Obesity and the trouble with sugar

Here is professor Robert Lustig’s insightful talk from AHS – again. This time the slides are included in the video (not always perfectly synced) which makes the video much more watchable.

Lustig has a very believable explanation to how our weight regulation works, and why it sometimes do not. The core of his message: Too much fructose (or even more glucose) in the diet increases the hormone insulin which induces leptin resistance and makes us want to eat too much.

See his talk and you will understand more about obesity than many confused experts do. Personally I have seen it three times, which makes me feel very smart.

All about weight loss


  1. You may find that listening to a different version of similar Lustig presentations gets the points home.

    Interventions to Reduce Sugar Consumption

    Authors@Google: Robert Lustig

    I suppose I'm a bit of a slow learner as hearing the same information in different presentations seems to work for me.
    I've listened to all the Taubes Adiposity 101 online versions for the same reason.
    I'm assuming everyone has listened to Sugar: The Bitter Truth - YouTube

  2. I offered a critique of Lustig's view on fructose: http://wp.me/p16vK0-6W What he and I agree on is that simply cutting out sugar, or even sugared soft-drink can be a quick way to reduce weight and improve metabolism.

    It may also be that if you are on a very high carbohydrate diet replacing some of the fructose with glucose (replacing sugar with starch) may be beneficial but this effect is very small compared to replacing any carbohydrate with fat. This has been demonstrated many times especially by Ron Krauss who is a co-author on the AHA paper that Lustig cites.

    His presentation of the science is also full of gross mistakes. Fructose is a sugar and is metabolized like a sugar, different from glucose but the metabolism has little in common with the metabolism of ethanol. The metabolism of fructose and glucose come together at a certain point and so are inter-convertible. That is why the glycemic index of of fructose is 20 and not zero. (Glycemic index is a measure of the effect of carbohydrate on blood glucose; glucose - 100) What's really wrong with the biochemistry is that Lustig acts as if this is all known and simple. It's not. The concern is that setting up fructose as a villain will be another smoke screen like trans-fat, saturated-fat, fiber, for not facing the need for carbohydrate restriction.

    Bottom line: your best bet for obesity and metabolic problems, is carbohydrate restriction. Which carbohydrate is strictly secondary. Lustig's talk was part true, part snow-job, part gross mistakes. Much better from AHS was Andreas's talk which nailed the problem beautifully.

  3. Dr. Andreas Eenfeldt, MD Team Diet Doctor

    Interestingly Lustig said in the Q&A (starting at 44 min) that he had no problem with anything I said in my talk, he basically agreed, he just wondered if it was necessary to be that "extreme". :)

    Lustig acknowledges in this talk that fructose can end up refilling the liver glycogen (turning into glucose first) but only if it needs a refill, not when it's already full. So Gatorade might be ok for athletes (except for their teeth), but not for the rest of us.

    Regarding the fructose-ethanol comparison from his Sugar: The Bitter Truth talk, that sounds a bit dodgy for me too. I don't have the biochemistry expertise myself to say for sure, but I guess you are right.

  4. As a Registered Social Worker, former bulimic and owner of a weight-loss counselling service, I agree with sugar (in whatever processed form) contributing to obesity. Sugar and sugar substitutes are extremely addicting especially to children. Sugar causes hormonal imbalance disrupting every aspect of our function. My focus is on the emotional and mental aspect of overeating and food addition. Sugar is the quick-fix solution to cope with the remainder of our day, therefore causing an emotional dependence on it. In my book, Eating Ourselves Crazy, I emphasize the importance of weaning from sugar in order to stabilize hormones and moods.
  5. moreporkplease
    For so many people low-carb seems impossible, daunting. Most people will do best "cold turkey," and yet not everyone can follow that approach.

    I love Lustig's "baby step" approach for these people. It's easy to first switch to diet soda with splenda. Then it's easy to switch to cooking with splenda.

