Review: The Obesity Code

      78 Comments on Review: The Obesity Code

I recently wrote a couple of posts explaining that over the years, I’ve revised my explanation of “the alternative hypothesis” from this:

More Carbohydrates => Higher Insulin => Fat Storage

to this:

Damaging Diet => Hormonal Disruption => Fat Storage

It’s not the biologically beneficial rise in insulin after a meal that makes people obese, I said in those posts. It’s chronically high insulin (along with other hormonal disruptions) resulting from a bad diet.

In comments, a few of you suggested I read Dr. Jason Fung’s book The Obesity Code because it expresses similar ideas. Good suggestion. It’s an enlightening and very readable book – meaning it passes my “Aunt Martha” test. Your Aunt Martha could read this book without giving up because she doesn’t want to keep a medical dictionary on her desk.

As I expected, insulin is still front and center in Fung’s explanation of why we get fat. In fact, the book’s cover includes the subhead Why your body’s own insulin is the key to controlling your weight. After citing plenty of research to effectively dismiss the “it’s all about consuming too many calories” explanation of obesity in the early chapters, Fung begins chapter seven like this:

I can make you fat. Actually I can make anyone fat. How? By prescribing insulin. It won’t matter that you have willpower, or that you exercise. It won’t matter what you choose to eat. It’s simply a matter of enough insulin and enough time.

Wait … hasn’t Dr. Fung read on the internet that we mustn’t blame insulin because it’s actually a wunnerful, wunnerful appetite suppressant? Well, perhaps he has … but if so, I’m sure he laughed. He has years of clinical experience with the stuff, as he explains in the book’s introduction:

I’ve often watched patients start insulin treatment for their diabetes, knowing that most will gain weight. “Doctor,” they say, “you’ve always told me to lose weight. But the insulin you gave me makes me gain so much weight. How is this helpful?”

… Like many doctors, I believed that weight gain was caloric imbalance – eating too much and moving too little. But if that were so, why did the medication I prescribed – insulin – cause such relentless weight gain?

Fung answers his own question in chapter seven:

Everything about human metabolism, including the body set weight, is hormonally regulated. A critical physiological variable such as body fatness is not left up the vagaries of daily caloric intake and exercise. Instead, hormones precisely and tightly regulate body fat. We don’t consciously control our body weight any more than we control our heart rates, our basal metabolic rates, our body temperatures or our breathing.

But it isn’t just about insulin. Fung includes chapters on cortisol (which triggers weight gain partly by raising insulin) and other hormones, such as leptin, that are involved in weight regulation.

And insulin isn’t just about how many grams of carbohydrate we consume. As Fung writes in chapter nine:

The carbohydrate-insulin hypothesis, the idea that carbohydrates cause weight gain because of insulin secretion, was not exactly wrong. Carbohydrate-rich foods certainly do increase insulin levels to a greater extent than the other macronutrients. High insulin certainly does lead to obesity.

However, the hypothesis stands incomplete. There are many problems, with the paradox of the Asian rice eater being the most obvious.

… Indeed, many primitive societies that ate mostly carbohydrates have low obesity rates. In 1989, Dr. Staffan Lindeberg studied the residents of Kitava, one of the Trobriand Isands in Papua New Guinea’s archipelago – one of the last places on Earth where people ate a largely traditional diet. Starchy vegetables, including yam, sweet potato, taro and cassava, made up the basis of their diet.

It isn’t foods that raise insulin that make us fat, Fung explains in the following chapters. It’s foods that lead to insulin resistance. Once we become insulin resistant, the entire hormonal system goes out of whack. Fung spends the next few chapters describing the foods that likely make us insulin resistant (sugar being a primary culprit) and how insulin resistance makes us fat.

Insulin resistance is largely about what we eat. But rolling back the effects – and perhaps preventing insulin resistance in the first place – is also about when we eat. That was the most useful message in the book for me, since I’ve already read rather a lot about the effects of foods.

