Book Review: The Obesity Code by Jason Fung MD

book by:
Jason Fung MD

Reviewed by:
On March 28, 2016
Last modified:July 22, 2016


In this important book, Dr. Fung takes aim at tired myths about weight control and shoots each of them dead, right before your eyes. He convincingly argues that obesity is a hormonal disorder that can only be conquered by eating in a way that brings hormones into balance.

The Obesity Code by Jason Fung, MD

I love this book.

The Obesity Code eats most other weight loss books for lunch, without gaining an ounce.

When Dr. Jason Fung asked me to review his new book, The Obesity Code: Unlocking the Secrets of Weight Loss, I eagerly agreed, and I’m delighted to say that his book truly exceeded my expectations.

Dr. Fung argues that obesity is not about calories or fat grams or exercise, but about hormones. The main character in his book is insulin, a powerful hormone that regulates our metabolism. When insulin levels run too high for too long, we develop “insulin resistance,” which can make us fat. By identifying the true culprits in obesity, Dr. Fung provides readers with much-needed hope and strategies grounded in science rather than mythology.

Dr. Fung is a nephrologist (kidney specialist) practicing in Toronto, where he founded the Intensive Dietary Management program. His signature prescription for patients with obesity and type 2 diabetes is his intermittent fasting protocol. While I’ve yet to have the pleasure of meeting Dr. Fung in person, we are connected via a growing network of clinicians who study the health effects of low-carbohydrate diets. We are also both members of Physicians for Ancestral Health, a group of doctors interested in the application of whole foods diets to common diseases. Dr. Fung is considered one of the leading specialists in intermittent fasting, a topic I knew little about prior to reading his book.

Even if you have absolutely no interest in fasting, you’ll learn all kinds of wonderful things that will completely change the way you think about food and weight. You will emerge armed with powerful information about your health that you can use to improve almost any diet and help you reach your health or weight loss goals.
SodaStream (Soda-Club) USA
Dr. Fung has chosen to focus squarely on obesity, but the story he tells of how food can damage our delicately balanced hormonal networks has implications for all of us, no matter how much we weigh. This is because insulin resistance is about so much more than obesity and diabetes—insulin resistance is nothing less than the driving force behind most “diseases of civilization,” from heart disease to cancer to Alzheimer’s disease. Therefore, even if your weight is normal, you can still have insulin resistance, putting you at risk for serious health problems down the road. If you fall into any of the below categories, this book is for you:

  • Do you gain weight easily?
  • Do you gain weight even though you exercise religiously and don’t overeat?
  • Do you have trouble losing weight, even on a low-carbohydrate diet?
  • Do you want to prevent or reverse pre-diabetes or type 2 diabetes?
  • Are you curious about fasting as a weight loss strategy?
  • Do you have an insulin-resistant condition, such as Pre-diabetes, Fatty Liver, Polycystic Ovarian Syndrome, “High Cholesterol”, pre-Alzheimer’s, or Erectile Dysfunction?
  • Are you a health professional who needs to understand how to help people lose weight?
  • Do you want to know which foods are most damaging to your metabolism and overall health?

Obesity is a Hormonal Problem

For decades we were (mis)taught that low-fat, low-calorie diets, in combination with exercise, are the key to maintaining a healthy weight. Yet, the tired, impotent mantra of “eat less, exercise more” has betrayed countless overweight people. How many people do you know who have worked hard their whole lives to control their weight without any lasting success? On the other hand, we all know people who maintain a healthy weight without having to count a single calorie or ever get up off the couch. Overweight people are hormonally different.

Dr. Fung’s writing style strikes just the right balance, providing enough rock solid research to convince even the most skeptical physician of his argument, without overwhelming or boring a general audience. He takes readers by the hand, leads them out of the confusion about dieting and weight loss, and into the light: obesity is a hormonal disorder of persistently high insulin levels and insulin resistance, caused by eating the wrong foods too often. If your insulin levels are too high, no matter what diet you are following, and no matter how much you exercise, you will gain weight.

I have read a great deal about the relationship between insulin and obesity, so I was pleasantly surprised to see that Dr. Fung tells the insulin story in a uniquely compelling and convincing way. He assembles a firing squad of fascinating facts from history, medicine, politics, science, and human experience, takes aim at all the useless myths about weight control, and unceremoniously shoots each of them dead, one by one, right before your very eyes. Even though the insulin-obesity connection is one I already understood very well, he explains it so beautifully and from so many different angles, that I was riveted.

For the throngs of people who haven’t yet been introduced to these ideas, this book will be nothing short of a miraculous revelation. Dr. Fung provides people who have been struggling with weight their whole lives with precious “Aha!” moments that will finally relieve them of the guilt, shame, and demoralization that can come with failed attempts at weight loss, and empower them with the information they need to succeed.