    Then it's easy start reducing the splenda or cutting back on servings of diet soda. Most folks will have lost some weight after about a month of this, and be motivated to continue on. There's no social sanction about giving up sugar; in fact, most people will congratulate you for it, even.

    Then it's easy to avoid bread - by choosing either bread OR pasta - not both. After avoiding bread, avoid the pasta. Weight loss will increase, providing more motivation. And again, becoming gluten-free is something that is now receiving more social approval.

    And so on. In a month or 2 people will be easily low-carb without feeling "deprived" or running into the social backlash against low-carb, or "Atkins," which in many circles will get you serious social punishment. :) To avoid the Atkins backlash is why I think Lustig calls low-carb "extreme." :)

    As for his science, he's a professor. I'm sure if you simply point out the errors in biochemistry to him, he will gladly correct them. This is normal scientific behavior, to accept feedback, correct, and improve. :) I've read people who meet him saying that altho' he seems combative in speeches, he's actually rather nice as an acquaintance. :)

  6. You have a description of a strategy for easing into low carb. Is that what you did? Is that a strategy that other people have tried? Or is it a guess? Not giving you a hard time but Lustig calls Atkins "extreme" because that's what he thinks it is. He doesn't talk to people who find it easy to do. As for social backlash, you don't have to tell anybody you are on the Atkins diet but it is a good way to find out who is open-minded, who are supportive people, etc.

    Lustig is a nice guy. We had a long talk at AHS and we continue to communicate. I explained what we agreed on. On our disagreements, we are trying to discuss things and neither of us want it to be personal. His position is, in my opinion, way off the mark. One way to describe the differences is that in science if you don't know, you don't know. In medicine, if you don't know and the patient is sick, you have to do something. That's why people think highly of doctors because they are willing to shoulder that responsibility. So without blaming him, there is a real threat of fructophobia.

  7. Clint Primoff

    Can you clarify regarding fructose being inter-convertible with glucose. Is fructose inter-convertible with glucose in the context of a caloric deficit, but not inter-convertible when consumed along with an excess intake of calories (or, I should say, when glycogen is replete)?

    Is it possible that metabolic derangement from fructose occur only when excess calories are eaten or glycogen stores are full?

  8. Alexandra
    @Treena I spent my life listening to people blah blah blah about the emotional and mental reasons fat people (like me) overeat. Honestly, it's just the carbs.... once I dropped my carbs to 20 net per day, it took about three days for my body to adjust (It can certainly take longer) after that, all cravings, all preoccupation with food vanished. Did I suddenly go from weak to strong? No. Did I suddenly become mentally or emotionally healthier? No. Did I suddenly develop new willpower? No. I am the same person in every way except I no longer am compelled by my high carb diet to eat, eat, eat. I am 120+ lbs lighter and have about 20 lbs to go. I eat until I am full at each meal (LCHF Paleo) and then forget about food for most of the day.. Bliss!
  9. Chris Searight
    Maybe I'll have to watch the Bitter Truth lecture again, but I didn't think Lustig was saying that fructose and ethanol were metabolized in the same way. Rather, the process is different but the end results are similar. What I took from it was: Ethanol is considered a poison, fructose has similar effects, shouldn't fructose be considered a poison as well?

    The question I have about Lustig's AHS lecture is the idea of seasonal insulin resistance. The idea makes sense to me from a high northern latitude perspective. However, I have no idea about the climate of Africa, nor the available fruit, over the past 2.5 million years. I've read accounts of African peoples having no problem catching different animals at different times of the year. It would be interesting to look up sources, if I had the time.

  10. I will try to answer Clint's question in detail in the future. Bottom line: both glucose and fructose are 6-carbon sugars (hexoses). The "lysis" part of glycolysis means that they both get broken down to 3-carbon sugars (trioses). So the pathways of F and G metabolism converge at the level of the trioses which, in turn can be used to re-synthesize glucose (or put glucose into glycogen), or can be used for energy, or for fat synthesis. Which happens when? Well, it depends on all of the conditions in the cell (and hence the body). It is all connected and it all goes on at once.