As Fung explains, insulin is supposed to rise after meals. But then it’s supposed to drop and stay low for several hours. Back when few Americans were overweight, that’s what happened — because we ate three meals per day, period. Now we add constant snacking into the mix. When I was shooting interviews for Fat Head, Dr. Eric Oliver, author of Fat Politics, said that while people like Morgan Spurlock want to blame obesity on restaurants for serving larger meals, the real problem seems to be how often we eat between meals. Fung explains why that’s such a problem:

The balance between the fed state (insulin dominant) and the fasted state (insulin deficient) has been completely destroyed. We are now spending most of our time in the fed state.

… We are taught to eat the moment we roll out of bed. We are taught to eat throughout the day and again just before we sleep. We spend up to 18 hours in the insulin-dominant state, with only six hours insulin-deficient.

A lousy diet, of course, makes snacking irresistible. Refined carbs jack up your blood sugar, and your body responds by flooding your bloodstream with enough insulin to give you low blood sugar. If you work in an office, I’m sure you’ve seen exactly what Fung is describing. I see people eat their white-bread sandwiches at noon, and by 3:30 they’re back in the cafeteria, trying to decide if they should raise blood sugar with a candy bar, a bag of chips, or some microwaved popcorn.

Fung describes this as the vicious cycle that leads to insulin resistance. When insulin is too high, too often, cells down-regulate their insulin receptors. Then the body cranks out more insulin to try to lower high blood sugar. Then we get fatter. And hungrier. And snack more often.

Part of the cure is real food, and Fung devotes a good chunk of the book to the topic. But another part of the cure is to dial back insulin resistance through intermittent fasting. As you know, I’m a fan of the Wisdom of Crowds. Fung reminds the reader that in nearly all ancient cultures, periodic fasting was considered a boon to good health. It was part of their wisdom.

In the final chapter, Fung lays out the why and the how of intermittent fasting. Here’s part of the why:

To break the insulin-resistance cycle, we must have recurrent periods of very low insulin levels. But how can we induce our body into a temporary state of very low insulin levels?

We know that eating the proper foods prevents high levels, but it won’t do much to lower them. Some foods are better than others; nonetheless, all foods increase insulin production. If all foods raise insulin, then the only way for us to lower it is to completely abstain from food. The answer we are looking for is, in a word, fasting.

In the rest of chapter, Fung describes the hormonal effects of fasting and dispels the many myths about going without food … such as “it will depress your metabolism.” Interestingly, the research he cites here and in other chapters shows that while living on a low-calorie, low-fat diet will indeed slow down your metabolism, periodic fasting doesn’t. Apparently we’re built for it. Given that paleo man’s hunts weren’t always successful, that makes sense.

Jimmy Moore and Dr. Fung are co-authoring a book titled Fasting Clarity that’s scheduled to be published later this year. I’m looking forward to reading the expanded version of this topic.

In the meantime, The Obesity Code is definitely worth adding to your library of diet and health books.


78 thoughts on “Review: The Obesity Code

  1. Rebecca Latham

    I bought the book. But before I got it and devoured it, I used Dr. Fung’s method of intermittent fasting to lose twenty pounds of body fat in 90 days. During that time, I did not lose lean mass. I got very used to fasting and felt comfortable with it. I reached normal weight, reduced my blood glucose to normal levels, lost a bunch of visceral fat, probably cured non-alcoholic liver disease and no doubt kicked my insulin resistance to the curb.

    I can’t recommend his book enough. Thanks for the great review, and I hope it convinces a lot of people to read it!

    1. Tom Naughton Post author

      I find that after switching to a low-carb diet, fasting is no big deal. I ate dinner about an hour ago, and it was my first meal since the previous night’s dinner. I do that once or twice per week now.

      1. Jennifer Snow

        I picked up the book. Lot of very interesting things in there. I solidly second your recommendation.

        Also, I’m trying fasting now–I don’t eat at all for 2 days a week, and I eat only one meal (at dinner time) the other 5. I’m hungry, but not bad, and I have LOADS of energy and I feel really awake/alert.

        1. Tom Naughton Post author

          Good point. We need to learn to distinguish between occasional hunger pangs and a real need to eat.

