Why Grains Are Bad–Part 1

November 28, 2011 in Categories: by

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Before committing to paleolithic nutrition, I read a whole lot about it.  I read scientific journal articles, books, and some great blogs.  As I delved deeper and deeper into the reasons why paleolithic nutrition is so remarkably healthful, I found myself learning the detailed physiology and biochemistry behind many aspects of this diet.  Although you don’t need to go into as much detail as I have, much of this information is relevant to you and will help inform your choices as you continue to experiment with a paleolithic lifestyle.  I will try to distill the most salient points for you.  First, up:  Why are grains bad for you?

Grains have a particularly high concentration of two types of lectin.  Lectins are a class of proteins (of which gluten is one) that are present in all plant life to some degree.  Two sub-classes of lectins, prolamins (like gluten) and agglutinins (like wheat germ agglutinin) are of particular concern for human health.  These lectins are part of a plant’s natural protective mechanism (from predators and pests) and are usually concentrated in the seeds of the plant (which is why grains and legumes have so much).  So what happens when we eat these proteins?  Similar to what occurs in individuals with celiac disease (basically, a super exaggerated form of the sensitivity we all have to gluten and other lectins), these lectins can either damage and kill the cells that line your intestines or directly causes spaces to open up between your gut cells.  This causes little holes in your intestines; so, things that are not supposed to get into your blood stream leak out.  This “leak” is made worse by the fact that lectins bind to sugars and other molecules in the gut and then “help” these random other molecule leak into the blood stream.  There are many things in your gut (like E. coli) that are supposed to stay there; and, when they leak into the blood stream, they cause a low level of systemic inflammation.  This can set the stage for many health conditions, including cardiovascular and auto-immune diseases.

There are many lectins and some are more harmful than others.  Gluten is by far the most damaging lectin, but non-gluten containing grains still contain lectins. Wheat germ agglutinin is a very close second in terms of negative impacts on health (it has the added effect of stimulating inflammation), which is why the simple act of removing wheat from your diet a la Wheat Belly by Dr. William Davis can make such a difference to people’s health.  And while some of the other “blacklisted” foods are okay for occasional consumption (like dairy, beans and rice), I suggest a lifelong dedication to gluten and wheat avoidance.  It can take up to six months for your gut to fully heal after a single gluten exposure (see How Long Does it Take the Gut to Repair after Gluten Exposure?).  Beyond the fact that some lectins are more problematic than others, dose is another important factor here.  The vegetables and fruits that our prehistoric ancestors ate in large quantities are generally very low in lectins (and typically contain lectins that interact much less strongly with the gut barrier than those in grains).  Grains (especially wheat) and legumes (especially soy) are very high in prolamins and agglutinins, the two sub-classes of lectins with the greatest negative impact on the barrier function of the gut (where the gut is supposed to selectively allow digested nutrients from our foods into our body and keep out everything else).  And, if damaging your gut lining and causing systemic inflammation isn’t enough, lectins are also anti-nutrients, which means that they stop you from absorbing many of the vitamins and minerals in your food (like calcium!).  

On top of all this, grains are highly acidic foods (at the level of your kidneys, not your stomach).  Another aspect of paleolithic nutrition is to balance your intake of acidic and alkaline foods (I will expound on acid-base balance in a future post).  Generally, meat, eggs and fish are acidic and we balance this with lots of vegetables and some fruit, which are alkaline.  When grains are in our diet, it is nearly impossible to eat enough alkaline foods to balance this out and the result is strain on the kidneys, liver and pancreas. 

If all this just whets your appetite for more detailed information, I suggest starting with Dr. Loren Cordain’s website http://thepaleodiet.com/ and The Paleo Answer.


I love this! Thank you so much for the explaination. I am transitioning to the paleo diet myself and the knowledge of what grains do to my body is making the change feel like its saving my life instead of depriving me. Thank you!!!

What about sprouted grains? I honestly don’t know much about them but have heard really really good things. Once a grain has “sprouted,” is it paleo friendly? Thanks!