Dr. Fung explains exactly why losing weight is so hard for overweight people. He addresses all of the following questions, and more:

  • Why does metabolism slow down as we get older?
  • Why does the body resist weight loss?
  • What drives yo-yo dieting and the weight roller coaster?
  • Why doesn’t exercise work as well as we think it should?
  • Why are children and even babies now becoming fat and diabetic?
  • How does stress contribute to weight gain?
  • Are some carbohydrates more dangerous than others?
  • Does it matter how much food you eat in one sitting?
  • Can eating too much protein interfere with weight loss?
  • Are all calories created equal?
  • How can low-calorie sweeteners make it harder to lose weight?
  • Is breakfast really the most important meal of the day?
  • Why doesn’t fat make you fat?

The Obesity Solution

How can you correct your hormonal imbalance? Dr. Fung believes that you must dramatically change not only what you eat, but when you eat.

The fastest way to dramatically lower your insulin levels is to simply stop eating. This is why the cornerstone of Dr. Fung’s approach is to fast several times per week. He educates and reassures readers about his approach: he writes about fasting traditions in human history, how fasting affects hormones, how to cope with potential side effects, and (curiously) what you can eat and drink during your fast.

What should you eat when you’re not fasting?

Unlike many other low-carbohydrate advocates, Dr. Fung emphasizes the importance of eating real, whole foods. In this way, he demonstrates that he cares not only about your weight, but also about your overall health.

While there are no recipes or menus in the book, he does provide a couple of sample weekly meal plans to give you an idea of what his approach looks like. He doesn’t prescribe a particular number of calories, carbohydrate grams, or protein grams; instead, he sets forth five basic principles to guide your food choices. This means that you can apply his philosophy to most diet plans, from plant-based to Paleo. He provides a great deal of information about specific foods and how they affect your metabolism, including surprising tidbits about fiber, vinegar, and dairy products, just to name a few.

Wish List

I agree wholeheartedly with the lion’s share of the ideas within this book, and thus my criticisms are minor.

The diet he proposes is extremely healthy compared to the average diet, but his sample menus do include whole grains, legumes and dairy products. Although he emphasizes that his menus are only suggestions and can be modified, I was surprised to see dairy products on the table, as dairy products have powerful effects on our metabolic hormones. Dr. Fung sends a somewhat mixed message about dairy. He warns people against consuming whey protein, because it triggers insulin spikes, yet encourages the consumption of full-fat dairy products, citing primarily epidemiological studies to support this recommendation. [Yet, he does a beautiful job in his chapter entitled “fat phobia” of calling out epidemiological studies as dangerously misleading.] As most of you know, I put virtually no stock in nutritional epidemiology, and I believe that grains and legumes pose health risks for humans. Therefore, I would simply recommend that people who choose to follow his dietary protocol avoid grains, legumes, and dairy products.

I have never tried intermittent fasting myself, so I can’t comment on what it’s like or how it compares to my own strategy, which is a high-fat, adequate protein, very low-carbohydrate ketogenic diet. A ketogenic diet is also very effective at lowering insulin levels, and does a beautiful job of reducing appetite. For people trying to understand which of these approaches is right for them, I wish that Dr. Fung had shared his thoughts on how these two plans compare, particularly when it comes to questions of metabolic adaptation, hunger, and stress hormone levels.

Dr. Fung emphasizes that the stress hormone cortisol causes weight gain. I wish that he had addressed the question of whether fasting triggers an increase in cortisol levels, which is a common concern in the blogosphere. I also would have loved some case examples from his practice showing us how his patients respond to intermittent fasting—insulin, cortisol, blood glucose, appetite, and weight trends over time would all be fascinating parameters to observe.

I also wish he had shared with us his perspective on the question of why women tend to gain weight more easily than men, since this would seem to be another phenomenon signifying that obesity is a hormonal disorder.

Lastly, Dr. Fung makes the case that fructose is worse than glucose when it comes to the development of insulin resistance, but in my deep exploration of this topic in a series about fructose I wrote last summer [Has Fructose Been Framed?], I was unable to find evidence of this except in studies of pure fructose (which doesn’t exist in nature) at extremely high doses.  [The clinical experiment he referenced in his fructose chapter used 1,000 calories per day of pure fructose, and therefore lies within this exceptional category.]

Bottom Line

In my view, insulin resistance is Public Health Enemy Number One, and The Obesity Code is the most complete and most satisfying book about insulin resistance I have ever read. I am so glad to finally have a physician-authored, science-rich, accessible source to recommend to my colleagues, friends, family, and patients that explains so clearly what we all need to know about this massively important topic. Go ye forth, read, and be…ahem… enlightened.