    2. Dave Coolman

      I agree. I’m down 30lbs in the last two months (not meant to out do you, I was way overweight so have a lot to lose.) His chapter calling out so many diet solutions as “eat more to lose weight” hits home now that I’ve relinquished the urge to force eat three meals a day.

      I think it’s also vital to read the book–because despite the fact that the people I work with have noticed and called out how well it’s working, they think I’m crazy that I just “skip meals”. I think if my co-workers read Dr. Fung’s explanation of the physiological science, it would seem less daunting.

      It is a credit to Dr. Fung how readable this book is for how complex and challenging the topic can be.

    1. Tom Naughton Post author

      Sure, I’d point to them as evidence that a diet of whole-food starchy carbs doesn’t make people fat, but not necessarily as the picture of health. From what people have said in comments, they’re enthusiastic smokers.

    2. donny

      I’m by no means a “carb lover”, I’ve been eating a low carb diet for over a decade. But–a group with a high child mortality rate, but with a life expectancy of 75 years once they’ve reached 50, doesn’t make for a good criticism of their diet–to me it’s more a suggestion that they probably don’t have access to some other modern amenities, maybe their environment isn’t as sterile as ours and young people are being lost to infection, maybe they don’t have as much access to modern health care as would be best.

      Having said that, I guess a low protein intake or low fat could plausibly contribute to a high mortality from infection in young children. In places with even lower animal protein intake, often the adults are mostly doing just fine, it’s the young kids that suffer from protein deficiency.

  2. Kanor

    Jimmy and Dr. Fung’s book is titled The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting.

  3. Leslie Thompson

    I have been following Dr. Fung’s low-carb teachings since January and his intermittent fasting protocols since the beginning of June. I have lost just over 45 pounds in 6 months. I agree with you as well, Tom, once you are on a low-carb diet, fasting is easy. I only eat once a day.

    By the way, Tom, I watched Fathead and truly loved it. It was concise, honest and very funny. Can’t wait to buy the new children’s book you have coming up.

    1. Tom Naughton Post author

      Thank you. It’s slow going on the book because we want it to be very cartoony and fun for kids. So of course, I keep thinking up more cartoons for Chareva to draw. But we’ll get ‘er done.

  4. Anand Srivastava

    Looks like the most plausible reason for obesity is not fasting. No wonder all cultures prescribe some form of fasting via one pretext or the other.

      1. Jennifer Snow

        Dr. Fung points to insulin resistance caused by insulin levels that never drop low as the main culprit. Getting your blood sugar down won’t do you any good if you don’t also drop insulin levels.

        1. Jennifer Snow

          He also points out that a lot of things can have a profound effect on your insulin that don’t raise your blood sugar.

        2. Walter Bushell

          In fact tight control of blood sugar by increasing insulin was found to be counter productive. The Accord trial was the first and others followed. Trying to control insulin in Type II is like balancing an eel on the end of your nose. In the end you end up with Type Ii and Type i, if you follow mainstream advice.

  5. Tom Welsh

    Thanks for this really useful and interesting post, Tom. I had been unsure about Dr Fung’s book, but now I think I’ll buy a copy.

    “Proofreader” department:

    “Given that paleo man’s hunts weren’t already successful, that makes sense”.

    I think that should be “always successful”.

  6. Tom Welsh

    Hey Tom, I hope you will forgive this off-topic question. But it has really been haunting me. Remember this study? The Scottish guy who fasted under medical supervision for 382 days with no apparent ill effects?

    Apart from the many other questions the study raises, this really has me baffled. Everyone alleges that the human brain needs glucose, and a lot of it, to go on working. And if it stops working for 5 minutes, you die. So if you go on a low-carb or no-carb diet, the liver steps in with gluconeogenesis and turns protein into glucose. So far, so (fairly) good. Although I have always wondered how that glucose gets all the way to the brain without being snarfed up by other hungry tissues. Does the liver attach little notes to each molecule, like the ones you might put on your sandwich in the office fridge? “This glucose belongs to THE BRAIN! Do not consume unless you want us ALL TO DIE”.

