Diabetes Diet

The Trouble with Fructose for Diabetes

Now that our doctors and scientists have begun to realize how big a danger that fructose is for us we can hope that the twin epidemics of diabetes and obesity can finally be halted. But for each of us individually the more important message is that we can still save our health if we avoid added fructose.


The phrase “added fructose” means the fructose that we add to what we eat. The sugar in fruit is of course fructose, but essentially all experts agree that it isn’t a problem because we get that fructose along with fiber, antioxidants, and the other good stuff in whole foods.

But added fructose includes what we simply call sugar, table sugar, or sucrose. These three terms all mean the same thing — sugar that is half fructose and half glucose. Added fructose also includes high fructose corn syrup (HFCS), the sweetener that we usually get in soft drinks.

In HFCS, fructose is nearly 50 percent of its weight, while the fructose in a fresh peach, for example, is only about 1 percent of its weight. The new review also suggests that 100 percent fruit juice, although it technically is not a sugar-sweetened drink, has such high concentrations of fructose that it also provides fuel for the diabetes and obesity epidemics.

Reducing how much fructose you eat without compromising your fruit intake may be the best way to start managing your diabetes if your blood sugar levels are higher than you would like them to be.

These are the main messages of a special article written by a cardiovascular research scientist at Saint Luke’s Mid America Heart Institute in Kansas City, Missouri, and by two M.D. co-authors in a mainstream professional diabetes journal. The results of the study take direct aim at the lax standards of the American Diabetes Association and the 2010 Dietary Guidelines for Americans.

Mayo Clinic Proceedings recently published the study, the full-text of which is online here, “Added Fructose: A Principal Driver of Type 2 Diabetes Mellitus and Its Consequences.”

This mainstream recognition comes as a welcome surprise to me. The recognition of fructose as the most dangerous sugar is no longer just a leading edge theory. I have been warning about its dangers for years, most recently in “Diabetes Without Sugar” about two years ago.

Of course, sucrose and fructose aren’t the only sugars. Glucose, which has a much higher glycemic index, will raise our blood sugar more, but paradoxically it will do much less damage to our bodies. Other sugars, including the lactose in milk are also less dangerous than fructose unless you are lactose intolerant.

Of all the carbohydrates, fructose is the most harmful. Dr. James J. DiNicolantonio, the lead author, says that the overconsumption of fructose deranges both our metabolism and insulin resistance. Several clinical trials have in fact shown that compared with glucose or starch, exchanging equal calories of them with fructose or sucrose leads to higher fasting insulin levels and high fasting glucose levels.

Most people find it hard to understand why fructose is harmful, especially because it has the lowest glycemic index of any sugar. That’s why the food industry can get away with promoting the mistake that agave nectar is good for people with diabetes.

It’s a question of our liver, something that I am especially sensitive to because my wife, who had type 2 diabetes as I do, died from liver failure. Unlike the other sugars, the liver is the only organ in our bodies that can metabolize fructose in significant amounts. Concentrated fructose loads in both human and animal studies decrease the adenosine triphosphate (ATP) content of our liver. Biologists consider ATP “to be the energy currency of life.” Decreased levels of it seem to lead to decreased cellular binding of insulin, a possible reduction in the number of insulin receptors, and subsequent insulin resistance.

Maybe you already knew this and don’t add any sugar at the table. Good for you. But did you realize how much of stuff that we buy at our supermarkets includes added fructose?

In my article about “Diabetes Without Sugar,” you might have noticed a statement that still shocks me. “Three-fourths of all the foods for sale in America have added sweeteners, according to an analysis of 85,451 foods that Dr. Barry Popkin of the University of North Carolina and his team studied.”

My main message is to avoid adding any fructose to what we eat at home. I know that it’s essentially impossible to avoid added sugar when we eat out. But we can manage our sugar at home. We have to stop using the sugar spoon, avoid sugar-sweetened soft drinks, and read the Nutrition Facts labels of all the foods we buy and avoid those that include any of the myriad form of sugar. That’s enough to take a giant step forward in managing diabetes.