Hey I too would like to know if sprouted grains are okay, or at least semi-okay! I know they’re okay in weston price’s view…and for those of us who struggle to keep weight on it seems a good option..

All grains and grain products should be eliminated for 30-90 days. You are welcome to try reintroducing sprouted grains if you would like to see how you tolerate them at that point. – Christina, Sarah’s assistant

Out of curiosity, have you ever read Mat Lalonde’s criticisms of the paleo diet? He has some good points. You wrote a good article. I was just wondering what you thought of him. thanks

I super respect Mat Lalonde. I think many of his criticisms are outstanding points and some are an overstatement in the other direction. My article (Re)defining paleo is in part inspired by some of his points from his Organic Chemists Point Of View of Paleo lecture.


do you have any research articles or established scientific sources to support these claims? I just want to be sure and learn more.


Corn grits? And organic? I think the real question to answer is how you feel you do with them. We have organic locally-grown pop corn as an occasional treat in our home and we all seem to tolerate it well.

Could you please post the journal articles that you got your information from? I would love to read the solid science that backs this up to support this claim.

I am 58 and just found out I’m borderline diabetic and I’m slim enough to control it via diet. No milk, butter ok.(A little milk in the morning coffee is ok) But I cut out the grains also (which I used to crave) EXCEPT swedish krispbread (knackebrod). Knackebrod is flat, hard, yeast free and is ALL rye. Rye naturally has no gluten. My dad had that when we were kids, I grew up on it and he lived to be 90. It is a staple in Scandinavian countries in lieu of bread. And they have many healthy people there if they stay away from the Mickey D’s.

phosudo science bull shit . Sorry kids.. it true crap.. fact is ANY whole food is ok . Give your collective heads a shake and MAYBE embrace some common sense ( just for a change)

Further more, this type of garbage advice has led to an epidemic of “peanut” allergies and a host of other ” allergies” previously unheard of. All thanks to half truths like this contained in this web site and related web-sites. Follow this: eat less , move more. Cut out man made processed garbage and ” food like” products.. Do this and you and your children will be fine. EVERYTHING else is a book designed to separate you from your money and has NOTING to do with your health , your well-being, or anything that remotely resembles common sense.

It’s hard to know if any of this has any validity without proper citations, it is true, but you fail to cite anything as well.

I sure wish people would stop claiming they have scientific evidence of anything without citing some actual research.

Keep in mind how our brains work. It doesn’t matter if its a quantum physicist, Medical Doctor, nutritionist, teacher, fireman, soldier, governor, male, female, or soccer Mom. Our brains don’t like change! It takes a while to accept and believe new information. Science is a great way to change our beliefs, but testing it yourself is usually better. I tried it, and it worked for me. It gave me a (90% subjective) arthritis pain reduction, even though I thought it wouldn’t, it did. It seems to work even if your brain doesn’t want you to believe it does. After 8 months I’m beginning to believe.

Friends, I have been transforming my diet for the past 20 years; however, I still ate the grains and legumes, and was still quite sick, and specially gut swollen after meals. Six months ago, I totally eliminated all wheat products, grains, sugars, legumes. Apart from the fact that lost 10 pounds and I’m now at 100 lbs, I have to gut problems anymore, I can eat just about anything, but most of all, my health is the best. My daughters told me this month: Mom, this is the best health you have ever had in your life. I had half a cup of “whole wheat” in the house I was invited to celebrate mother’s day, and all my joints were swollen by Monday morning, and I DO NOT have arthritis. When your body is desintoxicated, you feel it right away. So, friend, do not complain if you have not dared to try a healthier lifestyle, and are still complaining about your lousy health. This is a 65 year old that can now do 40 yr old exercises, feel better than ever, and the energy is on woman high all the time! YEAH!

Great info, after suffering serverly with no answers finally concluded dairy protien was making me very ill. Now skin problems I suspect are caused by tomatoes. Good info keep up your information. If readers are skeptical then they are probably lucky enough to be able to tollerate these foids, but I dont appreciate their attitudes towards your ideas. Good job.

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