Diabetes Self-Management Blog

Refined carbs, bad; whole carbs, good. Diabetes educators and nutritionists have repeated that saying for years. Low-carb advocates say they’re wrong, that almost all carbohydrates are bad. Who’s right? Are whole carbohydrates really good for us, and how whole do they have to be?

To answer this, we have to know more about carbohydrates and more about diabetes. In particular, we have to learn about insulin signaling. As we know, people with diabetes have trouble dealing with sugars and foods that break down into sugar. Some people can’t produce enough insulin, as in Type 1, LADA, often called Type 1.5, and MODY. For others, their insulin signaling systems are not working, which is usually called Type 2. This could mean that the beta cells are not receiving signals to produce insulin, or that the muscle cells and liver are not getting signals to cooperate with the insulin.

This failure of muscle and liver cells to cooperate is called insulin resistance (IR). We used to think that the beta cells wore themselves out trying to overcome IR. Then they would fall behind, start to die, or fail to produce, and you would be left with Type 2 diabetes.

But now it appears that beta cells are not “wearing out.” They are either being damaged, or they are not receiving the signals they need to grow and to start producing insulin.

Like all other cells in our body, beta cells only know what to do because chemical messengers, produced by other cells, tell them. There are thousands of these messengers, and many are still undiscovered. One key messenger is GLP-1 or glucagon-like peptide-1. As I explained last month — please reread that blog entry if you’ve forgotten — GLP-1 is produced by glands at the far end of the small intestine, in the distal ileum. These glands produce GLP-1 mainly when stimulated by the presence of carbohydrates.

The problem is that modern carbohydrates never reach the distal ileum. They are absorbed before they get there, so the gut glands don’t produce GLP-1. Without this messenger, beta cells don’t know to produce insulin. They also don’t reproduce as fast. GLP-1 also slows the rate at which glucose (and other nutrients) is absorbed from the gut, so without it, you will get big spikes in your blood glucose level as all the carbs come in at once.

GLP-1 is so valuable that a new class of expensive drugs, the incretin mimetics, are being prescribed to make up for it. The main ones are exenatide (brand name Byetta) and liraglutide (Victoza). They act like GLP-1, stimulating insulin production (but only in the presence of glucose), slowing glucose absorption, stimulating beta-cell reproduction, and keeping the liver from releasing glucose into the blood.

Good stuff. But there are side effects, considerable expense, and they’re still not as good as the real thing. What people with Type 2, and probably other types, can do is limit carbohydrate intake to mostly carbohydrates that will actually reach the distal ileum and stimulate GLP-1 (and related chemical messengers that we might not know about yet.)

What Carbs Can Stimulate the Distal Ileum?
So now that we know what we’re trying to do, what foods could do it? Are whole grains the answer? Our beloved nutritionist Amy Campbell said about whole grains in 2008: “Whole grains contain three layers: bran, endosperm, and germ… Refined grains (think white flour and white rice) have the bran and germ layers removed.”

It certainly sounds like whole grains would stay in the gut longer. But even whole-grain flours get into your bloodstream much faster than the old, natural roots, fruits, and leaves. They often get absorbed as fast as the refined ones. That’s because they’re ground up, so it’s easier for digestive juices to get to them, break them down, and absorb them.

As a result, the only really whole grains are probably those you eat right off the plant, or close to it, like corn on the cob or brown rice. Any grains that are ground into flour or blended into processed food likely won’t reach the distal ileum.

If grains and sugars don’t reach the distal ileum, don’t trigger GLP-1, and therefore can’t be well used by our bodies, what about vegetables and fruits? Well, big chunks of starch in the form of starchy vegetables (like carrots or squash), probably won’t reach the distal ileum either. Green vegetables, especially fibrous ones, like broccoli, kale, collard greens, and cabbage, are the vegetables most likely to make it to the distal ileum. (Although, see a big list of nonstarchy vegetables here .)

Likewise with fruits. Modern fruits like humongous commercial apples, pears, and peaches also get into the bloodstream far too fast to stimulate GLP-1. Berries are better (and I’m not talking about these quarter-pound strawberries you see now. Smaller ones are best.) You can see a big list of nonstarchy fruits here.

Bottom line — if you have Type 2 (and this probably applies to some people with other types), I think these slow-absorbing, high-fiber carbohydrates can be part of your diet, and might even be healing to your insulin-signaling system. But be aware that many foods that call themselves “whole” or “whole-grain” are not that whole. They’re just slightly less processed. The real whole grains are the ones you can see — the kernels of corn or rice, or oats. Note that these three grains are also gluten-free.

But even those “good” whole grains should be eaten in moderation. And please, don’t forget the plusses of vinegar, which appears to have some of the same benefits as GLP-1.

If you want an inspirational read, see my blog entry on the art of “Helping without Helping”.


  1. Another excellent column raising key issues. I believe this line of comments far more helpful.

    There are simply far too many cases of diabetes dealing with screwed up body signalling from liver on down.

    Type 1 is clear about insulin non or under production.

    Type 2 is a useless catch all that is used to describe everyone else and current thinking on type 2 is still trapped on type one causes and effects - ie diet, reduced insulin production - add more insulin without really dealing with the myriad of underlying problems in the type 2 arena in any usefull meaning way. Thats why cases are exploding out of control.