    Now, here’s the real blockbuster. Gluconeogenesis changes protein into glucose, so as long as you are eating sufficient protein all is well. Some for the brain’s glucose ration, some for essential repairs, etc. But what happens when you fast for over a year? Apparently the liver must consume all of the body’s lean tissues several times over in order to maintain gluconeogenesis. Or the brain dies. Yet the young man in the study ended his 384-day fast with both a working brain and normal lean tissue.


    1. Tom Naughton Post author

      Dr. Fung wrote about that guy in the book. Fat is formed into triglycerides (three fatty acids, one glycerol) when stored as body fat. According to Dr. Fung, the glycerol is converted to glucose when the fat is released and burned. Ketones substitute for much of the glucose burned by the brain.

      Can’t say I’d recommend such an extended fast for anyone who isn’t seriously obese.

      1. Tom Welsh

        I hasten to reassure you that I am not planning to fast for more than a few days – maybe a week at the outside, but right now it’s only 40-48 hours. My question was, if you like, “academic” but I don’t think that word is quite adequate. The thing is that my question seems to be more or less unanswerable in the framework of the little I have learned about human biochemistry.

        In his excellent book “The World Turned Upside Down”, Dr Richard David Feinman asserts that the brain requires a minimum of about 50g of glucose per day (when ketone bodies are available during a fast). But the only source of glucose he mentions is gluconeogenesis. Then again, his book is not a systematic textbook but more of a speculative wander around the interesting issues of biochemistry as related to nutrition. Rather like his blog (and Dr Kendrick’s). One thing that Feinman does stress is that (with a few exceptions which he does not state) the body can turn glucose into fat but cannot turn fat into glucose. I am surprised that he does not mention the “glycerol to glucose” pathway.

        Damn it, I may actually have to study and learn a little basic science!

        Thanks for your answer, which is helpful. I’ll read Dr Fung’s book and see his detailed explanation.

        1. gallier2

          I am surprised that he does not mention the “glycerol to glucose” pathway.

          It’s not even the only fat->glucose pathway. There’s also the acetone reclaiming pathway. Chris Masterjohn had nice article on it some years ago.

          I find it fascinating how that discovery is ignored, even from low-carbs proponents. The evidence is quite compelling and it would be really nice if a quantitative assessment could be made to see if that pathway is as negligible as everybody seems to think or that it requires some time to adapt (what I think) before it is able to take over a good part of the glucose needs (the observation that people going on ketosis have acetone breath at the beginning and not after some time goes in that direction).

  7. Chris

    Interesting how the 5:2 diet and low carb/insulin diets are all coming together – people have assumed they work for different reasons, but perhaps not

  8. Steve Ward

    Tom, I think you meant to say ” hunts weren’t always successful” not already…or did I misread something somewhere else?

    1. Lynn

      I also have tried the 5:2 diet with little positive results. Maybe we went too wild with food when we were not fasting??? I tried not to…

  9. Elenor

    I sort-of intermittently fast unintentionally: I’m not hungry till late in the day after my coffee with cream and a bit of (unsweetened) almond milk, but I’ve read a bunch of ‘warnings’ that IF and women don’t mix well? I’m ordering the book, which I hope will provide info (and of course, I’m using your Amazon link, Tom! {wink}) but did you get / do you have a sense about the warnings for women (or it is for women of child-bearing years? or ??) around IF?

    1. Tom Naughton Post author

      He didn’t mention it being less effective for women, but I couldn’t say. Perhaps he’ll cover that in the upcoming book.

      1. Walter Bushell

        In “Fasting Part 1” there is a drawing of a doctor advising a patient “Let’s ease into this — I want you try fasting between meals.”

        Even that would go a long way for many people. Including the patient who is obviously morbidly obese. Especially as typical snacks are high carb and beyond that high fructose.

