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Diabetes Complications, Diabetes Diet

More Trouble with Fructose

We knew that the trouble with fructose is how hard it hits our the liver and how much it raises our triglyceride levels, which increases our risks for heart attacks. High-fructose diets also lead us to secrete more insulin, which in turn leads to more insulin resistance.

Now we are learning that this deceptively low-glycemic sweetener can cause even more trouble. The trouble with fructose isn’t just insulin resistance and heart attacks, as serious as they are. And it’s not even just because of the massive amounts of high-fructose corn syrup that most people in the developed world added to their diets in the past 30 years or so.

The trouble is with fructose comes from even much smaller amounts. Even from the fructose in most fruit and in some vegetables.

I used to write off those relatively small amounts of fructose. Two years ago I argued here that what I considered the trivial amounts of fructose in food don’t matter. The experts, like Dr. John Bantle, a professor of medicine in the division of endocrinology and diabetes at the University of Minnesota, told me so.

But we were overlooking research that shows that even these supposedly trivial amounts of fructose didn’t matter. After all, the experts in the American medical establishment have been telling us for years that we need our daily servings.

The key study came out in an obscure professional journal six years ago. But I missed it until Dr. Michael Eades brought it to my attention. Dr. Eades, who with his wife Dr. Mary Dan Eades, wrote one of the low-carb bibles, Protein Power, as well as another half dozen books, also has one of the best wellness blogs, “Health & Nutrition.”

His recent article, “Vegetarians AGE Faster,” shows that vegetarians have significantly higher rates of advanced glycation end products (AGE) than do omnivores. It’s not just a coincidence that the acronym for advanced glycation end products is AGE. As our bodies accumulate more and more glycated proteins, our bodies do grow older than our chronological years.

Glycated proteins in our bodies are simply proteins attached to sugars, but they don’t work well there. I have tried to expose the problems with AGEs for years, and back in 2002 I first wrote about the trouble with AGEs for my “Diabetes Update” newsletter. More recently I wrote here about AGEs in May 2006, in June 2006, in September 2006, and in April 2007. But until now I failed to appreciate that natural fructose could be one of the devils in the AGE details.

The obscure study that Dr. Eades found finally convinced me that we need to limit not only high fructose corn syrup and other artificial fructose but also the naturally occurring fructose. My friend Joe Anderson has been arguing this case for years. But I thought that he was going too far.

He wasn’t. I wasn’t going far enough.

The researchers studied 19 vegetarian and 19 omnivore subjects recruited from the region around Bratislava, Slovak Republic. Three of the researchers worked at the Institute of Preventive and Clinical Medicine in Bratislava. One of them worked at the Institute of Physiological Chemistry of the University of Würzburg in Würzburg, Germany, where I happened to have studied for a year.

The omnivores actually ate a higher carb diet than the vegetarians and cooked their food at higher temperatures than the vegetarians did. But the vegetarians ate more fruits and vegetables, giving them significantly more fructose in their diet. The researchers found that the vegetarians had significantly more AGEs.

The research report, “Advanced Glycation End Products and Nutrition,” by M. Krajčovičová-Kudlačková, K. Šebeková, R. Schinzel, and J. Klvanová, appeared in the journal Physiological Research. The full-text of the article is online.

But even if you accept that natural fructose can cause the formation of AGEs, as I do now, we still have a big problem. How much fructose is too much? The authors of this research report don’t say.

So I turned back to Joe Anderson, who until now has been a voice in the wilderness of fructose. By email he tells me that his recommendation, based in part on Nancy Appleton’s book, Lick the Sugar Habit (Avery, second edition, 1996),  is to eat no more than 4 grams of fructose per day. In practice he doesn’t eat fruit that provides more than 2 grams of fructose per serving.

“That isn’t much fruit!” Joe exclaims. “We were not evolved to eat much fruit! Modern fruit have been bred for high sugar content, among other things. Older fruit varieties are less sweet and succulent. Proto-fruits were typically sour or nearly so. Think crab apples vs. Fujis.”

This prompted me to search the USDA National Nutrient Database, which is online. But that’s a slow way to search for a lot of different foods. Fortunately, the USDA also makes in available to download to your computer — if you have a Windows PC or PDA instead of a Mac. That’s one of the few reasons why I kept my old PC when I got my first Mac four years ago.

So, arbitrarily defining a serving as one cup, do all fruit servings have more than 2 grams? Fortunately not.

