Dude! Chew Your Food!

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Have you ever had a meal that you don’t remember eating, you look down and all the food is just… gone? Or do you have to fit eating into your busy schedule so the quicker you can be done the better? Or do you eat really fast all the time because as a kid you had to beat your siblings to the food or there wouldn’t be enough?

If you answered yes to any of those questions, then you probably don’t chew your food enough. And this may be causing problems that you don’t even realize are related.

Before you tune me out thinking this is all about being present with your food, it’s not. (Although being present while you eat has been shown to prevent over-eating and increase satiety with food… but I’ll save that for another day.) Rather, I want to tell you about the physiological impact of not chewing. So, let’s start with what chewing food does for us…

What does Chewing Accomplish?

1. Chewing is the very beginning of digestion.

The technical word is mastication and it increases the surface area of the food so that enzymatic breakdown is more efficient. Imagine you have a gigantic block made out of Lego’s and you must paint every side of every Lego purple. Breaking the giant block apart so you can dip each Lego in the purple paint is much faster than dropping the whole block in a bucket and waiting for the paint to seep through every crack.

Chewing is the process of grinding food into smaller and smaller pieces so the next step (digestion via enzymes) can happen more quickly and easily. Once the food is in smaller particles, the enzymes don’t have to work so hard to break the food into small enough molecules that the nutrients can be absorbed by your intestines.

2. Chewing triggers the release of saliva which is the first step in enzymatic digestion of carbohydrates and fats.

Saliva contains amylase, the primary enzyme that breaks carbohydrates into disaccharides and lipase, the primary enzyme that breaks fats into smaller molecules. By thoroughly chewing your food, you ensure that all the pieces get coated in saliva so the enzymes can start working on the carbohydrates and fats in the food.

This is an important step because, although your small intestine also produces amylase, lipase and other enzymes, the acid released by your stomach inactivates salivary amylase so digestion of carbohydrates basically stops in your stomach. If you haven’t chewed enough and gotten enough saliva in your food to start the breakdown of carbohydrates before swallowing, that lump of carbs will sit in your stomach getting in the way of protein digestion (which primarily occurs in the stomach) and fat digestion.

3. Keeping food in the mouth and chewing it tells the rest of your gastrointestinal tract that it’s time to do its job.

The motion of chewing, as well as the contact of the food with your taste buds, sends signals to the rest of the necessary organs that they need to do something to take care of the food you’re about to swallow. The messages tell:

  • The valve at the top of the stomach to relax so that food can easily pass from the esophagus into the stomach,
  • The stomach to:
    • Release acid so that you can breakdown protein and
    • Stop producing ghrelin, the hormone that tells your brain you are hungry,
  • The pancreas to release enzymes into the small intestine (to further breakdown carbohydrates, fats and protein) and bicarbonate to neutralize the stomach acid (so you don’t digest your intestines),
  • The small intestine to release hormones, such as:
    • Cholecystokinin (CCK), which stimulates the gall bladder to release bile into the small intestine so fat can be completely digested and triggers the vagus nerve which tells your brain you’ve had enough food, and
    • Glucagon-like peptide (GLP)-1 and peptide YY (PYY) which have been shown to control blood glucose and triglyceride levels, and body weight.

What is the Outcome of Not Chewing Food Enough?

Now that you know what food chewing triggers in the body, you’ve probably already started to figure out what happens if you don’t chew food enough. And just to be sure we are all clear about it, let me tell you exactly what can happen if you don’t chew enough…

1. Food is not digested completely and/or efficiently, which can cause:

  • Heartburn / acid reflux as the food sits in the stomach longer while the stomach tries to digest it (note: some foods will ferment while they sit in the stomach),
  • Incomplete absorption of nutrients because they could not be broken into small enough pieces to cross the intestine wall,
  • Small Intestine Bacteria Overgrowth (SIBO) as the bacteria feast on partially digested food and then reproduce at a rapid rate (note: most of your intestinal bacteria lives in the large intestine, and that’s where we want to keep it), and
  • Bloating / diarrhea / constipation as greater quantities of undigested food make it to your large intestine where the good (and bad!) bacteria gobble it up.

2. Insufficient release of hormones related to chewing, which can cause:

  • Increased food intake due to lack of feeling satisfied (the hormones that tell you to stop eating don’t get to the brain in a timely manner based on the amount of food consumed; note: it takes somewhere around 15 – 20 minutes for your brain to get the message that you are full),
  • Blood sugar imbalance because GLP-1 doesn’t stimulate the pancreas to release insulin, and
  • Incomplete absorption of nutrients because these hormones tell other organs to help with digestion (example: CCK telling the gall bladder to release bile).

The benefits of chewing are obviously the opposite of the above… better nutrient availability and absorption, reduced risk of digestive issues such as heartburn and bloating, and easier weight and blood glucose management.

How can You Chew More?

I’m so glad you asked! 😉

Of course, everything we do is a habit. Eating fast is a habit, and chewing more must become a habit. Fortunately, there are several things you can do to help you build the habit of chewing your food sufficiently.