This article is based on an earlier version of my article published by HealthCentral.

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  • Reply ashok May 3, 2015 at 10:31 pm

    Dear david and friends,

    I just had my BS done. While fasting is a bit higher at over 6.2, HBA1C is just 3.8 which is on lower side. My fasting sugar has consistently remained high But hba1c remains around 4.5 or so. When i check, after meals, say abt two hrs its mostly around 8. My doctor had advised me about 15 years back to take precaution and since then i get my levels checjed regularly.

    I am male, 49. Wd await yr valuable response.

    ASHOK yadav

    • Reply David Mendosa May 4, 2015 at 8:06 am

      Dear Ashok,

      What is your question? But I have one for you, because you write that your A1C is 3.8 in one place and 4.5 in another. Well, 3.8 is impossible, and 4.5 is as low as anyone has reported it. I just don’t understand your message.

      With metta,

  • Reply Dave V. May 3, 2015 at 9:29 pm

    sorry about that….I didn’t realize that I’d already asked you about that….my confusion/dizziness, etc…hasn’t gone away since I wrote last….it happens after my daily 1-hour walk and when I work in the yard…..or after any activity really…….still trying to figure out what to do….I’m on a low carb diet now, but I see that I should drastically cut back on the fruit I eat…..I’m eating whole grain/lower carb breads, not much, but I’ll cut back on that too…..thanks for your help.

    • Reply David Mendosa May 4, 2015 at 8:08 am

      Dear Dave,

      I wonder if your dizziness could be from an electrolyte imbalance. But if I were you, I would have a doctor check me out.

      With metta,

  • Reply Dave V. May 3, 2015 at 9:21 pm

    Do you agree with Dr. Bernstein who has eaten no fruit for 40 years? I’m new to this and so confused with all the conflicting information from the “experts”…..do you eat fruit yourself? whole grain bread? thanks so much.

    • Reply David Mendosa May 4, 2015 at 8:10 am

      Dear Dave,

      Personally, I eat very little fruit because Dr. Bernstein is right that all of what we think of as fruit is awfully high in carbohydrates. But I do eat a few blueberries a couple of days a week that in large amounts are high carb. I also eat other fruits that aren’t high carb, specifically avocados, lemon, and green peppers, all of which most people don’t think of as fruit, but technically they are.

      With metta,

  • Reply ashok April 5, 2015 at 10:30 am

    Thank uou very much, Marcia.

  • Reply Marcia April 5, 2015 at 9:51 am

    To Ashok,
    I’m not an expert or anything, but from my reading, it seems that juice is best reserved for those who are too ill or unable to eat real food and need an easy infusion of calories and nutrients. If you’re only juicing veggies like spinach and other greens, then perhaps it won’t pack too big a load of sugar. But most palatable juice has a lot of sugar in it. And it has been stripped of its wholeness. It is much more in accordance with nature to eat the whole food and not just a fragment of it.

  • Reply ashok April 5, 2015 at 9:35 am

    Dear David, thank you very much. I am at a loss to decide whether or not to continue with the freshly home made juice.


  • Reply Jane April 5, 2015 at 5:05 am

    Hi. I tried posting this 2 days ago, so if it comes through twice, I apologize. What I wanted to offer is that when I followed Dr. Dean Ornish’s heart diet [pre diabetes], he asserted that eating whole fruits and vegetables had the added benefit of keeping the body feeling full longer, whereas juices do not. It was true for me but it sounds like for many of you that isn’t an issue. I’m attempting to juice some vegetables so I will see if this is something I can do. I am now attempting to learn Dr. Bernstein’s diet and use it with some modification.

  • Reply ashok April 4, 2015 at 3:06 am

    Is home made mix veg n fresh juice okay for type one patients with no added sugar.