    You are correct that at high caloric or specifically high carbohydrate intake, F will contribute more to fat synthesis but, even here, again, the effect is much less than replacing any carbohydrate with fat. The effect of glycogen is probably not known. The idea that it is not interconverted with F if glycogen is high is probably made up by Lustig. Glycogen is broken down and resynthesized all the time.

    What's wrong with Lustig's biochemical map is that, like any map, it only tells you where you can go, not whether you are going there. If this is not concrete enough, I think it is the state of the art. We don't know the relative responses under every condition. We are not ready to say that fructose is inherently worse than glucose under most conditions. And we are especially not ready to start making policy. The government can do a lot of things. Provide education have hearings, etc. The first response of politicians is to tax or otherwise punish. That's what Lustig wants. Don't see much promise there.

  11. To answer Chris's question. Alcohol is not a poison. It is a normal food and is processed by introducing it into the Kreb's cycle (energy producing pathway). At high concentrations, it ceases to be a food and is a drug or, if you like, poison and is not longer processed for energy but is metabolized like a foreign substance. Everything can become toxic at high concentrations but the metabolic overlap in F and alcohol is a stretch at best.

    Now both have behavioral effects and may stimulate convergent neuronal pathways but this is not really my area of expertise. Both can be consumed to excess but not always by the same people. Psychologists distinguish between reinforcing value (continued behavior) and hedonic value (tastes good). I am fond of single malt whiskey but rarely drink two days in a row. On the other hand, I avoid ice cream because I find it personally habit-forming. My guess is that Lustig and I could drink to that.

  12. @Alexandra
    Yes, generally sugar and high carbs go together. Both are used as a quick solution to replenish our good mood chemical, serotonin. I explain how there are legitimate reasons for cravings for sugar and carbs. Stress, in any form, mental, emotional or physical usually results in cravings due to the disruption of hormones, depletion of good mood chemicals and low blood sugar. As a former compulsive eater, I have a personal understanding of how difficult it is to overcome emotional-eating due to our addicting modern foods. There is so much more at play than just craving a bowl of ice cream after a emotionally-taxing day; there is just as much physiologically as there is psychologically.
  13. FrankG
    Here is a short version of Lustig's "Sugar: The Butter Truth" as presented by Sean Croxton at Underground Wellness...


    I'm not sure I see Lustig setting out to demonize Fructose itself but rather the *excessive amounts* of it that are eaten/drunk these days. In his follow-up podcast interviews with Jimmy Moore at "The Livin’ La Vida Low-Carb Show" he is quite clear in calling it a "dose-dependant hepato-toxin"... just like alcohol: a small amount may be beneficial or at the very least harmless, but above a certain level it causes harm. Presumably the frequency of intake is also a factor, although if amounts are small, less so.


    With that all said though, I still see a very clear common thread from many voices advising that we reduce/avoid sugar and refined starches as found in processed/packaged "foods"... and that we have no need to fear naturally occurring fats as found in real whole food.

  14. This report
    Breaking down the Chain: A Guide to the soft drink industry gives us an idea of the size and power of this industry.
    Apples to Twinkies: Comparing Federal Subsidies
    of Fresh Produce and Junk Food"
    summarises the food subsidy element.

    I think maybe the current arguments in the Paleo/low carb community we are getting our knickers in a twist about the biochemical details when what is really at fault is our over-reliance on ultra processed foods.
    This paper makes some interesting points.
    Technology, Diet, and the Burden of Chronic Disease
    and makes some sensible suggestions.
    Example of Measures to Promote a More Appropriate Use of Food Technology
    Restructure agricultural subsidies to promote highquality foods (eg, vegetables, fruits, and legumes)
    Regulate food advertising/marketing, especially to children
    Adequately fund school lunch and related nutrition programs
    Buy fewer ultraprocessed products
    Prepare meals from basic ingredients in the home
    Give preference to restaurants that prepare meals from scratch
    Prepare lunch and snack foods from whole ingredients
    Institute a new “home economics” curriculum to promote cooking
    Provide intermediate option between gourmet food and fast food—convenient, inexpensive meals prepared from whole foods (eg, Chipotle Mexican Grill)
    Use higher nutritional value ingredients vs commodities
    Market minimally processed/traditionally processed products (eg, stone ground bread, steel-cut oats)
    Use preservation methods that protect polyunsaturated fats