    2. Tom H.

      That’s why the entire population of Muslim women dies off during Ramadan – women just can’t fast. /s
      (JIK you don’t know: Ramadan is a month of fasting in the Muslim religion – adherents are not allowed to ingest anything from sunup to sundown. No food, no water. There are exceptions for children, women who are pregnant or breastfeeding, and the ill)

    3. QT

      Dr. Fung just wrote an article this month (June 11 and 22) through the DietDoctor blog called “Women and Fasting” basically saying, with the exception of pregnant women, underweight women, and women with special medical conditions, there is no reason women cannot and should not fast. “Consider the past 2,000 years of human history. Are Muslim women ‘exempt’ from fasting? Are Buddhist women ‘exempt’ from fasting? Are Catholic women ‘exempt’ from fasting? No. So we have millions of person-years of practical experience with women and fasting. And there are no problems in 99.9% of cases.” Full article at

  10. Kelly

    So, wait a minute – all that talk about “eating every 2 hours” to “keep your metabolism fired up” is just plain wrong? This is seriously news to me and also makes a lot of sense. Does the book give any guidance on fasting the proper way, or do we have to wait for the new book?

    Also, what do you think of other research that shows IF is NOT necessarily the way to go, especially for women, in light of the message of this book.

    1. Tom Naughton Post author

      Yup, he says eating every two hours doesn’t give you faster metabolism, but can make you insulin resistant. There are instructions for fasting in the appendix.

      I’m not sure if it’s less-good or bad for women. I haven’t seen any research to that end.

  11. Dianne

    Sighhhh. When I was diagnosed with hypoglycemia, back in the sixties when it was the disease du jour, the prevailing medical advice was never to let your blood sugar drop at all — just keep eating multiple small meals and snacks all day long. I followed that advice religiously for decades, and would also snack if I woke up at night. Maybe my life would not have been any different if I’d stuck to three meals a day, period, but I kinda wish I could turn the clock back and find out. I can at least find out what will happen in the future if I do IF, though it’s possible my metabolism is too thoroughly trashed by now to make a big difference. At the very least, I hope that young people who are searching for pathways to better health and more sensible eating will take Dr. Fung’s advice to heart.

    1. Tom Naughton Post author

      Dr. Fung gives the “eat all day to keep your blood sugar up” a pretty good smackdown.

  12. Kathy

    Excellent review. I am also following Dr. Fung’s protocol. The revelatory moment was when I realized that no matter how great I am at following a low carb, high fat, diet — it would not necessarily fix my insulin resistance. I have been struggling for 40 years with diets with little success, and only the intermittent fasting has moved the scale. Once you learn how to fast, the level of energy you have increases exponentially. So even though I still have quite a bit of weight yet to lose, I’m working out at a gym and doing a lot more activities — while in a fasted state. It’s simply amazing. I so wish I had learned about this years ago.

    1. Tom Naughton Post author

      Like you, I didn’t feel my energy dropping while fasting. Some belly gurgles, but none of that light-headed “must eat now!” feeling.

      1. Firebird

        That is where IF has failed me. I get those belly urges and I HAVE to eat. I simply cannot ignore it.

        1. Tom Naughton Post author

          The belly gurgles don’t bother me. They’re just noise, maybe with a minor hunger pang. It’s not the same for me as that weak, shaky, “must eat now!” feeling I’d get when, say, having a Slim-Fast for breakfast and then trying not to eat again until lunch.

  13. WereBear

    I love the book and have successfully shifted to one meal a day, 2-3 in the afternoon. As a bonus, that one meal I day I eat tastes so incredibly good! And I choose carefully; high nutrition means high flavor.

    While I have read that women have a different hormone profile from men, and thus fasting is different for them, I am IFing to FIX my hormone situation: a few years of the menopause from hell and no help from the medical profession means I can fast now. When I was at my sickest, I could not.

    1. Tom Naughton Post author

      I like that Dr. Fung also says in the book that it’s okay to feast now and then. I find a couple of 24-hour fasts during the week and feast on Saturday night works quite well for me.