    • Reply David Mendosa April 5, 2015 at 9:17 am

      Dear Ashok,

      Sorry, I answered your message yesterday, but apparently my answer didn’t go through. We have to consider three things here: The first is the amount of carbohydrates: your drink is likely to have so many carbs that it will raise your blood sugar awfully high. Dr. Richard K. Bernstein, the leading diabetes doctor, recommends having no more than 6 grams of carbs for breakfast. The second is the fact that it is juicing: many people think that juicing is not a good idea because it breaks down the content of the solid food; personally I haven’t investigated this. The third is the fructose in your drink: about this one, I am not concerned because fructose in fruit is buffered by all the other good stuff, unlike the fructose in table sugar and high-fructose corn syrup.

      With metta,

  • Reply Jane April 3, 2015 at 1:57 pm

    When I choose to eat fruit, I eat it whole/raw. I used to follow Dr. Dean Ornish’s food plan [pre diabetes] in which he emphasized that juices go through the digestive system quicker which leads to feeling hungry sooner. I have found that this is true of me. At my job, a snack of 1/2 an apple or some blueberries fills me up until lunch which isn’t at a regular time due to the nature of my job.

  • Reply Jeff Gauthier April 2, 2015 at 9:12 pm

    I like to have a couple of ounces of high pulp orange juice from the supermarket many mornings. It that hurting me? I also use it sometimes after a long and hard workout, to quench my thirst and bring my sugar up a little. I’m not on insulin, but am on metformin.

    • Reply David Mendosa April 3, 2015 at 11:51 am

      Dear Jeff,

      Good question. I am not at all concerned with the fructose in fruit. But many people who I trust ARE concerned with juicing, which tends to remove much of the fiber. Of course, as you write you are drinking high-pulp OJ, so two ounces of it can’t be too awfully bad for you. Basically, the questions you need to decide is whether your A1C level is low enough and whether your liver is well enough.

      Best regards,


  • Reply Jennifer April 1, 2015 at 8:37 am

    So, what are your thoughts on something like Dr. Pepper 10, a diet drink with does have high fructose corn syrup, but only about a teaspoon. Total carbs+10 Total calories 10 for a 12 ounce soda.

    • Reply David Mendosa April 1, 2015 at 9:28 am

      Dear Jen,

      Personally, I wouldn’t drink it (perhaps because I have never been a big fan of Dr. Pepper!). But I think that any “free” fructose (as opposed to the fructose in fruit) is bad news.

      Best regards,

  • Reply AndreaRN April 1, 2015 at 7:21 am

    I was happy to see that someone finally mentioned that Duke’s mayonnaise was sugar free. I never buy any brand but Duke’s. Trader Joe’s isn’t close enough to make a trip cost effective for me and my husband. My mother used to occasionally make mayonnaise in her powerful old mixmaster. When the blender was invented she was thrilled and so were we…we enjoyed it more frequently. She made the most marvelous mayonnaise with not a grain of sugar…fresh lemons, fresh laid eggs and oil, salt and pepper. Fresh garden grown tomato or cucumber or BLT or even just leaf lettuce sandwiches, often just picked from our back yard. No diabetes then. I am sixty one and don’t take the time to make my own. Honestly, now I try to stay away from mayonnaise and bread altogether…but I do buy Duke’s.
    Thank you, David, for your lovely photographs of birds, flowers and amazing countrysides. I always enjoy your newletter and learn so much from your articles . As a nurse I can share the information along with the joy of nature!

    • Reply David Mendosa April 1, 2015 at 9:56 am

      Dear Andrea,

      Your mother’s mayo sounds absolutely wonderful! But I am with you in avoiding bread, which is one of the very first things that people with diabetes need to realize is harming us.

      I appreciate your comments on my photos! I really try to get people to appreciate nature so we can save it.