  15. Amy
    @Alexandria @ Treena
    Ditto, you said it beautifully. I used to NEED chocolate everyday with cravings I liken to when I smoked and NEEDED a cigarette. Therapists convinced me of a food addiction along with emotional eating. The cravings ruled my life even after I had dealt with the emotional issues. My depression was gone; I felt happy but for those cravings and my so called lack of willpower. In March 2011 I watched FatHead and my whole view changed. I stopped the sugar I stopped the carbs and began LCHF. Today I have zero cravings and I only think of food when I am hungry. I find I am so sensitive to sugar that even fruit will bring the cravings back.
    Another side to this is the fact that I had always been very thin naturally. I was a model. When I was pregnant I gained 100 lbs because my cravings were so intense that I never felt satiated. These cravings were a new phenomenon with me. This cycle of cravings, self blame and weight gain has continued until now when my child is 16 yrs old. I finally feel back in balance and the weight is coming off. When Dr. Lustig mentioned the times when it is normal to gain weight, puberty and pregnancy, I got the answer I had been searching for. My issue was a continuing imbalance between my leptin and insulin not my willpower. I am the same strong woman I was in March 2011.
    Oh yes, and also during my pregnancy I became lactose intollerant, now I can gleefully take heavy whipping cream in my coffee with no problem. My child was also lactose intollerant until I stopped nursing.
  16. Jess
    I followed the hcg diet for 4 weeks, lost 18 pounds, this mainly helped me get rid of my addiction to sugar. even though I sometimes still feel like grabbing something sugary, I haven't yet. I feel great, less jittery, more focused, less moody etc etc.
  17. I think it is more of a problem of compression to 45 minutes than an error in knowledge.
    Basically, the problem is excessive carbohydrates, all carbohydrates. some people can a few, but which do need need top cut first, and see where our settling point is at. Too high, cut more.
    Lustig says cut fructose,
    Many say all sugars.
    Davis said wheat first.
    Kessler says all.

    The simple solution is to cut all carbohydrates, transfats, omega 6 oils, until we reach an acceptable settling point.

