The #1 cause of obesity: insulin

Oh my god. This 3rd episode of “The Skinny on Obesity” may be the best short video on obesity I’ve seen. Not because Dr Robert Lustig tells me something I didn’t already know, but because he explains it so crystal clear that a kid will understand.

Do you want people to understand the reason behind perhaps 90 percent of obesity epidemic? Spread this video. It needs to be seen by as many people as possible.


The bottom line is that the cause of garden-variety obesity is relatively simple: Excess (processed) carbs increases insulin which increases fat storage. Some bloggers on the internet have objections to this, but that does not change the facts.


  1. Ian
    It explains why I am much less hungry since I stopped eating processed foods and sugars. Ketosis has allowed leptin to work again. Thanks for posting this!
  2. Alexandra M
    That was excellent! I wish the previous one had been better, and hadn't damaged (IMO) his credibility. Because for some people a "crystal clear" explanation usually gets labeled "a just so story."

    As in this comment on Steve Novella's blog (where he says, "After many studies looking at this issue from many angles the results boil down to a few simple rules. For weight control exercise on a regular basis and find some way to control overall caloric intake long term. There are no magic diets, special foods, or optimal proportions of macronutrients that will make calorie restriction easy. Reducing total fat seems to be helpful.")*

    "I thought, at the time, that the low carb thing is what did it for me. I even used biochemical justifications (aka just-so stories) to explain it."

    "... tells me something I didn’t already know..."

    Which part?


    (I know I posted this link the other day .)

  3. I thought this was much better than the second episode (which is confusing because of his insistence on calling sugar a fat until you've seen why he says that in THIS episode), but it feels like he didn't quite get the "punchline out"--excess carbohydrate intake causes excess insulin.

    He does refer ever so briefly to the "modern industrial diet" but I think the point needs to be as clearly illustrated as the "excess insulin causes the body to turn sugar into fat" point. Hopefully he will do so in subsequent episodes.

  4. Justin B
    Alexandra, that kind of stuff frustrates me. They just pretend that the clinical studies haven't been done-- that the brain scans haven't been done-- that the biological effects haven't been tested.
  5. moreporkplease
    Alexandra & Justin:

    Every contemporary biochemistry textbook will tell you that insulin causes fat storage. Every single one. You can search on Google Books for your self to verify this. Every doctor who has passed biochemistry has learned this, been tested on this, and passed. Every doctor with clinical experience with T1D people will tell you this. Lustig's explanation of the mechanism is basically what you will find in the biochemistry textbooks.

    This is not unknown, unsettled or in doubt. If you call a commonly-taught scientific fact with experimental proof, a known and validated biochemical mechanism, and many many clinical results a "just so story," then I have to question your credentials as a doctor. Novella bills himself as a "skeptic," but there's a point at which "skepticism" becomes tin-foil hattery.

    Nowhere does he offer an alternative mechanism, biochemistry, or robust clinical/experimental evidence to deny the action of insulin in this case. Out-of-hand dismissal is not a scientific argument. If the book-standard biochemistry is wrong, offer robust experimental evidence.

  6. Alexandra M
    "Alexandra, that kind of stuff frustrates me."

    It pretty much makes me spit glass. Novella and his followers are all about science, RCTs, peer review, evidence, etc. - until it comes to the epidemic of obesity and diabetes, and then everything is chalked up to some sort of mass delusion and magical thinking.

    (Sorry if I derailed.)

  7. 1 comment removed
  8. Maggan A
    Alexandra M

    "eating too much and not exercising enough because of your weak character"

    That is truely one of the biggest lies. My oldest son is moore than 100 kg and he is a construktion worker. He keepes his body mooving 8 hours/day, But unfortunatatley he is addicted to carbs... as for character no mother could be more proud than me,,,

  9. Margaretrc
    I think Alexandra M was criticizing Steve Novella, not agreeing with him LOL.

    This is great. Why don't Stephan Guyenet and his followers get this? And Steve Novella? Did they not take Biochemistry?

  10. Alexandra M
    "Why don't Stephan Guyenet and his followers get this? And Steve Novella? Did they not take Biochemistry?"

    Sometimes I think it is because of some remnant of Puritan religious belief:

    1) The idea that somebody could achieve weight loss and better health without suffering and sacrificing just rubs them the wrong way. "It's not fair! It shouldn't work that way!"

    2) Real foods like fatty meats and cream and butter are associated with luxury and indulgence - sinful pleasures, in other words. It "stands to reason" that eating these foods will make you fatter and sicker (the wages of sin). After all, they can't eat them! They've been giving them up for years and they're still fat. What makes you think you're so special that you can eat them and lose weight?

    Short answer: biochemistry.