      Best regards,

  • Reply Marcia April 1, 2015 at 6:49 am

    The problem with Duke’s mayo and, I think, Trader Joe’s is that they both use either soybean oil or canola oil. Both of these oils, unless organic, are GMO oils. I would recommend staying away from any non-organic products containing either of these oils.

    • Reply David Mendosa April 1, 2015 at 9:43 am

      Dear Marcia,

      Thank you! This is an important point. Soybean oil in particular is the worst offender in the American diet for the fact that most of us have far too much omega-6, which is inflammatory. Canola oil is pretty bad too in that respect.

      Best regards,

  • Reply Doug Weathers March 31, 2015 at 10:58 pm

    Hi, another vote for Trader Joe’s mayonnaise from me. It’s delicious.

    I am surprised that agave “nectar” has fructose in it. Thanks for the tip!

    • Reply David Mendosa April 1, 2015 at 9:50 am

      Dear Doug,

      Agave has long been advertised as being healthy for people with diabetes simply because it has a very low glycemic index. But that is entirely because fructose is the low GI sugar. There is more to managing diabetes than being low-glycemic, and the biggest thing we need to know is the dangers of fructose.

      Best regards,

  • Reply marianne March 31, 2015 at 8:11 pm

    Thanks all of you. I live in Canada so no Trader Joe’s or Dukes.

  • Reply Merry693 March 31, 2015 at 8:02 pm

    Duke’s Mayonnaise is sugar free. http://www.dukesmayonnaise.com/our-products.asp?id=2

    Google “sugar free mayonaisse” and find some you can make yourself.

  • Reply MN March 31, 2015 at 7:27 pm

    Thank you for this simple and clear explanation of the problems with fructose- it clears up an issue which has puzzled us for some time!

    My husband is diabetic, and since generally, the less processed, the better for his diet, I didn’t understand why honey was so elevating to his blood sugar, but other sweeteners (in moderation) were fine. Honey is the least processed and most natural sweetener there is, right?

    I know honey is high in fructose, but I didn’t understand why that was a problem- until your great explanation. I will read this article to him over breakfast tomorrow!

  • Reply jacqueline March 31, 2015 at 6:58 pm

    My favorite mayo is Trader Joe’s Real Mayo (not the light version). No preservatives, no added sugar and almost as good as homemade.

    Hope this helps.

  • Reply k v rao March 31, 2015 at 6:52 pm

    can we consume large quantities of fruits or we should put constraints over food consumption too for normal persons, not diabetics per se. Please comment and advise.

    • Reply David Mendosa March 31, 2015 at 8:11 pm

      The problem with fruit isn’t the fructose that it has because it is buffered with fiber and other macronutrients. The problem is the high amount of carbs that most fruits have.

      Best regards,

  • Reply Roberto March 31, 2015 at 1:52 pm

    David, good afternoon. The average consumption of soft drinks in Mexico is 3-4 liters per day and my government does not care. Diabetes in my country reached pandemic levels. Very good your news comes here and will do my best to spread among the people the terrible tragedy that causes fructose corn. Thanks for spreading your research.

    • Reply David Mendosa March 31, 2015 at 2:34 pm

      Dear Roberto,

      I read recently that Mexico is ahead of the United States! That would be marvelous except Mexico leads in being even fatter than we are now. Of all the world’s major countries Mexico is Numero Uno! The soft drinks that you write about may well have something to do with this leadership.

      Best regards,

  • Reply Dave V. March 31, 2015 at 8:02 am

    I’ve been trying to figure out why I’m lightheaded/faint/dizzy/confused…my Ac1 is pre-diabetic…I’ve lost 30 lb since Sept. I walk an hour daily. Dr. says drink more H2O…Nurse said take Dramamine….nothing’s changed…..thanks so much for the fructose update – I’ll start checking…btw, my diet is low carb, but I’ll start checking fructose.