  18. Amy
    I did the HCG diet of 500 calories a day and the drops. I felt horrible had no energy and was starving all the time and constantly thought of food. A complete nighmare that lasted 10 days. You can say I needed to up my dosage or that the shots are better; I dont think that matters, HCG is a bunch of baloney.
  19. Alexandra
    @Amy I can't help but wonder how many people, women in particular, are in therapy or counseling hoping to overcome their compulsive eating when what they really need is to cut out most the carbohydrates and go spend that therapy money on high quality real food.
    Would a therapist ever say: "there is nothing wrong with you, you just need to stop eating most carbs." BTW My lactose intolerance also went away when I started eating LCHF.
    @Fredt I agree... and once it's gone, you really don't miss it...
    Also, for those trying to decide, I think eating to satiety at each meal is such an important component. This is not about starvation. You will see, you won't even want a snack! and, as I said before, forgeting about food for most of the day is bliss.
  20. eddie watts
    with all this talk about satiety i would recommend reading through the series on http://www.gnolls.org on that subject.
    truly eye opening
  21. @ eddie watts I agree, I think the idea that applying pressure to folks to lose weight, and condemning those who fail sets the scene for raising stress levels and the results are inevitably counter-productive.
    "The Impact of Weight Stigma on Caloric Consumption"
    The more people say "It's simply Calories in = calories out, so exercise more and eat less = problem solved the worse the situation gets.
    We gave got to understand what drives the need to eat and what prevents/discourages activity and if we want to prevent weight regain we have to understand how to reset the natural control system and restore mitochondrial function.
  22. Greg
    I don't like that CIH (carbohydrate-insulin hypothesis) and food reward (what is reward but hormonal regulation?) are being opposed to each other as they are. I think they have a lot in common, and mostly where things differ is whether insulin or leptin is the most interesting hormone in the chain. But I think the food reward folks shouldn't lose sight of the fact that the dramatic insulin response to a carb spike tends to subsequently cause hypoglycemia, which in turn causes hunger - so here we have a concept compatible with food reward hypotheses that also fits with well-established (and documented) positive effects of low-carbohydrate dieting. More specifically, this circumstance is NOT about insulin's effect on adipocytes, which is why it doesn't fit in the CIH.
  23. Alexandra
    I will happily follow the progress as the details of what makes us fat and what keeps us slender are figured out. The beauty of it all is that even if we don't know everything, what we do know really works! I have never felt better in my entire life. I have more energy now than when I was a fat little girl in the 1960's. I hope people won't wait because not all of the science is fully understood. Get started!
  24. If you've been following the comments on Hyperlipid http://www.blogger.com/comment.g?blogID=36840063&postID=62326671...
    and seen the points about high insulin increasing iron overload you'll realise why the quality and amount of sleep (melatonin - iron chelator- mitochondrial protecting) is part of the obesity story. I'm also concerned that people will be bored/put off by the infighting and think it's not worth the effort. Those here who have followed the Taubes/Dalhqvist/Diet Doctor strategy and found it was sufficient to help, don't really have to worry if it was the insulin/leptin or simply the fact that the absence of food cravings led to a reduction of calorie intake that enabled the weight loss to occur. I'm sure the anti inflammatory (vitd/mag/omega3/melatonin status of the Kitavans/Masai privitive cultures would have impacted on their ability to eat high unrefined carbs with impunity.
    We just have to consider how sunlight affects the progress of NASH in rats
    to be able to make a reasonable guess about how outdoor living in sunny countries may impact on insulin/leptin resistance. But how that applies to Western Cultures glued to PC/TV indoor living is a different matter.

    Just because the sundrenched Kitavans survived on a high carb diet may not apply to those living in the UK for whom the current sunny weather is a welcome change I hope all other UK readers are taking full advantage of.

  25. There you go again, Alexandra, talking common sense and reasonableness.
  26. eddie watts
    @ Ted: i certainly am, my breaks are spent in works car park right now soaking up those rays. soon i'll have to go and buy vit D tabs for the winter, but right now i'm enjoying the natural source. although i do find when i get i after all that sun i fall asleep, even though it is only 3:30 in the afternoon!

    my concern is that the fall outs over certain aspects will lead to a "divide and conquer" situation wherein lowcarb/paleo loses out due to the infighting.

    also Andreas: i finally got my wife to watch your speech last night, been trying since it first appeared on youtube. she was enthralled and it really helped towards getting her to cut down her chocolate and other occasional treats (read occasional as daily) as she quit smoking earlier and did confess that she feels like her food treats, which are always sweet and sugary, are the only vice she has left.
    anyway looking forward to a healthier and leaner future for her :D

  27. tam
    After the Sugar the bitter truth video, I gave up all sugar. But I replaced it with sprouted whole wheat bread. End result: I gained weight. Now I've given up wheat for a month, and I'm losing weight.

    Dr. Lustig should do a multivariant analysis on himself, and see what happens if either the amount of glucose or fructose are changed.

