Not All Sugars are Equal

A quick hit on an interesting bit of new research, published in the Journal of Clinical Investigation.

Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans

Studies in animals have documented that, compared with glucose, dietary fructose induces dyslipidemia and insulin resistance. To assess the relative effects of these dietary sugars during sustained consumption in humans, overweight and obese subjects consumed glucose- or fructose-sweetened beverages providing 25% of energy requirements for 10 weeks. Although both groups exhibited similar weight gain during the intervention, visceral adipose volume was significantly increased only in subjects consuming fructose. Fasting plasma triglyceride concentrations increased by approximately 10% during 10 weeks of glucose consumption but not after fructose consumption. In contrast, hepatic de novo lipogenesis (DNL) [RN: liver making fat] and the 23-hour postprandial triglyceride AUC were increased specifically during fructose consumption. Similarly, markers of altered lipid metabolism and lipoprotein remodeling, including fasting apoB, LDL, small dense LDL, oxidized LDL, and postprandial concentrations of remnant-like particle–triglyceride and –cholesterol significantly increased during fructose but not glucose consumption. In addition, fasting plasma glucose and insulin levels increased and insulin sensitivity decreased in subjects consuming fructose but not in those consuming glucose. These data suggest that dietary fructose specifically increases DNL, promotes dyslipidemia, decreases insulin sensitivity, and increases visceral adiposity in overweight/obese adults.

Wow, that's quite an indictment, as well as a contrast. So, fructose makes your liver create new fat, gives you more small dense LDL and oxidized LDL — the worst, true artery "clogging" kind — and gives you a fat belly.

Think about that next time you purchase products that contain HFCS, which just about all processed food does.

It's useful to note that primitive man in most environments would probably have had quite a bit more access to higher glucose concentrations (tubers and such) than fructose (fruits, honey, and so on) most of the time. It could be that we specifically evolved to put on fat in the late summer and fall in preparation for winter, and that fruit was a primary vehicle for accomplishing that.

Perhaps potatoes aren't as bad as thought, and maybe fruit isn't as good. I like to limit both, but if I had to choose, I'll take some potato with my meat.

Later: Hadn't seen this yet, but Stephan blogged about this study.

Richard Nikoley

I'm Richard Nikoley. Free The Animal began in 2003 and as of 2021, contains 5,000 posts. I blog what I wish...from health, diet, and food to travel and lifestyle; to politics, social antagonism, expat-living location and time independent—while you sleep—income. I celebrate the audacity and hubris to live by your own exclusive authority and take your own chances. Read More


  1. minneapolis J on April 24, 2009 at 17:52

    Richard, good study man. However, this study isnt necessarily implying that fruit is bad in my opinion. The reason why is that only some of the sugars in fruit are fructose. Also fructose usually causes a problem when it is concentrated. For example high fructose corn syrup is very concentrated. also like sweetened fruit snacks….are very concentrated.

    interesting argument about potatoes, you know I have heard more and more about how potatoes are not that bad as starch. Is that the vibe you are getting too?

  2. Katelyn on April 24, 2009 at 12:48

    I would avoid potatoes and fruit like the plague. Just eat delicious, fatty meat, Richard! I know you love meat and butter and eggs!

  3. marianne on April 24, 2009 at 23:46

    There is a brilliant book by David Gillespie called SWEET POISON.
    M x

  4. Richard Nikoley on April 24, 2009 at 19:32


    Yep. I agree about concentrate. As a general priciple, we ought to be avoiding all concentrates, except perhaps olive oil.

    Jury still out on potato, but intermittency renders the question essentially moot.

    Richard Nikoley

  5. John Nugent on April 25, 2009 at 05:32


    More brilliant science to work with – and thanks for all your work in this area. I await with interest your further feedback.

    I have been left with belly fat and fat around my chest. Can't get rid of it. There are times when I feel like eating only vegeatbles and when I feel like eating only proetin (steak, pork, seafood etc). Maybe that is my system telling me what it needs.

    Best wishes

  6. Skyler Tanner on April 25, 2009 at 05:36

    25% of calories from fructose is a staggering amount that I think very few people who were *truly* interested in improving their health would see anything close to that amount of fructose.

    The notion that fruit is, at best "not bad" for you, and at worst truly awful is an unfortunate conclusion reached by exaggerating the results of studies like this.

  7. Richard Nikoley on April 25, 2009 at 09:14

    I'm on the fence about it, frankly. I just know that for myself, I seem to do better with very minimal bits of it, mostly berries, some grapes, a bit of melon.

    Interestingly, the only time I seem to get heartburn anymore is when I include fruit with breakfast. Of course, this is what holds for me.

    If I wanted to mimic my likely northern Euro ancestry, then I'd gorge on as much fruit as I could in the late summer and early fall, and then have none at all the rest of the year. Wonder how much weight I'd put on in advance of winter? I don't think I want to try. 🙂

  8. Richard Nikoley on April 25, 2009 at 09:15

    Listen to your own body first.

  9. Richard Nikoley on April 25, 2009 at 11:58

    Yes I do. But, I also like a bit of cheese now and then, some nuts, and some veggies, particularly in things like my curries, stews, chilis, stir frys (in CO) and so on. And, some berries now and then are cool.

    It's probably a rare day I eat that many carbs, but then it's been a while since I have thought carbs are the primary problem. I think the primary problem is flour, sugar, and vegetable oils.

    I think it's perfectly possible to live a healthful life from equator to arctic circle, eating of all the foods nature provides, regardless of carbs. That said, as someone of norther Euro ancestry, I am definitely heavily weighted to the more carnivorous side.

  10. Name Taddy on April 27, 2009 at 11:19

    Has anyone out there tried Quinoa as an alternative to a starchy potatoe? It was used by the acient Incas. I have included a website for you to research on it. You will be surprised has to the great benefit is has. Taddy

  11. Richard Nikoley on April 27, 2009 at 12:02

    Hi Taddy:

    I don't have a big problem with Quinoa. I don't eat it currently but would not rule out having it sometimes. Rather than toxins — gluten and other lectins — being the problem, it's pretty high in carbs, so that would be my main consideration.

    Mark Sisson has a post on Quinoa:

    And here's another of his posts on grains:

  12. Carey Moore on May 5, 2010 at 07:14

    Ugh, yes. This is why the “well, I want to eat healthier so I sweeten my foods with agave syrup” phenomenon scares me. Agave syrup is much higher fructose than even most commercially-used HFCS. It induces less glycemic response because all that fructose has to be processed through the liver (like alcohol), causing fat production, insulin resistance, and in the long term, cirrhosis.

    I avoid most fruit now as a general rule, and when I do indulge, it’s in lower-fructose avocado, citrus, and pitted fruit like apricots and peaches, but not fructose-heavy apples, grapes, and pears. I love this chart I found:

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