  14. Deb

    To those who are concerned about IF for women, Dr. Fung recently posted an article on his “Intensive Dietary Management” site which poked serious holes in that particular theory. I am one of those females who has used IF in conjunction with a LCHF or ketogenic diet, and had excellent fat-loss results, as well as feeling terrific! Most people worry about their energy levels, and I can tell you that, for me, they skyrocket! (If you are eating a high-carb diet, I imagine it would be harder to make the transition to fasting than if you are fat-adapted.) Dr. Bert Herring also has a great TED talk on the “Fast 5” Diet, about compressing your eating window into five consecutive hours, which is another form of IF.

    1. Angel

      Fasting being a problem for women isn’t a theory, it’s a concept floating around in the blogosphere because a lot of women have reported having problems with fasting. I am one of them. I am hypoglycemic and fasting really messes up my blood sugar, raising my cortisol, and probably other issues as well. I wish I could read a book and understand what the ultimate issue is; I would love to normalize my insulin response and lose the last 20 pounds I need to lose. But I can’t fast, and I can’t do low carb or ketogenic diets either. All I can do is keep reading and hope to find some answers eventually; the conventional medical establishment certainly will never be of any help.

      Women in general do have different metabolisms than men. That’s why it is so important that metabolic research include women as subjects, although I’ve yet to hear of any research being done on women who can’t fast.

      1. Lori Miller

        I can’t fast, either, unless my stress level is really cranked up. I get tired, my head hurts, and I get hungry enough to eat the wallpaper. Going very low carb gives me scary palpitations, and I can hardly take potassium pills fast enough to get rid of them. A carb level between Atkins maintenance and The Zone works for me.

        1. Walter Bushell

          Belike you need more salt. If salt goes too low, potassium is excreted fast.

          Remember on low carb you are getting much less sodium because you are not eating junk food and insulin is lower so you excrete more.

          Stephen Phinney and Jeff Volek — _The Art of Low Carb Living_ and also the Youtube video Stephen Phinney made.

  15. The Older Brother

    Well, knowing this review was coming, I’d resigned myself to another purchase.

    Then, low and behold, I got an email from Barnes & Noble that somehow, Apple had screwed me over on my eBook purchases somewhere back in time and I had a credit for 20 or 30 bucks on my account! This seemed strange as I didn’t own any Apple devices back then, and I never, while voluntarily hitting the “purchase” button for another nook book, had the sense that I was paying more than I should have to. Because if I thought that, I wouldn’t have hit the button.

    Anyway, since it seems almost like free money, this seemed like a good way to use it up. Thanks Steve Jobs, wherever you are.


      1. Robyn

        Especially because people outside of the US who also bought ebooks during that time (I think the issue was collusion to increase prices or something) don’t get a single cent back.. I was spending $1000s of dollars on ebooks back then.. ripped off!

  16. jackisback

    I know I am supposed to buy the book… (and I will since I have become a collector of low-carb-ish books), but I am dying to know what other foods Dr Fung suggests promote insulin resistance. Sugar is no surprise. The usual suspects? Grains, legumes?

  17. Andy Lopez

    No one with a functional pancreas has “insulin deficiency”.

    What they have is Normalized Insulin, Homeostatic Insulin or Optimal Insulin.

    Only people with disfunctional or non functioning pancreas beta cells that cannot make insulin have “insulin deficiency” and even they don’t because they can inject it.

  18. jillm

    Very interesting. Thank you Tom. Fasting is an ideal argument for people who say they can’t afford to buy nourishing food. In a recent supermarket catalogue: Corn chips were the equivalent of $23.10kg. Beef blade roast was $11kg.

    1. Walter Bushell

      You can imagine the profit$ on those corn chips. There may be more money spent on packaging and advertising than on the ingredients. The beef costs more to start and needs to be refrigerated and sold timely whereas the chips can last for decades.

      Now imagine the profit$ from Chocolate Coated Sugar Bombs.

  19. SWOT

    I have no problem with short term intermittent fasting. It’s a great insulin lowering hack, and I agree it can help improve insulin sensitivity. Where I think Fung is full of cacky is when it comes to longer term fasting.

    First he uses Kristina Varaday’s–she does the alternate day fasting studies that that BBC reporter michael mosley 5:2 diet is based on–as “proof” IF doesn’t cause lean tissue loss..