  28. Greg
    @tam, I had a similar experience. I essentially eliminated fructose from my diet - brown rice syrup, sprouted english muffins... it was hard to do, I have to say. And ultimately it had lackluster results. Cutting back on total carbs, irrespective of type, caused me to lose a ton of weight. The problem is that I have been fighting a tendency to become obese since childhood, and as such my metabolism isn't a "clean slate" for measuring the effect of things. No matter what direction the wind blows on theoretical causes of obesity, LCHF is quite simply the most effective known treatment available.
  29. GoEd
    In my opinion, the first actions for anyone that wants to improve health should be to cut out wheat and soda.

    Soda obviously contains a lot of fructose.
    However, regarding wheat there are heaps of other problems then just the starch it contains. Check out Dr Davis new book Wheatbelly


    If you do these two actions, you probably achieved 80% of the benefits of a low carb diet.

  30. Dr. Andreas Eenfeldt, MD Team Diet Doctor
    I think you are right.
  31. Alexandra
    @Doc and GoEd... the only thing I would add to that is, for me, going part of the way is actually more difficult. Too much of any carb and I return to having the cravings and food preoccupation that kept me fat since I was in grade school. I would say to anyone getting started to really pay attention to how much you think about food and the inevitable clock watching for the next meal or snack and adjust accordingly... When I keep my total carbs very low (20 net for me...your number will vary) and eat enough fat, I completely forget about food for hours and hours and snacks, they are a thing of the past. This is the key to the whole shebang, in my humble opinion.
  32. See Sugar the Bitter Truth children's version http://www.youtube.com/watch?v=_PMQvamaAcc
  33. Sugar, unfortunately, is just the beginning of the food trouble in the world, USA in particular. I usually read up on these things before committing to any type of diet. There's a great site called http://GetYourDiet.com that talks about the hottest new trends out there. My favorite is http://getyourdiet.com/review/xtreme-fat-loss-diet/
  34. Ali

    I found going instantly low carb no problem at all. I get really tired of people's claiming it is difficult. I also get tired of claims that it is harmful, by people who when quizzed can't tell you a single food in it.

    I am with Alexandra. In the face of this extreme emergency... Obesity epidemic... Diabetes explosion.... Cancers... Heart attack.... surely the most logical thing is to stop doing what doesn't work i.e. food pyramid/healthy plate, and start doing the thing that seems to work for everyone, even if we don't know why. No drug ever given to me as a critically ill, undiagnosed celiac caused any improvement in my health. In contrast, LCHF Paleo gave me the ability to walk again, and see properly, within days. I lost fifty pounds without even trying. I cured my ataxia. The answer does not lie in a medicine bottle. Nor, sadly, with most doctors at the moment. There is massive and overwhelming ignorance.

  35. Janknitz
    Dr. Lustig spoke in our community this week as part of the 19th Annual Latino Health Forum. http://latinohealthforum.org/pdf/2011-brochure.pdf

    I wasn't able to attend, but it sounds like he gave his usual lecture, emphasizing the impact particularly on Latino kids whom he described as having "a genetic predisposition to developing health issues from overconsumption of fructose. . . Sugar-sweetened drinks are prevalent in the Latino culture, he said." (http://www.pressdemocrat.com/article/20111014/OPINION/111019699?p=2&tc=pg)

    Now here's the really scary part! Leann Weintraub of Sherman Oaks, California, felt compelled to respond to Lustig's lecture by writing a letter to the editor in our local paper. She described herself as "a registered dietician counseling children and adults with obesity", and the thrust of her letter is that "sugar is not to blame for America's health and weight problems". She attributes the obesity epidemic to "lack of physical inactivity [sic--was this a typo, or a Freudian slip??], and (here's the fun one) "lack of science-based nutrition information." She counsels her (poor!) clients to adopt a more "balanced approach" (because everyone needs sugar in their balanced diet!) including "nutrition literacy, sensible portion sizes, and physical activity."

    Amusing in and of itself, but it was the last paragraph of her letter to the editor tells all:

    "When I consult for food and beverage companies such as Coca-Cola . . . "

    'Nuff said!

    Ms. Sherman's letter to the editor of the Santa Rosa Press Democrat may be seen in its entirety here:

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