The Bitter Truth About Sugar

A picture of The Bitter Truth About SugarI want to tell you about something pretty amazing.

It is a YouTube video of a lecture, by the endocrinologist Robert H. Lustig, M.D., who is a professor at the University of San Francisco.

In the video, he explains how sugar, and fructose in particular, may be to blame for a large part of the health problems that western populations face today.

These include high blood pressure, insulin resistance, obesity, dyslipidemia, pretty much all of the things we recognize as the metabolic syndrome.

I’ve been doing some research on the claims he makes in the lecture, and they all seem to be true.

When carefully examining the metabolism of fructose, it turns out that it:

  • Increases uric acid levels, leading to hypertension (high blood pressure) and gout.
  • Makes your liver synthesize fats, which are sent to the bloodstream as VLDL particles, leading to dyslipidemia (cholesterol, triglycerides) and heart disease.
  • Causes insulin resistance in the body’s tissues, which leads to hyperinsulinemia.
  • Increases fat deposition in the liver.
  • How fructose doesn’t reduce the hunger hormone ghrelin, and how it doesn’t affect the hormones insulin and leptin, which are one of the body’s signals to tell the brain to stop eating.

The video is one and a half hours, but Robert H. Lustig honestly is one of the best lecturers I’ve seen and this video is about as entertaining as a movie in my opinion. I’ve watched it three times.

If you are interested in educating yourself on health and nutrition, then I highly recommend you check out the video.

I’d like to point out that fruits do contain fructose, but the amount is very tiny compared to what you get if you eat a lot of sugar.

The implications of this is to avoid added sugar, high fructose corn syrup, fruit juices and dried fruit. Eating a few pieces of fresh fruit per day is fine, as the carb and fructose content in them is small.

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  1. The same could be said for wheat and Dr. William Davis says that he believes wheat may even be worse than sugar. Check out his blog… Pretty eye opening stuff!

    • i was just going to say that about wheat! the book wheat belly is an eye opener. i wish someone would do a combined refined sugar/wheat study and write up.

  2. Low carb or High carb…when you look at long lived populations it seems the common thread is low/no sugar and avoiding processed foods.

  3. Thankfully, there are alternatives to sugar which are almost as good (stevia, i’m looking at you).

    It’s only for those times when its absolutely necessary will I succumb to it.

    All that aside, the sugar in my red wine is going to have to stay right where it is :)

  4. Kris,

    I’m with Clint on this one… big fan of Stevia.


  5. Kimberly B. says:

    WOW. Awesome video kris thanks for putting this on your blog. I’ve read about high fructose corn syrup being bad but seeing how it’s metabolized and listening to why our government isn’t doing anything to regulate this is sad. I can’t believe that it’s in formula for babies! I try to follow a paleo diet for the most part and this gives me all the more reason to stick to eating things that do not come from a box.

  6. Julius Juliusson says:

    Hi Kristjan. I would just thank you for all your help :)

  7. Philippa says:

    I have read about the dangers of sugar in many places (as well as the dangers of fat).
    One thing I wonder about is whether there is something particularly bad about the combination of fat & sugar?
    There are societies that consume lots of fat that don’t have many problems. Is it the combination of fat and sugar that is particularly damaging or is it sugar that is the real problem?

    • There are good carbs and bad carbs, as well as good fats and bad fats. Combining bad carbs with bad fats is a recipe for disaster.

      Most foods that are both high in sugar and fat are junk foods anyway.

  8. Tricia Felty says:

    Hi Kris,
    I’m really enjoying your blog. I’ve personally reduced my carbs to around 50-75 per day. I’ve started losing weight again…. I’d been stuck for a year or so. It’s been about 6 weeks since I started watching carbs and my only complaint is a lack of stamina in my workouts. I was hoping that would resolve but it hasn’t. My favorite exercise is jogging, but I’m really struggling to last more than 20 min or so right now. Is this normal? Any advice?

    • This is completely natural. Your muscles don’t carry as much glycogen when you eat low-carb which means that you won’t have as much energy when you’re doing intense workouts.