    It does after about 72-96 hours. Varady’s study only cover 24-48 hour fasting.

    Leptin levels, and by consequence Thyroid, SNS, start to plummet after 3-4 days and by 7 days are typically 50% what they were before caloric restriction started. That’s a recipe for post-dieting weight rebound and then some.

    Jimmy Moore lost 50% of his weight as muscle if I recall when he was doing 30 days of Fung’s fasting.

    So if you want to IF, don’t go more than 72 hours. Then eat maintenance for at least 72 hours before you resume since it typically takes that long for leptin levels to rise back up after caloric restriction

    At least Lyle McDonald gets it right in that regard: see Lag Time Between Drop in Leptin and Metabolic Adaptation

    1. Tom Naughton Post author

      I’ve never tried a fast lasting longer than 36 hours and don’t see a good reason to go beyond that.

      1. SWOT

        Agreed. In addition most of the benefits of autophagy like better brain function from BDNF, etc. are in full gear by 20 hours, and you don’t benefit much beyond 48-72 hours too from that as well.

        Actually, there is a slight spike in metabolic rate at about 24 hours from SNS activation, more ephinephrine/norephinedrine, etc. trying to create energy from body reserves, but again, you are back at baseline by 72 hours and it’s downhill from there.

  20. Alan


    Thanks for this post. I have used IF in the past to lose weight quickly, easily, and in a much safer way than a diet pill ever could. I’ll have to get this book. So are we to believe that cultures that eat their share of pasta/bread that have lower obesity rates than the US have regular fasting? I just read the laughable ‘French Women Don’t Get Fat’ and it of course recommends just eating this stuff in ‘moderation’. I am inspired to add IF back into my diet thanks again

  21. Elaine Davidson

    I’m 1/3rd of the way through Dr Fung’s book and find myself constantly nodding my head in reaction to all the good info he’s writing to us. So glad to read your review, Tom. Also glad to report that since the Low Carb Cruise I’ve been eating a very clean keto diet and have temporarily stopped dairy except for butter and ghee and no sweeteners of any kind. I coupled those choices with stopping any eating after 6-7pm. My fasting blood sugars have been perfect and am happy to report that I am exactly 15 lbs down since we got back from that great vacation.
    Thanks for the great review!
    p.s. my friend and I rented FatHead on iTunes and watched it tonight, great job friend!

  22. Zachary

    It’s so nice to come across information that’s actually enlightening and life changing even after studying this subject for almost 10 years. I’ve always known about fasting, but I just thought of it as something to add to your health benefits, not something that might be essential to the control of insulin resistance. Jason Fung describes fasting in a way that I never really thought of when it comes to thinking about controlling insulin and not just blood sugar, and the fact that any food can and will raise insulin and that abstaining from food is a surefire way to lower and stabilize it. I began an 18 hour intermittent fasting protocol with a 6 hour eating window, and already I find the stubborn belly fat that I have never been able to burn (even on a low-carb whole foods ancestral diet with zero refined carbs) starting to go away. Thank you so much for this book recommendation!

    Jason Fung also has a great 6 part lecture on youtube titled The Aetiology of Obesity. It goes through mostly everything that was in the book, but I still find it worth checking out.

  23. Underground

    It’s interesting how this seems to play into not just “what” we eat, but “how” we eat it. A further reflection of millions of years of development?

    Biology developed around patterns of behavior punishes us for swinging outside that window. Three hours of sleep, subsisting off a steady diet of snack cakes, fried starch and sugared drinks, and being inactive. Probably just a tad outside that threshold.

    Simplicity. But so often (certainly not all to their credit, some actually listen) when I go to a doctor it seems a first reaction is making the symptoms => medication association.

  24. Neelesh

    Hi Everyone, This is Neelesh from India. Very recently came across Dr. Fung’s book.

    I am suffering from hypothyroidism from last 3 years and gained almost 16 kg weight. Tried many times low calorie diets in addition of strenuous exercise. I didn’t help me at all.

    Now very excited to start the IF for at least one months.