    • Reply David Mendosa March 31, 2015 at 9:03 am

      Dear Dave,

      I once looked up all the things that can cause us to get lightheaded. There are dozens of reasons! I know that when we go on a very low-carb diet that can happen — but only for the first few weeks. I have also experienced it when my electrolytes were out of balance, and I wrote about what I use for that now: http://www.mendosa.com/blog/?p=1166

      Best regards,

  • Reply Roger March 31, 2015 at 6:16 am

    In case you haven’t checked out Dr. Jason Fung I think you will find him very interesting

    • Reply David Mendosa March 31, 2015 at 9:33 am

      Dear Roger,

      Thank you. Many people will find him as interesting as you and I have. He is far too little known!

      Best regards,

  • Reply Roger March 31, 2015 at 6:14 am

    David- take a look at Diet Doctor- there is a recipe for homemade mayo there using a stick blender that is incredibly easy- I suggest buying pasteurized eggs for safety purposes

  • Reply Robert March 30, 2015 at 6:05 pm

    I read labels all the time, but I just read an article that the companies have found a way around the labels in that they change the portion size so they do not have to report certain items, thus you read the label and think you are ok but in truth due to the real amount, you are not!! I love your articles. I’m constantly telling my military doctors about you…hope you don’t mind.

    • Reply David Mendosa March 30, 2015 at 8:11 pm

      Dear Robert,

      The trick you write about is used most notoriously with trans fats. With it (and any other item that has to be listed on the Nutrition Facts label) if the declared serving size is less than one-half of a gram, they can of course round it to zero. But you can catch them at it with trans fats because they also have to declare the ingredients. If they list partially hydrogenated oil, you know that it does have some trans fat.

      Best regards,

  • Reply Mark March 30, 2015 at 4:43 pm

    I’m a bit concerned that the article implies fruit is ok, but as a diabetic, I know I have to eat fruit in very limited quantities, usually a 1/4 cup of blueberries,raspberries,blackberries, etc. Forget the bananas,pineapple,etc.


    • Reply David Mendosa March 30, 2015 at 5:22 pm

      Dear Mark,

      Good point. Two things are at work here: fructose and total carbs. All the experts say that the fructose in fruit is not to be concerned about. But anyone who knows about diabetes and very low-carb diets knows that fruit, particularly the tropical fruit like bananas and pineapple and mango, is awfully high in carbohydrate. I personally almost neer eat any fruit except blueberries and, like you, in very small amounts.

      With metta,

  • Reply marianne March 30, 2015 at 4:20 pm

    I just threw out an entire jar of low-fat mayonnaise because it contained so much sugar and even tasted way too sweet. But when I shopped for regular mayonnaise, I couldn’t find any brand among about 10, even the overpriced “organic,” “natural” ones without added sugar.

    Do we have to make everything from scratch? Who has the time?

    • Reply David Mendosa March 30, 2015 at 4:29 pm

      Dear Marianne,

      Like you, I don’t know of any store-bought mayonnaise that doesn’t have some form of sucrose (which is half fructose) or fructose in it. Maybe someone else can tell us. And I certainly don’t have the time to make it from scratch either. I used to love mayo on lots of food, particularly on artichokes. Nowadays I use melted butter or ghee.

      With metta,

    • Reply David Mendosa March 31, 2015 at 9:38 am

      Dear Marianne,

      I want to make sure that you saw the recipe for simple mayonnaise that Roger just brought to our attention. The recipe is at:

      Best regards,

  • Reply Jane March 2, 2015 at 3:07 am

    I’m still having a hard time putting the information into my mind so that I can understand how the chemistry works. However, I’ve understood for a few years that the food industry permeates our food with sugar. I just bought what I thought were plain peanuts & didn’t read the label. Yup, they added sugar to them! Darn.

    • Reply David Mendosa March 2, 2015 at 2:09 pm

      Dear Jane,

      Like you, I am still amazed at the amount of our supposed healthy food that has added sugar. We absolutely have to make it a practice of reading the Nutrition Facts label of every food we buy. That’s hard and I sometimes slip up too!

      With metta,

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