By the way, chewing sufficiently means chewing each bite of food 40 times.

With that goal in mind, here are my suggestions for getting to this scientifically-backed magical number of 40 chews per food bite:

  1. Take smaller bites of food. You probably have a habit of how long you keep a bite in your mouth. Although smaller bites doesn’t specifically increase the number of chews, it will be sure that what is in your mouth has a better chance of being broken down. For example, if you swallow quickly because you are dining with someone else and you need to be ready to respond verbally, a smaller bite means you can be ready to respond faster without swallowing large chunks of unchewed food. As well, taking smaller bites will prevent you from swallowing some food just to make room in your mouth to chew the food that’s left.
  2. Put your fork down between bites of food. Again, this doesn’t necessary increase the number of chews, but it does help you focus on the chewing and not on the next plate-to-mouth movement of the fork.
  3. Chew everything you put in your mouth (that’s not in a capsule, of course). Whether it’s mashed potatoes and pudding or steak and carrots, everything that goes into your mouth should be chewed. There is an old saying that you should “Chew your drink and drink your food.” The idea is that even beverages (except water) have nutrients that need to be digested, so chewing mixes the beverage with your saliva to begin the digestive process. The same holds true for smooth foods. Okay, maybe chewing juice feels weird, but chew everything else, including your smoothie!
  4. Chew food until there is no texture left. For example, if you are eating broccoli, can your tongue still feel the difference between the stalks and the florets before you swallow? If so, then keep chewing because it’s not ready for your stomach yet. (By the way, this is what is meant by “drink your food” above… chew it enough that it is smooth like a drink when it goes down.)
  5. Count the number of times you chew. Counting the number of chews will make you mindful of how many times you are actually chewing. You don’t have to do this at every meal or even every bite of every meal. But, once in a while take the time to count your chews and confirm that you are moving closer to that magical number of 40 chews for each bite.

I hope I have convinced you that chewing is important if you want to get all of the nutrients out of your food, help prevent digestive issues and support you in maintaining a healthy weight.

Now tell me, do you have additional suggestions on how we can all get to the magical number of 40 chews per bite?

 
Image courtesy of Pixabay.

Sources:
— Iowa State University. Chew on this: study finds additional chewing reduces food intake in young adults. Accessed on January 28, 2016. http://www.news.iastate.edu/news/2012/apr/chewing#sthash.FH6ugSFI.dpuf
— Keller DM. Thorough Chewing Raises Hormones Regulating Food Intake. In Medscape Medical News. September 13, 2011. Accessed on January 28, 2016. http://www.medscape.com/viewarticle/749504
— Mercola J. 7 Important Reasons to Properly Chew Your Food. July 31, 2013. Accessed on Janujary 28, 2016. http://articles.mercola.com/sites/articles/archive/2013/07/31/chewing-foods.aspx
— Smeets PA, Erkner A, de Graaf C. Cephalic phase responses and appetite. Nutr Rev. 2010;68(11):643-55.
— The George Mateljan Foundation. Why is chewing such an important part of digestion? Accessed on January 28, 2016. http://whfoods.org/genpage.php?tname=dailytip&dbid=337

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2 Comments

  • Living and teaching in China, I note that almost all of the students are quite lean, and they eat their food very quickly. I can sit down for a meal at the cafeteria and watch 3 groups of students eat their meals at the table beside me before I am done. I also wonder if the food enters your stomach under-chewed, will that cause your body to recover fewer nutrients from it – including the main ones: carbs, fats, and proteins. It seems that the advice has been to chew slowly to improve digestion and allow the body to tell you it is full (plus the assorted others about gut bacteria and enzyme action) – but I wonder if this my be oversimplifying and hanging too much on one school of thought (I know we all assumed the food guide was correct until it wasn’t). If you don’t fully chew your chewy noodles – will they end up just passing through – reducing the amount of carbohydrates that will be absorbed, and leaving your stomach full for longer?

    • You have made an interesting observation and asked a thoughtful question, to which I don’t know the answer! The digestion that occurs in the stomach is primarily protein with just a little fat digestion taking place. Carbohydrate digestion starts in the mouth, but is halted in the stomach as the acid of the stomach inactivates the carb digesting enzymes. Carbohydrate digestion resumes in the small intestine. Perhaps the lunches consumed in China are less protein heavy and the carbohydrates less complex, so don’t need as much initial digestion in the mouth?

      Of course, almost any one suggestion related to food and nutrition is overly simplified, especially if it is stated in the context of being a silver bullet problem solver. That’s why I try to write “can cause” and “may occur” when talking about pretty much any topic. Because every body is different and, therefore, will react differently to a suggestion since that change never occurs in a vacuum and there are a million other factors at play.

      Off the topic at hand, it must be fascinating to live and teach in another country. Experiencing the food alone would be fantastic, never mind the exposure to a different culture and ways of thinking. So cool!

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