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  • Cyndi

    Thank you for the review. This book has been on my radar; though I’ve easily maintained my 25 lbs weight loss for two years by strictly sticking to a low carb / high fat diet, the topic and understanding the mechanisms of lowcarb (in all its abundant diet versions) is interesting. Dr. Fung’s interviews via Jimmy Moore on the Livin la Vida Low Carb podcast are quite informative too.
    Your blog is inspiring, Dr. Ede. Though my diet is not exactly like yours, you sharing your work and experience helps me feel confident in my own less conventional diet; such as, I don’t eat fruit.

    • Hello, Cyndi

      Thanks for writing in! Yes, his message is about so much more than weight–it’s really about metabolism and understanding how our hormones “think.” I wish more people with insulin resistance felt comfortable letting go of fruit, and I’m so happy for you that your diet is not exactly like mine:) It’s wonderful that you have had such health success with LCHF–congratulations!

  • George

    Thank-you for the review, it was quite timely as I just heard about Dr. Fong at He has a short CBC radio interview that can be found at
    Formally having been a breakfast skipper I was eating it regularly since was encouraged and an easy low-carb meal. As a result of Dr. Fong ideas I am now dropping breakfast and will have my breakfast bacon and eggs for lunch on the late side instead – the big mental leap – having breakfast for lunch.
    Now to get the book and better understand it all.

    • Hi George

      Thanks for sharing the tip! Yes, for other readers who haven’t heard that recommendation, one of the things Dr. Fung says in his book is that there’s nothing special about breakfast, so if you’re not hungry, there’s no need to eat it. I completely agree!

  • Stephanie

    The Obesity Code is one of the best books I have read. Much of it I already knew from other books and blogs such as yours, Dr. Ede, but Dr. Fung’s explanation of insulin resistance and intermittent fasting was enlightening. I began doing a 16:8 fast which helped me lose a little faster than the 1/2 pound or so a week I usually lose. I was intrigued by his assertion that hunger goes away completely after the second day. On Sunday I had a cup of coffee with cream, then had a busy day planned with nothing ready to eat. I left the house and got home about 3 PM and was no longer hungry. I am keto-adapted so I’m guessing my body just switched quickly to burning its own fat. I skipped dinner but expected to have trouble sleeping on an empty stomach. Nope! I am now in the middle of Day 4 of fasting. My energy level is normal, I am not at all hungry, and my brain seems sharper and more focused. Plus I have lost 4 pounds during the fast. Each day I figure I’ll break the fast at dinner and each day I have felt so good I continue.

    I am so excited. Since I am 64, I was afraid I might never lose enough weight to matter. I believe now that I will easily lose the remaining 40 pounds. I plan to do a 36-hour fast at least once a week and perhaps a multi-day fast once a month. This is life-changing for me. I highly recommend this book to everyone.

    • Hello, Stephanie

      That IS so exciting!! Thank you so much for sharing your experience with fasting with us, as my own experience with fasting consists of a single 3.5 day fast a few years ago, so I don’t have a lot to share with my readers about what it’s like to do it on a regular basis. Like you, I wonder if fasting is generally more comfortable if one is already keto-adapted…regardless, I am really happy for you and wish you healthy success going forward!

  • FromPA

    I’m looking forward to reading Dr. Fung’s book. I’ve read most of his blog entries and viewed almost every video. I started LC diet then realized after losing about 20-25 pounds that I was still insulin resistant. I was still losing weight, but slowly, and I was eating 5+ meals per day (as is recommended). After Dr. Fung’s website visits, I started intermittent fasting (IF), first skipping breakfast two days a week, the breakfast and lunch two days a week, then not eating for a day, then not eating for multiple days. I’ve felt much better and lost another 30 pounds or so. I’ve also increased my fat content to as high as I can eat per day. For instance, I’ll add butter to chicken or fish or add other fat to my meals. I find that after trying IF for about a year, I get less hungry with time, I feel better, and everything has improved.

    As for dairy, I still eat dairy. It’s too far for me to go to not eat dairy. For instance, I’m trying (and I think succeeding) in dealing with IBS-like symptoms and poor biome (including in my mouth), which I think resulted from years of high carb. The problem as I see it is that very low carb might not provide enough prebiotics to repair a broken biome and also not enough probiotics, especially without yoghurt and cheese. It’s possible to get probiotics, but you’re looking at sauerkraut and kimchi and not much else. For dairy, I try to minimize it, but I do eat cheese and cream and yoghurt and sour cream. I eat the highest fat cheese made from raw milk I can find. I make my own yoghurt when I can, from milk from grass-fed cows. I also take in butter oil (100% fat, though) for vitamin K. I’ve also added some potatoes (cooked, refrigerated, then reheated) and some green plantains to my diet, in an effort to increase the prebiotics. Also, I spent years not eating cheese and cream and butter, as I thought these were horrible and deadly. Now, when I can finally eat those, people say they’re bad for me.