But before we can pinpoint which are the good fruits, we still have a couple tricky things to keep in mind. The first is that the dividing line between what we call a fruit and a vegetable is different botanically than it is gastronomically. What this means for present purposes is that we also need to consider the fructose in the vegetables that we eat.

The second tricky thing to remember when we search the USDA’s tables for fructose is that they show only the fructose as such. We need to remember to add half of its sucrose, because sucrose is half fructose and half glucose.

Still, several fruits are low in fructose, both as such and as sucrose. Avocados are the outstanding example. Their low fructose content is one more reason why avocados have become a regular part of my diet.

Lemons and limes are also low in fructose. But not their cousins oranges and grapefruit.

Sweet green peppers are indeed a fruit botanically. And they are a good fruit too in terms of their low fructose level.

Sadly, one of my favorite fruits, tomatoes, barely missed making the cut. A cup of a raw tomato has 2.5 grams of fructose.

Not long ago I wrote here about the “Good Veggies.” But in light of what I now know about fructose not all of them are all that good.

Most of those “good veggies” really are good for us. But carrots have too much fructose for us to think of them any more as being good for us. “Carrots are fructose sticks,” Joe says.

The other formerly good veggie is the botanical fruit, sweet red pepper. Unlike sweet green peppers, the red ones are high in fructose.

Not listed among the good veggies but relevant to this discussion are Jerusalem artichokes (also known nowadays as sunchokes). By whatever name you know them, they are bigger fructose sticks than carrots are.

Onions too have more fructose than is good for us. “One of the most disappointing days in my life was when I learned how high in fructose that onions are,” Joe wrote me. They actually have about 2.6 grams of fructose per cup. “I miss them, but will occasionally use small amounts of them as a condiment.”

That’s the way to think about those fruits and vegetables that are a little too high in their levels of fructose. And remember that we still have a lot of wonderful foods to chose from. Particularly if we are omnivores.

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

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  • f-s at

    oh, and source I wanted to share with my above comment about carrots having 1g per 100g serving, as can be seen in this article and list: http://www.foodintolerances.org/fructose-food-table.aspx

  • f-s at

    I have HFI and carrots do not seem to affect me. And saying “carrots have too much fructose” that is a statement based off of what? Because the fructose content for raw carrots in 100g serving I have found to be 1 gram of fructose….why say this?

  • peter lemer at

    Henry, I can see what you mean but David said ” carrots have too much fructose for us to think of them any more as being good for us”, and seeing as he da man, I have to ask for clarity 🙂

  • David Mendosa at

    Dear Peter and Henry,

    The message that Henry left a year ago, Peter, is a big help. He wrote in part:

    There is a much more convenient online database for sugar data:
    This is much faster to use than the USDA site as you mentioned.

    This site, and any other that is worth considering, is based on the USDA site, which is the gold standard.

  • Henry at

    Hi Peter,
    Please note that fructose is only one sugar in a food. Raw carrot has .55 g of fructose per 100 g of weight, but it also has .59 g of glucose AND 3.59 g of sucrose.
    David most likely refers to total sugar, not just fructose. And total sugar can include lactose, maltose, galactose in addition to fructose, sucrose, glucose.
    For total sugar content of foods, you can google ‘sugar counter’.

  • peter lemer at

    Confusion reigns! 🙁
    David quotes that carrots are ‘sugar on a stick’ , onions are high in fructose, and somewhere I read that raspberries are good, yet Henry’s link shows carrots: 0.55
    onions: 1.44
    rasberries: 2.35
    how do I design a low-fructose diet when various sources give different values?
    I’ve reduced carrots, onions, apples, pears, and upped raspberries, apricots, cantaloupe and so on, based on an early understanding of fructose levels, but the signal/noise ratio seems a tad high. Any suggestions? – pete

  • robito at

    Hi David Thanks for the great article! I have a question which might be obvious but nevertheless… I downloaded the USDA National Nutrient Database which is great but I don’t see fructose content in the nutritional breakdown or should I be looking at something else? If I look at oranges for example, I don’t see fructose or sucrose in the table list? Please help! Thanks


    • David Mendosa at

      Dear Robito,

      Good question. It’s there but not obvious. From the “basic report” that comes up when you search on a specific food, go to “full report (all nutrients).”