    Interestingly, Dr. Fung didn’t mention anything about the connection of weight gain, hypothyroidism and insulin resistance. I will be glad if anyone of you have any idea.


  25. Chantal Black

    Im wondering about something, keeping in mind that i have not read the book and did not read this entire thread-my eyes are tired haha…

    a friend told me she had read this book and is working on losing her weight using these principals-i applaud her for that…

    my son is a type 1 diabetic and i wondered (having seen diabetes mentioned somewhere above, forgive me if someone went into more detail, as i mentioned i didn’t read every post) I wondered-if he were to take his insulin regularly (he is 27 and a stubborn diseased (so sick from diabetes that he simply cannot compute how sick he really is) shit that i have to pray for ever bloody day since i can’t pin him down and jab him four times a day with insulin pens…)

    if he were to take insulin regularly, would he get fat? or is this different in people whose body’s do not make any insulin at all? and whereby the only insulin they get is controlled….(i think i may have actually answered my own question)

    ultimately, the gentleman was referring i am guessing to type 11 diabetics who had complained the insulin made them fat….

    1. Tom Naughton Post author

      Several studies have demonstrated that people on high doses of insulin gain more weight than people on lower doses. But if your son is type I, my guess is that he’s simply injecting the amount of insulin his pancreas would otherwise be making. It’s type II diabetics who often inject higher and higher doses of insulin in order to overcome the insulin resistance.

  26. Deborah

    I found The Obesity Code to add the final bits of revelatory information that I needed, despite having low-carbed for 16 years now, and having read all the usual LCHF books (Taubes, Teicholz, etc). Although I lost 100 pounds initially when I started low-carbing, I gained 30 through pregnancy, and then nothing but nothing helped me shift them, despite continuing to low-carb. And over the years, the frustration of that situation led to less control over my eating, and more splurges, which led to yet more weight gain. And all this while still eating low-carb 99% of the time! The splurges were very rare. But over 8 years, it led to another 25 pounds gained. I was getting desperate and even considering bariatric surgery, since lchf just wasnt’ cutting it anymore. And then I read the Obesity Code. I’d known about intermittent fasting, but this laid out the science behind it. And the fact that insulin is raised by sweeteners. It was tough to start – tough to quit all sweeteners, for one thing, but in the past few months I have lost 25 pounds and am on my way to getting back to where I once was. IF is infinitely flexible, you can change it depending on what’s going on in your life in a particular week. I usually do 2 24 hour fasts and 1 36 hour fast a week, although recently broke a stall by doing slightly longer fasts. I also have terrible stomach issues – throwing up, severe trapped wind, even fever – during menstruation and that almost disappears as long as I don’t eat. So I do longer fasts around that time. I was so, so fed up with gaining weight while still eating LCHF 99% of the time… Dr Fung gave me back hope.

  27. Debbie

    A couple of questions please –
    When referencing a “low carb diet” – how to equate with difference between simple & complex carbs?
    With the prolonged (anything over 16 hrs) how does the value of adequate nutrition for optimum health factor in – in other words , are proponents of this as a healthy lifestyle believing nutrition optimum scan be achchieved?

    1. Tom Naughton Post author

      Yes, but if you’re eating less often, you want to make sure you’re eating nutrient-dense foods. I don’t separate carbs into simple and complex; I separate them into processed and non-processed. The processed carbs spike glucose much faster and are the ones to avoid. Non-processed carbs from real foods are usually more nutrient-dense and don’t (most of them, anyway) spike blood sugar so quickly.

  28. JCHris

    Thank you for all the information. I hope to get some insight:
    I am a vegetarian and will stay one. The Paleo Diet is not doable for me. Is it useful for me to buy Dr. Fung’s book?

    1. Tom Naughton Post author

      Yes. You’ll want to understand the biochemistry, whether you’re a vegetarian or not.

  29. Olga

    That nice to read all this comments , sound promising, so I did start my starving and looking forward to have result to loose extra fat and became pretty and healthy!


Leave a Reply

Your email address will not be published. Required fields are marked *