    Finally, if dairy is so bad, why do other cultures (such as the French) eat a lot of dairy and have seemingly no problems doing so? I realize that epi studies are garbage, and I agree with that. But while epi studies can’t prove causation, they can disprove it. To me, epi studies indicate that it’s unlikely dairy is bad for people. Of course, the RCTs to prove this one way or the other haven’t been done (too bad they didn’t have a “no dairy” arm of the Women’s Health Initiative trial).

    • Hello, PA

      I agree that different people have different degrees of tolerance for dairy. I personally gain weight when I include dairy in my diet and develop skin problems, digestive problems, migraines, etc. But of course that’s just me. On my dairy page there are references to other clinical problems that some people experience when eating dairy, especially children: Clinical studies of dairy foods and insulin resistance are mixed. There are some clinical studies demonstrating that the addition of dairy increases risk for metabolic syndrome: (scroll down to the dairy section). Regardless of the science, I’m jealous of your ability to tolerate it, and you have clearly discovered a nutritional approach that has dramatically improved your health!

  • silentwave

    I’m confused by Dr. Fung’ explanation on why Asian eating white rice was low in type 2 diabetes until Asian population started consuming sucrose and high fructose corn syrup. As he states in the book, carbohydrates are composed of sugars, single and two sugars are simple carb. Hundreds or even thousands of sugars are complex carb. White rice as far as I know is simple carbs. As he explains how sugars cause fatty liver and insulin resistance, at the end, he said that explains the paradox why rice eating Chinese were low in type 2 diabetes.

    “This explains the apparent paradox of the Asian rice eater. The INTERMAP studies of the 1990s found that the Chinese were eating very high amounts of white rice, but suffered little obesity. The key was that their sucrose consumption was extremely low, which minimized the development of insulin resistance.”

    But wait… Isn’t rice just sugars? I’m confused how he can jump to that conclusion.

    Any insight would be greatly appreciated.


    • Hi Chris

      My understanding of his theory is this: white rice contains no fructose, only glucose. Grains (and any carbohydrate-containing food that isn’t sweet) have no fructose so they break down into glucose. White flour is another example of a fructose-free refined carbohydrate. He argues that it is fructose that causes insulin resistance and that significant quantities of fructose were not consumed by the Chinese until the consumption of sucrose began to rise. Sucrose is essentially 1/2 glucose, 1/2 fructose. In my fructose science series I couldn’t find any good evidence for the theory that fructose is more likely to cause insulin resistance than glucose is, except at abnormally high dosages of pure fructose (which doesn’t exist in nature). So until there is better evidence available, I am not convinced of the fructose-insulin resistance hypothesis. It’s possible, it just hasn’t been proved yet as far as I can tell.

    • sabelmouse

      that whole ”all carbs are just sugar” thing is nonsense. the sugar industry actually came up with that to exonerate sugar.

  • Laura James

    As one of those people who can’t lose significant weight despite trying many different diets I read this review with interest and some skepticism. The only times I ever lost more than 10 lbs was on Low carb Atkins in the 80’s and the Whole 30 elimination diet plus lower carb Paleo (400 grams carbs or less per day)

    I do believe that hormone imbalance is a likely culprit (I have tested both estrogen dominant and had dysregulated cortisol results showing low cortisol) Through various means I have ameliorated both these but still cannot lose weight easily. Not to mention that IBS possibly due to histamine intolerance makes many of these diets give me horrible symptoms that makes being overweight better than following the diet.

    I’ll take this book out of library to see what he has to say. Hopefully his protocols aren’t to eat tons of food that is high histamine. The good news is I have never really tried fasting except for skipping breakfast regularly. Maybe that will be the key. Who knows?

    • sabelmouse

      remember that fat doesn’t automatically = unhealthy and vice versa.
      the greatest damage i’ve done to my health was starving myself.

      • Laura James

        So True:)

      • silentwave

        To be fair, fasting is not the same as starving.

        • sabelmouse

          where is the line? not there when you have an eating disorder. i didn’t plan to starve myself.
          my point was that , contrary to common belief, thin doesn’t = healthy and vice versa, and that trying to lose weight might not be needed for health and that it can be damaging.

          • silentwave

            I’m not a “authority” or “expert” in fasting, but I think we only need common sense and listen to our body. To me, I prepare my fasting by gorging for a big meal the night before. I stopped eating when my body tells me that I’m full. Then, I don’t eat when my body is telling me to I don’t need to eat. Sometimes, I want to eat just because I’m used to snacking, not because I need to eat. That’s how I draw the line. Listen to your body and be honest about it. I know that I’d have a big meal later when I’m done with my fast. Starving is involuntary and it’s not under your control. I don’t think that anyone who has access to the internet is in danger of starving. 🙂

            I hear your point. What I take away from the book is not that being thin is healthy. What I take away is the knowledge of hormonal effect on our body, especially insulin. I’m thin but I don’t think I’m healthy enough. I was over-weight and felt terrible too. I agree that my waist size is not everything. That said, diet has the biggest effect on my well being although it’s not the only factor.