  • Henry at

    Hi David,
    There is a much more convenient online database for sugar data:
    This is much faster to use than the USDA site as you mentioned.
    They also have some good GI and GL database there, I think.

    • David Mendosa at

      Dear Henry,

      This is a great resource! Thank you for sharing your knowledge about it.



  • sadaf at

    dear David
    i would like to know your opinion about moringa leaf powder for lowering bglevels and other healhty effects. locally this is called sonjhana in subcontinent. i have just started using it as one teaspoon early i the day before breakfast along with oral medication.
    your opinion matters to me so please do find out

    • David Mendosa at

      Dear Sadaf,

      I have heard very little about moringa. Two studies seem to show that it can reduce blood sugar:


      In addition, several studies of moringa in rats also seem to show that. But I don’t think that it is wise to rely on supplements like this to control diabetes. They aren’t tested or standardized. Besides, the only sure way to control diabetes without the side effects of drugs — and supplements ARE drugs — is to reduce the amount of calories we get from sugars and starches.



  • Arun Prabhu at

    Though I am strictly not a vegetarian, I am veggie for most part. I have drastically curtailed grains, completely avoid added sugars and have eliminated sweets entirely. As a result I have lost close to 40 lbs (BMI 20.5) and my a1c is down from 6.8 to 5.3 without any medication.
    Here I would like to add that I eat 3-4 small portions of fruits daily including bananas, oranges and apples. As for triglycerides it is down from 185 to 60 in July this month.

    Possibly humans are a complex breed to come to a definitive conclusion on how each one will react to foods.

  • Reason at

    It is wrong to jump to the assumption that it was the fructose in those vegetarians’ diets that led to higher measurements of advanced glycation end products in their bodies.

    There were a multitude of unknown and unmeasured dietary and other variables which may have potentially led to this difference between the vegetarians and omnivores.

    Just to give two examples: both carnosine and taurine inhibit glycation, and these two substances are very low or completely absent in most vegetarian diets – unlike in omnivorous diets.

    AGEs can also be ingested directly(rather than formed within the body after ingestion of fructose or from high blood glucose levels.) With few exceptions, fruit has amongst the lowest inherent AGE content of any foods. Funnily enough, avocado which is mentioned in the article as being particularly low in fructose and thus supposedly desirable, actually has one of the highest levels of AGEs of any fruit(as do many other foods with high fat content.) See Helen Vlassara’s work for more on this.

    As for vegetarian/veganism and diabetes(which this site has a focus on); the best data currently available shows that these groups have only half to one third the rate of diabetes compared to the omnivorous population:

  • etagron at

    Barnando LaPallo is 109 years old and healthy and claims to have only ever eaten fruit, juices & vegetables – that’s a fairly regular amount of fructose daily for over 100years. Look him up on Youtube

  • saddaf sultana at

    eid mubarak . May all umn beings live in peace and be happy together. ameen

    yesterday someone commented about my receding hairs and mentioned it as an outcome of diabetes. it got me worried. if i am not on medication and maintaining A1C at 6. to 7., does that mean severe hair loss is becuase of this where as my eyesight remains at o.5 for reading or sewing. i donot frequent washroom nor i do suffer from knee trouble anymore which i used to have one year back. i can do light climbing ( 3,000 feet high mountains take 3 hours to climb up) and trekking as well which we do three four times a year as excursion.

    why should hair loss be linked to controlled diabetes. i know i should take the a1c down to 5. but still . how can i be sure and is there any remedy. i heard about taking fishoil capsules.

  • David Mendosa at

    Dear Saddaf,

    That’s a good point. My guess is that the brand of sucralose that you get in Pakistan has about the same amount as the brand of it, Splenda, that we get here. It does add some calories and some carbs, but doesn’t concern me much. They add it as a filler so the amount of sucralose we use is easier to measure. Nevertheless, I prefer stevia, which I am able to get here that uses inulin (a fiber) as a filler. But I use sucralose when it’s the only thing available.

    Best regards,


  • saddaf sultana at

    hello david and thanks everyone.
    our fast from dawn to dusk is almost 14 hours long now a days here in pakistan. we donot drink or eat anything in between. great body cleansing exerise if junk food is avoided and less is eaten.
    i take sucralose branded as sucral and add i teaspoon per serving of hoemade yogurt that satisfies my sweet tooth. this i take twice a day to wardoff some of the acidic affects of eating green chillies regularly. what worries me is he amont of maltodextrin in sucral. its percentage by weight is not mentioned and i am afraid it is not really as trouble free for diabetic as is advertised. any information will help.

    my cavings for sweetnes started only with the diabetes. before that, i could not stand any sweets except occasional chocolates and icecreams.