    Posted by jim snell |
  2. http://www.fatsickandnearlydead.com/


    I watched both of these movies and there was some helpful information not normally found. Both are about diet and health. I am not affiliated with either movie. If you get a chance check one or both out. Forks over knives is in the theaters and Fat, sick and nearly dead is on netflix.

    Posted by Mike |
  3. I think Jim makes a good point. Type 1 has officially been defined as autoimmune, which means that if you don’t have antibodies, you are automatically classified as Type 2, but that’s really what I call a “garbage can” diagnosis. There are SO many things that can go wrong in the processing of glucose because so many hormones and enzymes and receptors are involved, and I think that Type 2 is merely an umbrella term for “we don’t know what’s wrong with this person!” Eventually, I think they will discover that there are many kinds of Type 2, and each needs its own individualized treatment. At the moment they just throw drugs at a “Type 2″ and hope something works. It’s scary, because so many of the new drugs end up having unacceptable risks and side effects!!

    I really enjoyed your explanation of the distal ileum function — it’s becoming increasingly obvious that the gut itself is an endocrine organ, not just a tube for absorbing nutrients. I commend you for including real science in your column!! :-)

    Posted by Natalie Sera |
  4. Natalie Sera

    Thank you for expanding my comments on type 2 so execellently and expanding the nature of my concern.

    Your comments about David’s column and inclusion of science on target and David’s comments are flushing out important concerns and thought that should lead to some better work, research and treatments for all of us with defective body signalling and operation leading to glucose out of control and resulting body damage.

    For me, yes my insulin production was off a little; but liver incorrect operation and signalling on insulin was wrecking my body.

    Today - off of actos and use lantus - one shot a day 15 units and a shot of 4 units of humalog lispro breakfast, lunch and dinner and 1/2 unit at midnight.

    That is not a lot of insulin for a 270 lb person.
    Key drug locking liver down is standard metformin taken throughout day and at night and no longer any wild liver dumps or dawn effect massive dumps in am.

    Even more interesting is that I do not take lunch and evening humalog lispro shots till after 1 hour after meal and with cgms I watch BG drop right after eating confirming that pancreas is kicking in the meal bolus from gut signalling.

    For me, there is a bigger unexplored study re liver and metformin that sits stuck in flat earth thinking. Each time I watch BG crawl up after metformin pill wears off and as new charge comes on stream,
    I see BG drop - assuming gut has nothing to add to riot.

    Therefore, David’s research and writings are super important to me.

    Posted by jim snell |
  5. I used to eat whole rye right off the hoof. i.e. whole rye kernels boiled. You cannot get less “processed” than that. Much better than bread but still in hindsight not a good food for many diabetics. Non starchy veggies a much better choice.

    Posted by calgarydiabetic |
  6. David,

    I enjoy reading your articles. I wonder if you have citations for some of the information you posted on the whole carbs and the beta cells not receiving signals. I would love to look up your references to learn more.

    Posted by Lori |
  7. I had to have surgery recently, which meant I had to stop taking my Metformin for over a week in preparation. Under my doctor’s direction, I went on a program that was very like phase one or two of Atkins (or South Beach, if you like. They are very similar). Under this plan, my type 2 diabetes (meaning my blood sugar) was completely under control. My diabetes is not as severe as many folks’, but I think most of us have been led to believe we need a lot more carbohydrate than what is actually necessary. And I agree with the assessment that we’re also being led to believe that some “whole grain” foods are better for us than what they actually are.

    Posted by Sonya |
  8. The use of vinegar(white or cider)after a meal may decrease the need for the use of antacids after as well.

    Posted by Rose |
  9. They said whole foods are good for you.

    Does not work with purple sweet potato. Sugar readings go to the roof, even if eaten with some of the skin.

    Posted by BimBam |
  10. They , the VA, said in 2005 that i was prediabetic type 2. wanted to start me on Metformin. I refused. Now they say i am full blown type 1 and want me on insulin. that’s cuz i ran out of money and wasnt taking my health food store stuff for a couple of months. If i take Dr. Christopher’s Pancrea Formula and Bitter Melon and Gymnea I feel great, the eyesight and nearves are being fixed and my sugar numbers are going down. I cut out all breads and noodles, pop, white sugar, white flour, follow Dr. Christopher’s mucusless diet and N W walker’s and Airolas diet too. nuts, seeds all raw, whole oats and wheat, soaked or sprouted is best, lots of veggies, some juiced, blueberries, apples bananas, a little fish and chicken a couple times a week. Dont forget fertile eggs 2 or 3 days aweek, goat dry milk and goat cheese. I also take apple cider vinegar, and Hydrogen Peroxide food grade every day. I walk or ride my bike at least 1/2 hour or more each day. And I pray for more wisdom too.

    Posted by Dotty |
  11. Great article..

    I stay away from grains as much as possible - yes even whole grains most surely can make your blood sugar take off like a rocket!

    Only your Blood Testing Meter knows for sure! Best feedback possible..

    Posted by John_C |
  12. Fntstic site here. So mny web sites like this cover subjects tht just rent covered by mgzines. I dont know how we got by 12 yers go with just newsppers nd mgzines.

    Posted by pupu987 |

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