          • sabelmouse

            in 44 years of having had an eating disorder i have had to learn to listen to my body.

          • So important, this discussion about fasting, the risks of focus on body weight, and eating disorders. Eating disorders are very complex and factors contributing to them can vary from person to person. Stabilizing insulin and blood sugar levels is very healthy for the body, regardless of how much a person weighs, but doing it through fasting can be a slippery slope for people with eating disorders, and is naturally very dangerous for people with anorexia. There is no one approach that is right for everyone, of course, but Dr. Fung’s protocol should not be used by people who are underweight and may not be emotionally or physically safe for people with certain kinds of eating disorders. However, one could say this about just about any kind of diet plan, as dieting of any kind can trigger eating disorder behavior in susceptible individuals.

            What I will say, though, is that in my clinical experience as a psychiatrist, normal weight and overweight people with binge eating disorder or bulimia tend to respond beautifully to diets that stabilize blood sugar and insulin levels–from low glycemic, to low carb to ketogenic diets–any diet that takes people off of that hormonal roller coaster quiets down cravings and significantly reduces binge behaviors.

            I do wonder whether fasting (as compared to ketogenic and other lower insulin diets) is that intermittent fasting may create a sort of roller coaster of its own, due to its cyclical nature, but this question is not directly addressed in the book.

    • Hi Laura

      Dr. Fung’s protocol doesn’t specifically hold people to high or low histamine foods, so it can be modified to suit your sensitivities. I haven’t tried his protocol myself, as I am happy with a daily ketogenic diet, so I can’t comment on how it compares for me to other approaches I’ve tried over the years.

      As for non-fasting approaches, the degree of insulin resistance seems to be the most important factor in determining which dietary strategy will be the most successful. Depending on how insulin resistant someone is (it tends to worsen over the years on standard diets), a low glycemic index diet may work for those with mild insulin resistance, a low carb diet (less than 30 g/day) may work for those with moderate insulin resistance, and those with severe insulin resistance may need to turn to ketogenic diets (which moderate protein as well, because excess protein can raise insulin and blood sugar levels in some of us, and turn off fat burning).

      • Laura James

        Thank you for your response Dr Ede. At my age I’m not actively trying to lose weight and with a BMI of 26/27 I’m not too overweight. I just want to get the IBS thing under control and watching my histamine consumption seems the healthiest way to lose weight too. I tend to eat more fresh vegetables/proteins and less processed or preserved foods, whenever I sense that histamines are getting too high in my system. This creates a moderate calorie deficit that usually solves both the histamine reaction/IBS and lose a few pounds too. If I ever want to seriously resolve weight issues I may look at an intermittent fasting diet. The only warning I would give is to make sure of your adrenal status before stressing them with fasting. That potentially is a problem for some with adrenal stress.

    • Laura, can I just say I was exactky the same as you – the lack of being able to lose weight, even on Atkins, and I have IBS. I recently embarked on Dr Michael Mosley’s 8 Week Blood Sugar Diet and have finally found a diet that works and my IBS symptoms are greatly improved. I highly recommend you take a look at it. It seems extreme but it isn’t as hard as it may look. I am on week 6, my hunger and food cravings are gond and I’ve lost 18lbs. I haven’t lost this much weight on any diet in 15 years of trying.

  • silentwave

    I’ve just finished the book. My general impression is that it’s worth the investment in time to read it with the caveat that you need to take it with a grain of salt on a lot of the suggestions. My main concern is Dr. Fung’s tendency to simplify everything through measure of insulin level and insulin resistance. On the other hand, he’s a big proponent of not looking at obesity through a single factor. He mentioned in the book many times emphasizing that obesity is a multifactorial problem but at times he did sound contradicting when he focuses so much on insulin and passionately believe that’s the root cause of obesity.

    For example, he recommends steel cut oat because it’s high in fiber and fiber can lower the insulin level, but at the same time, he also recognizes that grain is not good for you. This is just one example out of many that seems contradicting. So, it’d be hard to follow.

    • Soon to be ex rbc client

      Well lots of the factors you can’t change like your genetic predispositions.

  • Hello, John

    Great question. I looked into this this morning and found an excellent review article on the topic. What I learned is that yes, dioxins are highest in animal foods because they accumulate in fatty tissues and they originate from industrial waste sources that can wind up in animal feed:

    ” Food of animal origin is a predominant source of human exposure to dioxins and PCBs…food contamination is directly related to feed contamination…” Malisch R and Kotz A Sci Total Environ. 2014 Sep 1;491-492:2-10.