  • Mary at

    Thanks David,

    I will get myself to the Doctor in the morning as the fever is back this afternoon.



  • David Mendosa at

    Dear Mary,

    I don’t know about any supplement for that. Sorry.


  • Mary at

    Hi Saddaf,

    Here is a link to the one I use. There are 8 little tubs in a box and each tub makes 1/2 gallon (2 liters) this is also sold online and it says zero carb but it does have 5 calories, so be careful. It tastes exactly like apple juice to me.


  • Mary at

    Hi Saddaf,

    I forgot to mention, I drink a wonderful apple drink mix that contains 100% of the day’s need for vitamin C and is sugar free. I buy Walmart’s Great Value brand because it is cheaper to buy this store brand. But that is a copy of a major brand (probably the same stuff) and it is made by Crystal Light. Maybe a store where you are carries this product? If not they sell it online also. Below is an online link I found for you.


    I hope this is helpful for you.


  • Mary at

    Hi Saddaf,

    It will help if you keep your belly full of water! Drink as much water as you can, because sometimes cravings are caused by dehydration and we are not aware that is the problem! Also the Lemonade is definitely better than water but water is usually closer. So when you can not have the lemonade, drink water, water, water!

    Good luck,


    PS: David either I have a UTI in addition to, OR my mild case of food poisoning was a UTI. I will have to go to the doctor I think, because this does not usually get well without antibiotics and there is blood in the urine. Do you know any OTC or supplements that help this problem? I have them fairly often.

  • saddaf at

    dear david

    what a hustling bustling forum you have created for us. thanks .
    it is fasting month ramazan for us and i have been fasting. i am just worried about half a glass of apple juice that i take at dinner when i break the fast. it is hot and humid here and i just want to drink a lot of cold and sweet juice. any suggestions on how to avoid this craving?

    • David Mendosa at

      Dear Saddaf,

      My guess is that you crave sweetness. I think that fasting is awfully helpful, although I haven’t started yet (maybe you can give me some tips based on your experience). But if I were in your shoes I would drink something like lemonade made with stevia. If you can’t get stevia where you are, I would get another no-calorie sweetener like Splenda.

      Best regards,


  • Mary at

    Hi Rishi,

    Have you looked at Dr. Bernstein’s Diabetes Solution Diet? It includes Vegetarian alternatives I believe and it is extremely low carb also. Here is a link where you can read part of the book online for free.

    My blood sugar dropped like a rock as soon as I started this diet and I had to get off my Glyburide right away because it was no longer needed! My weight also is dropping very quickly.

    http://diabetes-book.com/ when you get to this site, just click the tab that says Read it Online. You will get a free (fairly detailed) look at the diet from this site and can decide if it would be good for you.

  • Rishi at

    Hi David,

    Being a vegetarian, who is trying hard to find the right low-card diet, I find your website most useful.
    Do you think Apples are bad too? In terms of high fructose content.
    Do you a longer list of good fruits?

    • David Mendosa at

      Dear Rishi,

      I’m not concerned with the small amount of fructose in apples. But I rarely eat one in order to stay on my low-carb eating plan.


  • Molly B. at

    Do you know how many times I’ve read that grapefruit is a LOW fructose fruit?

    Thank you for the tip.

    Also, I’ve read that people who can’t eat onions or garlic frequently can eat SHALLOTS – it said that shallots don’t have the fructans of the other too.

    • David Mendosa at

      Dear Molly,

      Yes. Dr. Bernstein recommends shallots over onions.


  • Matthew at

    Hi David,
    I was just wondering whether your health has improved since you limited fructose in your diet.

    It seems counter intuitive to limit fruit in ones diet.

    • David Mendosa at

      Dear Matthew,

      Thanks for asking. Yes, my health has been better than ever. My A1C and BMI are lower than ever. And my liver — which fructose impacts negatively — tests normal now.

      Best regards,


  • Kevin Fitzpatrick at


    It’s been a year since you wrote this article, and a new study came out just this week.

    I just read this article today:

    The study doesn’t even address the issues with the liver, elevated triglycerides, or AGE formation. But it DOES give us yet another reason to avoid fructose.