek.
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)
> 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.
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.
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
I worked on a process to reduce a vatful of long-chain polysaccharides to dextrose. The resulting dried powder was shipped as 'coffee creamer'. But not sure how efficient the process would be on starch - we started with much shorter chains (sucrose etc but some starch).
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.
> 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.
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.
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.
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.
I think it's a joke based on the fact that you don't chew soylent.
It is interesting to think about the fact that soylent is effectively "chewed for you" via pre-processing. Maybe if we could chew soylent then it would be a better food substitute, because we would feel fuller after eating it.