      I recommend you eat some more healthy carbs around your workout, such as some oats, rice or potatoes in the morning or a few hours before. About 50 extra grams of starchy carbs for each session might do the trick.

      • I wonder if the time of running would also be a factor here?

        I find that I can do cardio (within limits) more easily when I do it first thing, if I’m low-carbing. It seems that the daily activity burns through carb stores (when you’re not keto adapted at any rate) and trying to exercise in the evening comes when you’re at your lowest stores…

  9. This is truly amazing. I am crying as I watch this. I feel such a fool. I had a gastric sleeve operation to lose 10 stone and still have 4 to go. I will no longer be fooled by these awful people who only have money on their minds.

    • You are definitely not a fool and I’m sure most health professionals really have the patients best interest in mind, even though they are often misinformed about nutrition.

      I am not entirely against weight loss surgeries, but they should definitely be considered a last resort in my opinion.

  10. Hi Kris,

    Do you have any idea if the host of co-factors that come along with the fructose in solid, real fruit negate the negative effects of fructose in the liver?

    My bet is they do, but I’ve never looked into it…

    Keep up the good work,

    • Dr. Lustig believes that the fiber in fruit helps negate the negative effects of the sugar.

      Myself, I think it’s a volume issue. The amount you get from sugary treats is soooo much more than you get from 2-3 pieces of fruit every day.

      • I can see the virtue of both points.

        The fibre would slow down the rate of digestion to a level that the liver would find acceptable, and having significantly lower amounts of the sugar in total will have a similar effect.


  11. Anti Juice Mom says:

    Thanks Kris for sharing this video. I never gave juice to my kids, and this video just confirmed my belief. I had never been able to understand difference between Glucose, Fructose, Sucrose and HFCS but this lecture provided me that clarity.

    I think knowledge is power and once the parents understand what they have been letting kids gulp, they will change the habit. (so we hope)

  12. I’ve just finished watching the video. Taken me several visits to get through it, and I’ll need to go through it again, so I’ll keep coming back to this article. Excellent video though. I did not realise glucose and fructose were metabolised in such different ways. He mentions lactose is ok, but doesn’t go into that. Do you know anything about how lactose is metabolised?

    • Lactose gets broken down into Glucose and Galactose in the digestive tract by the enzyme Lactase.

      Lactose Intolerance = Deficiency in the enzyme Lactase.

      After Galactose is absorbed, it is turned into Glucose and from there goes through the same pathways.

      Only problem I know of is lactose intolerance, which is pretty common in many parts of the world.

      • Am I right in thinking that lactose has almost the same insulin response as glucose?

        If it does, that would indicate that where there’s no lactase deficicency digestion is extremely fast and pretty efficient…


        • Kristjan says:

          Not quite sure how galactose affects the beta cells of the pancreas, the cells that produce insulin.

          But dairy foods seem to be pretty high on the insulin index, perhaps that means galactose is equivalent to glucose. If you find the answer then please let me know.

  13. Steve Taylor says:

    Hi Kris
    I have got to say I really like the information you post up. To be honest I was like many not loosing weight but trying to eat less. I know now I was generally eating the wrong type of food. Consequently nothing happened. I thought I would give the Dukan diet a go which in the early stages is totally protein then later kicking in vegetables/Carbs etc. I lost 12 pounds in about 6 weeks which was great.
    I have followed your recent advice about your workouts and the results for you look great. I go to the gym twice a week for about an hour and swim 30 lengths twice a week so although I’m not a gym freak I’m no couch potato either. I am 57 by the way.
    I’d like to loose a bit more weight and even though I follow your advise on a low carb, no wheat diet etc I seem to once again stabilized with no further weight loss.
    I suspect it is because I cannot totally give up my craving for sugar as I do have the odd dessert and sweeteners in my coffee. What do you reckon? Do you think like you it is no sugar whatever? I have tried hard but the best I get to is having honey in my coffee but the sugar demons keep driving me crazy.

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