    My best advice about this would be to do your best to purchase naturally-raised animal foods when possible (pastured meats, grass-fed dairy, wild fish, etc) to limit exposure to animals fed with chemicals.

  • Tante Leonie

    I am taking amitriptyline 75 mg/day for migraine prophylaxis and I am having a lot of trouble keeping my weight down. This has never been a problem for me in the past, but
    it seems that I gain weight, no matter how little I eat.

    My understanding is that amitriptyline causes leptin resistance. I am trying to taper off the drug, but it is a long process.

    Would intermittent fasting have a positive effect, or do I just have to wait to get off of the amitriptyline?

    Thanks in advance for any words of wisdom.

    • Hello, Tante Leonie

      Excellent question. Yes, Amitriptyline can definitely cause weight gain, and there is some evidence that Amitriptyline causes leptin resistance. It can be very difficult to lose weight through diet when taking a medicine like Amitriptyline, but lowering your carbohydrate intake can sometimes help. I don’t know what dietary approaches you have already tried, so I don’t know if intermittent fasting is your only remaining dietary option.

      I also don’t know what other medications you have tried for your migraines, as there are a variety of alternatives available that don’t cause weight gain, so you may want to discuss this question with your primary care provider or neurologist.

      Migraines are strongly linked to food sensitivities, so another possibility, if you haven’t yet explored it, is that you might be able to identify your headache culprit using elimination diet experiments. Some common triggers for migraine include histamine and other biogenic amines in aged/fermented foods and beverages:, dairy products, gluten, nightshades: , food additives, alcohol, and high-sugar diets. I used to have migraines myself and was eventually able to figure out what to remove from my diet in order to prevent them.

      I hope this helps and feel free to keep us posted about your progress!

      • Tante Leonie

        Many thanks, Dr. Ede for your reply.

        I generally eat a lower carbohydrate/moderate fat diet and am planning to give keto a serious trial, along with trying IF.

        I found that my migraines responded well to Dr. Buchholz’s “Heal Your Headache” program [I went from ~15 bad migraines a month to 4]. I am not as strict as I should be with this, but now I have motivation to tighten up on this program as I really want off of the amitriptyline. I am worried that it will push me into a pre-diabetic or diabetic state.

        As to other migraine meds: I’ve tried literally everything but calcium channel blockers. If keto and a stricter adherence to Dr. Buchholz’s method don’t help, I will give those a try.

        Again, many thanks for your reply; I really appreciate it!

  • Hi John

    All I was able to find in the scientific literature is that African yams do contain thiocyanate. It is unclear whether African yams are any different from yams available in other countries. I think part of the confusion here lies in the fact that the terms sweet potato and yam are often used interchangeably.

  • Rosemary

    Thank you for this book recommendation. Dr. Fung is brilliant to synergize a wealth of information and long confusion and conflict around weight. My experience tells me he’s right. As a former athlete and now active crossfitter, I’ve been following a rigorous program since last September – logging all calories in and out, with a trainer monitoring, sleeping 7.5 hours of mostly uninterrupted sleep (always been a good sleeper) and had multiple tests done to show that I burn 1679 calories without exercise each day. After 6 months, I burned enough to have lost about 32 pounds – I lost 2 pounds. I have been slow to lose weight, even as a competitive athlete, my whole life. Now as I get older, it is becoming not only disappointing but downright maddening as I have tried everything with limited or no result. Diabetes runs in my family, and I believe that, now in my 50s, I have become insulin resistent to the point that no program results in weight loss. Reading The Obesity Code is the first time anything has made sense for me. I am going to pursue his program this week, varying the fasting periods, for 30 days. After having followed many other programs over the decades, including a personalized assessment with Dr. D’Adamo (Eat Right for Your Type), I think the timing component to “drain” the insulin combined with the right nutrition makes complete sense. Thanks for your review!

    • Hi Rosemary,

      Yes, you are living proof that the calorie theory of weight loss is wrong! Good luck with your new program and feel free to keep us posted about your progress if you like.

  • bufny1

    I struggled with my weight all my life and would lose weight on diets and subsequently gain back the weight I lost and gain even more–I was always told about how you had to exercise and keep insulin levels “steady” by eating every 3 hours. Frustrated by all this advice from so called “experts” I was incredibly discouraged until one day I read a newspaper article where Dr. Fung was interviewed about the intermittent fasting method and how it worked—for the first time someone explained why I could never lose weight sustainably–so I gave his “intermittent” fasting a try–sure at first it was difficult but Dr. Fung even discussed this aspect of the diet which helped me through the first few weeks–within 4 months I lost 42 pounds and I’ve kept it off for the last 12 months–my co-workers were so amazed they kept asking me what I was doing-I now just eat one meal a day (a very sensible evening dinner) and occassionally on a weekend I will eat an extra meal (going out with family/friends/special occassion etc) but I know I can just go back to the fasting routine without any problems. I can’t believe how much misinformation the public is fed–such as you will lose muscle mass if you fast (again Dr. Fung explained this is not the case)-how natural sweetners like stevia (which its backers claim contain “0” calories) in fact raise blood insulin levels higher than table sugar does and hence make you gain weight etc etc. You can be sure the diet industry (including Weight Watchers, Jenny Craig, Dr. Oz etc etc) will be hypercritical of “fasting” because it threatens their billion $$ industry

    • Well said, bufny1, and what a fantastic testimony to Dr. Fung’s recommendations!