  11. He had me until he equated normal 'hunger' signals with "STARVATION!!!" OMG!!! EAT SOMETHING, QUICK, STAT!! IT'S BEEN 2 HOURS, I'M STARVING!!! I'M GONNA DIE IF I DON'T GET SOME MORE FOOD IN ME ***NOW!!!***

    Please, reinforcing the 'Need To Feed' hysteria only perpetuates the myths, misinformation and outright lies that cause people to become obese.

    Go read the Wikipedia page on the human starvation response, it takes a looooog time & an extreme situation to truly enter the starvation process.

  12. Wolfstriked
    Thanks Dr.Eenfeldt,excellent stuff.Explains how in the world I was ordering $20 dollars worth of Chinese foods and eating it all within an hours time when I weighed 300 pounds.My hunger was so bad that I would eat two normal breakfasts(2 eggs,toast,home fries) and drive a truck for 2 hours and be starving again.Steak and cheese sandwich for brunch(footlongs).etc.

    That said I think that the final straw for obesity "could" be fitness level.I posted this on Paul Jamiet's website "Perfect Health Diet" a week ago.Since then I have slowly gotten to 12 flights of stairs straight up done today.Today,for the first time in what feels like a decade,I am looking at buying size 30 waist clothes.And all this time I have been doing low calorie/low carb/high everything etc.All the diets yet these last 25 to 30 pounds just hung around.That is until I added in what I feel might be the missing link.And this running up stairs is not that bad as long as I follow one till I feel bad and stop.I started with 3 flights and was wasted and slowly it went up one flight per day.Today I got to 8 fl with ease as if I was walking around.Its funny that I always tell people I have a strenuous job yet I collapsed on 3 flights.Walking around,no matter what they tell you,is not enough to increase fitness.

    So my theory is that maybe some people just get out of shape cardiovascular wise faster than others.Could explain the reason some people just eat whatever they want and never gain weight.But a lot of these same people,when you meet them yrs later,have a nice bulging waistline.Maybe not obese but started down the road.And who knows,maybe sitting around more and more will eventually lead to obesity for them too.

    That said,I am also all for the insulin hypothesis.I get very unhealthy looking when I eat a normal diet,even if lower calorie.Not only unhealthy looking but it's as if insulin,or unstable blood sugar,ages me quickly.Right now I am back to Atkins/LCHF eating and stair running and results are amazing.

  13. Maggan A
    Alexandra M

    Yes the "pleashure of the flesh" is still a problem for people hwo can not accept the fact that we "humans" are animals and predators like lions and wolfes... ore eagels....

    I dont know about the rest of you but I feel proud of beeing a member of that gang ;-)

  14. Monicas Mat
    Jättebra film! Tänker på alla hyllor med "mat" i butiken när man handlar, man får leta efter den naturliga riktiga maten utan tillsatser, socker, stärkelse....
  15. Dina
    The best episode so far!

    True that using 'starvation' instead of 'hunger' is a bit harsh, but I've come to the conclusion that apparently the American audience needs superlatives ... ;-)

  16. FrankG
    I don't think that Dr Lustig is describing normal "hunger". I think that "starvation" is a more appropriate term for the condition he is discussing:

    * the need to eat is a primal drive from our lower or reptilian brain -- much like the need to breath or drink water... we may consciously subdue these drives temporarily but we cannot ignore them for long without consequences.

    * with chronic high levels of insulin and insulin resistance, the drive to "feed the beast" and preferably with fast acting, high energy foods, is extreme and, in my experience, pretty much constant

    * since switching to a real whole food diet that is naturally LCHF I am no longer "hungry all the time" -- indeed I can easily skip meals if I have the need -- what I experience nowadays feels more like natural "hunger" to me, rather than the constant craving "starvation" I lived with for over 25 years

    * we may equate the word "starvation" with scenes of famine in developing countries, but I am sorry to say there are many others who, while apparently surrounded by plenty, are still malnourished.

  17. TheFatNurse
    It will be interesting to see how far Lustig is willing to go with this...will he tell people to eat less carbs and more....fat? When RM Krauss discovered that LDL was not as bad as previously thought with his research on LDL particle sizes many of the doctors and nutritionists during that time found his research remarkable...but wouldn't comment on its implications on what it meant about diet (it would potentially oppose the low fat dogma).
  18. Irene
    Can i recommend to anyone who has high blood sugar or is diabetic to take Cinnamon Ceylon Powder, you can buy them in capsules too, Cinnamon Ceylon will help reduce blood sugar levels and it is available on amazon and just make sure u get the Ceylon one's as the other cinnamon is actually bad for u, hope this little tip helps.
  19. Nat
    This guy needs to take a time out to study social behavior and public speaking. He is patronizing and comes across as a douche. Fat, Sick and Nealy Dead is much better at explaining obesity.
  20. Alexandra M
    Losing weight on a juice fast is not "explaining obesity."

    I agree Lustig's manner could use a little work, but I'm not going to quibble about the color of the lifeboats when the ship is sinking.