    • Christine Gayfer

      I also would give the book a high-rating. I did want to point out that, as a stevia user, I was concerned about the research Dr. Fung pointed to that showed stevia raised insulin levels, despite its being low-glycemic. I am completely open to being wrong and to giving up stevia if it is not good. However, when I looked up the original research he pointed to, I found that it said the exact opposite of what he said it did. The study, published in Appetite 2010, demonstrated that insulin levels dropped with stevia only (not aspartame or sucrose) and the researchers suggested that stevia may actually be helpful to those with insulin-resistance. I have no idea why Dr. Fung reported the opposite in his book, but it is not difficult to look up the study for oneself. I only finished reading the book and looking it up today, so I plan to contact him to ask about it.

  • humblefoods

    I really enjoyed this book, the one thing I find myself lacking in the end of it is the big conclusion. If we have a set “thermostat” for weight, which I do believe, can this actually be changed with fasting? If you loose weight with this approach, will it stick? Will lowering insulin sensitivity and hence circling insulin levels over a longer time actually reset that? That is an intriguing question. I Haven’t been able to find any studies trying to answer that question as of yet, time will tell I guess. 🙂

    • Great question–wish I knew the answer!

    • Michael Wallace Ellwood

      I thought that Gary Taubes had pretty much demolished the “set-point” theory in his book “Good Calories, Bad Calories”. (I know Taubes isn’t a researcher, but he wrote copiously about all the research related to weight-loss). So I was a little surprised to read Dr Fung writing about it as though it were a fact. I’m not at all convinced there is any such thing. It might seem like a useful “model” of what’s going on, but models aren’t reality, and in this case, I don’t think it is necessary or useful. Pretty much everything can be explained (as indeed Dr Fung does so) in terms of insulin resistance and all that follows from it. There is no need to talk about thermostats. This is the main failing that I find in an otherwise excellent book.

      Well, another problem is that he seems to have accepted wholesale what Robert Lustig says about fructose. There are greater authorities on the subject (e.g. Feinman) who robustly dispute Dr Lustig’s take on fructose.

  • John S

    Great admirer of Dr. Fung. Fasting is not the same as starving. Fasting is truly amazing and the health benefits are dramatic. Fasting and MTOR regulation is starting to be better understood. The easiest way is the 8/16 method.

    Would suggest that you reduce carbs, obviously. But use all the bio-hack you can vis:

    1. Before each meal take a tablespoon or two of apple cider vinegar
    2. Before each meal take a tablespoon of coconut oil
    3. Before each meal take a teaspoon or so of psyllium

    Thus greatly reducing your insulin spike at meal time. There is also many benefits to the above… see Pubmed.

    I am 51, 6′, 165# and feel amazing. Doing IF only for 3 months.

  • Kell Brigan

    Long story short, I’ll believe it when the NIH calls the international press conference. Meanwhile… this is just another low carb diet with no 4-year data to back it up.

    • tkent26

      Which diet plan has a 4-year long clinical trial behind it?

  • Sean Raymond

    The problem with the entire premise of this book about lowering insulin levels to evoke fat loss does not reflect what has been found in metabolic ward studies. These have clearly demonstrated that whilst lower CHO intake indeed does lower insulin levels (as would be expected) this hasn’t been shown to translate into increased fat loss. We must also bear in mind that the reduction in carbohydrate needs to be balanced by the fact that in many cases, these diets involve an increase in protein which will somewhat dampen the insulin reduction because protein has insuliaemic effects.

    I am interested by the metabolic effects of a ketogenic diet, especially for fat loss, & I am aware that most of these studies tend to be short so the full effects of ketogensis may not yet have been fully explored, but this seems to be an exciting theory rather than a fact. Higher protein intakes may be more satiating & more thermogenic thereby translating to a metabolic advantage when compared to iso-caloric high carbohydrate diets but the insulin orchestrated mechanisms purported to instigate weight loss in low CHO/Ketogenic diets do not seem to be accurate.

    I realise that many low CHO diets do NOT involve an increase in protein to make up for the energy deficit caused by CHO removal but rather, consume an increase in fat consumed – if this happens then the metabolic advantage of increased protein intake as just discussed may not be seen.

    Therefore, If anyone can point to well controlled studies showing low CHO moderate protein diets DOES produce elevated fat loss I am interested to see them (note – I didn’t say weight loss – Low CHO will cause greater weight loss in the beginning stages due to increased water loss).

    The insulin hypothesis is a very testable one – so far the evidence hasn’t supported it.

    • tkent26

      Studying macronutrients while controlling for calories (metabolic ward studies) is like studying smoking while controlling for lung cancer. Appetite and subsequent “calories in” changes as an _effect_ of macronutrient composition.

      • Sean Raymond

        I certainly do agree – macronutrient manipulation may have knock on effects in terms of caloric intake – consuming a larger amount of protein may cause weight loss not only by virtue of its energetically costly metabolism but also by causing a concomitant reduction in oral intake due to increased satiety. But Similarly, a direct replacement of carbohydrate calories with fat calories will likely not see energy intake compensated for by satiety therefore leading to increased calorie intake . .

        What I just typed is simplistic of course but the point I was originally making from a metabolic point of view still more than stands. Reducing circulating insulin due to low CHO or ketogenic diets does not mean we see more fat loss – I was looking at the proposed mechanism put forward by those espousing insulins causal role in obesity and drawing attention to its obvious flaws.

        Insulin does not make people fat – it comes down to the energy status of the cell. Increased lipolysis due to reduced insulin does not = fat oxidation. All you have done is liberate NEFA from adipose tissue which, if not needed for fuel will circulate (with deleterious potential) and be re-esterified back to TAG and re-stored.

        • tkent26

          Satiety. Something(s) about the low(er) carb diet and the lowered insulin state improves or re-regulates satiety. Those circulating fats are more likely to be used for fuel, and with increased satiety, are less likely to be replaced with more food. (At least during a weight loss phase.)

          Metabolic ward studies are always equal-calorie treatments, which is useful to isolate variables but is also a decision to ignore the roles of hunger and satiety.

          • Sean Raymond

            These types of metabolic ward studies show us that it basically comes down to energy in v energy out for weight loss – but of course, this is only part of the story. We need to look at what is driving hunger as well as look to effective strategies to mitigate the cause. And you are right – these studies do not consider all the parameters of a real world diet.

            Promoting satiety whilst in a calorie deficit is one very effective approach to weight loss – but it is not easy. Low CHO may indeed be more satiating than a standard lowered calorie diet meaning less calories are consumed – so that may explain the claimed ‘edge’ it has over CRD. But if so – how?
            Higher protein could explain it but these diets does not necessarily mean it is a high protein diets whilst fat v CHO are at best equal in terms of satiety with CHO more likely to be more filling gramme for gramme. So a complicated picture emerges
            It may be the texture of a low CHO diet, which has a role in satiety, that could explain its satiety effect – I do not know nor do I know if these diets are more filling – but I acknowledge many say that it is..

            I know that it is not manipulation of the insulin response though.

        • ableright

          Coming from someone that has lost 50+ pounds and kept MOST of it off for 2 years, I think that indeed weight DOES have a lot to do with hormones, but I think it has more to do with Leptin and extremely complex signaling than insulin though I think the two hormones are related.

          Perhaps Sean (and other reading this) have heard of Stephan Guyenet? He’s and PHD Obesity researcher that wrote the extremely underrated book called “The Hungry Brain”. Basically, he purposes that obesity has been caused by Leptin Resistance which is caused by increased food palatability in vulnerable people.

          This actually makes very good sense to me, but it’s difficult to measure palatablity completely in a scientific manor. That said, he does present a lot of science behind what he says, and from personal experience I do tend to think he’s right.

          Basically there was a study done I believe back in the 60s where obese patients were fed a nutritionally complete but bland liquid diet ad libitum. The obese patients lost a ton of weight without complaining about hunger while the skinny patients lost no weight.

          This comes down to vulnerability again. I’ve known people like my cousin who has unhealthy highly palatable snacks around the house constantly. He eats small amounts and he is FULL. He’s done, and doesn’t want anymore food. People like this are highly leptin responsive. People that are more susceptible to becoming obese will lose their ability to hear leptin by eating palatable foods over long periods of time.

          Indeed, it’s very hard to overeat on a low reward diet. Typically when I’m focusing on a low reward diet, I’m eating boiled potatoes (high in carbs but with nothing added), veggies like Broccoli, and maybe a lean protein like Chicken Breast with nothing added. Salt, sugar, and fat, especially when combined with potent flavorings seen in snack foods are highly palatable in comparison. These are the “obesity triggering” food in susceptible people.

  • Harlan Sanford

    I have never added before, however for those with IBS issues, is it possible that they are having issues with wheat? There is a good documentary “What’s up with Wheat” on Netflix which may have some insight.