  21. Galina L.
    Now I know there are different kinds of hunger. The one which used to drive me crazy and controlled my behavior before I limited carbs and the one which is more like a mild desire to eat, and I have a choice to follow it or not. I am free from that maddening urge "I HAVE TO EAT NOW!!!" first time in my life. It is truly priceless and is worth by itself all that limitations I have to impose on my diet. I lost weight and gained health, of course, but I lost weight before without such changes.
  22. Jen
    "Why doesn't Stephan Guyenet get this? Did he not take Biochemistry?"

    To "prove" Taubes wrong, Guyenet is completely willing to throw science under a bus.

  23. moreporkplease
    "Why doesn't Stephan Guyenet get this? Did he not take Biochemistry?"

    The more pertinent question is who funds Guyenet and why. Could it be that if you're being paid to work on a brain-based drug to treat obesity, it's in your interest to destroy the insulin hypothesis? Notice how no one ever speaks of Guyenet's funding.

    Taubes, we know he's paid by his publisher to sell books. But Guyenet? Who knows where his money comes from?

  24. Justin B
    Nat & Alexandra,
    It seems like the longer a researcher has been trying to get the message out there, the more disgruntled they seem, that it hasn't caught on. Lustig, Taubes, Cordain, etc., all have that "Why is nobody taking this seriously!?!? Its so obvious!!!" tone.
  25. Zepp
    I do think that it is a bad thing to demonise Guyenet, he have some strong points and som bad points to!

    And there seems to be a personal antagonism betwen him and Taubes.. that not helps the cause!

    And I do belew that he have taken a lot of biochemistry classes to know there is no simple explanation.

    One thing is what hapens when you got a damage metabolism.. preferbly metabolic syndrome, and whats realy causes it!

    There are probably different patways to go there, one way is probably a high glycemic load, but thats not the whole explanation.. there is probably more things to cause a metabolic breakdown.

    And I do hope no one gonna say that Insulin is a bad hormon.. when it juste doing its job, its hyperinsulinemia thats a bad thing.. almost in every case caused by hyperglycemia, how is caused by lower glucose tollerance.

    So, insulin juste try to save your body from toxic overload of glucose to minimise damage of internal organs.

    And when somebody do have reached this point, its better to avoid to much carbs.. thats what we know.. the rest is hypotetis.. to be proven!

  26. BA
    The reason that Taubes finds Guyenet's advocacy of the Food Reward/Palatibility Hypothesis unsatisfactory is that he views it as just a more sophisticated way of putting obesity back into the realm of psychology, instead of what he views as the real story, which is that of hormonal regulation in the body. I personally tend to agree with Taubes, but Guyenet's work might actually give us some decent insights into the mechanisms behind why carbohydrate-rich foods are so habit forming.
  27. Alexandra M
    I confess I haven't thoroughly examined Guyenet's hypothesis. But I agree it ends up back in the "psychology" explanation. And that is (IMO) a crap explanation of what is happenng. When a huge number of people are completely miserable about their weight and would try just about anything (see people signing on to any number of weight loss scams) and still can't lose weight, that suggests a problem in the food environment, not in the people,
  28. Ken
    Maybe it's just me, but doesn't the supposed role of leptin as explained (at the very beginning and end of the clip) by Lustig seem completely superfluous? He describes a model in which excessive (exogenous or endogenous) insulin diverts some of the energy (from meals) into storage and hence induces overeating to satisfy a purported overall requirement (of the energy-burning tissues) -- where the body "feels good". This does not involve leptin at all, and seems to entirely explain the overeating (according to his proposed model).
    But then he adds that hyperinsulinemia causes leptin resistance and hence excess hunger, having said at the start that the discovery of leptin was critical to a complete model of obesity.
    His claims don't jibe together -- sounds like PC BS to me. His theory is based upon insulin alone, and he is gratuitously throwing in leptin because it's a faddish research sinkhole for his cohorts.
  29. Galina L
    Just because there is some mentioning of a leptine, I want to place a link to several blog post of the blogger who managed to loose 180 lb out of 300 lb by following a LC diet AND receiving injections of leptine (she participated in the leptine study). She is still size 0 after 10 years since her weight loss.
  30. Linda
    I am 66 and diagnosed T2 diabetic about 10 years ago.
    I would love researchers to look into this. NEVER in my life have I felt full. After eating,say, Christmas dinner - I could eat it all again.
    I took up running 6 months ago. I was invited to go for a curry with some friends. On my way down to the curry house I felt so full I simply could not face eating a curry.
    I put that down to the run I did that morning. This is a great turnaround and one I am actively pursuing.
    Will the regular running be the reason?
    I am considering LCHF diet but I am afraid of the fats in cheese, cream etc.
    Could anybody who has succeeded in losing wight with LCHF please advise me?
    Reply: #31
  31. Zepp
    Read this!

    Im no diabetic.. but I got a HbA1c of 32.. on a LCHF diet!

    And you can use this approche for your diet!

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