Addendum to Do all Diets Fail?

posted in: Aetiology of Obesity | 22

From several comments to the previous blog post “Do all Diets Fail?”, it seems that some have interpreted this to mean that I do not support any particular diet.  This is despite the fact that I have spent over a year and 60+ blog posts, and 8 hours of YouTube lectures explaining why diets that reduce insulin (particularly a Low Carb, High Fat diet) are an integral part of a weight reducing strategy.  Also despite the fact that I use LCHF in the IDM clinic on literally hundreds of patients with type 2 diabetes.

However, my point is this.  Obesity is a multi-factorial disease, as I previously wrote about.  This means, that there must be multiple targets in the pathway to obesity.  A LCHF diet, for some people will be sufficient for weight loss.  Many do extremely well.  But we cannot ignore those for whom LCHF is not enough.

Let’s take an analogy of heart disease.  Smoking, high blood pressure and family history all contribute to heart disease.  So, simply stopping smoking is important but not the only strategy to use.  We must also treat high blood pressure.  This does not, in any way, mean that stopping smoking is incorrect.  It is only incomplete.

In the same way, obesity has many facets, one of which is the diet.  Treating only the diet is enough for some, but not enough for others.  We cannot pretend that a LCHF will make 100% of people lean again.  Let’s take a thought experiment, as one of my heroes Gary Taubes is fond of doing.

Suppose, I give you prednisone, the synthetic form of cortisol.  It causes obesity.  As you get fatter and fatter, I, as your physician advise you to go on a LCHF diet.  Will it work?  Of course not.  Your diet was not the problem.  Your problem was the excess cortisol I prescribed to you.  The answer, of course is simple.  Reduce the cortisol.  You must treat the underlying cause of the obesity.  You must understand the aetiology of obesity.  Diet, in this case, is not enough.NewHOT12

In the same way, suppose your problem with obesity is the time dependent development of insulin resistance over two decades.  That insulin resistance is the major pathway by which your insulin stays elevated.  Now, I tell you to watch your diet.  Will it work?  Not likely.  You have addressed the insulinogenic diet, but not the insulin resistance.  Sure, changing you diet will lead to a lowered insulin resistance in 5 years, but that’s not good enough.  (If it took 20 years to develop, doing the reverse will similarly require that amount of time).

Suppose your problem with obesity is due to excessive cortisol due to stress and sleep deprivation.  Or chronic pain from fibromyalgia.  Will a prudent diet help?  A little bit.  A good diet is not going to reduce your cortisol.  If cortisol is the main pathway, that is what needs to be addressed.  I have, in fact, patients in the Intensive Dietary Management Program who I cannot help because their problem is caused by, say anti-psychotic medication that stimulates insulin.  Or fibromyalgia that stimulates cortisol.  Unless I can deal with their underlying cause of obesity, I cannot treat it.  But I certainly can understand it.

So, with regards to diet, refined carbohydrates stimulate insulin the most, and dietary fat the least.  So the most logical dietary treatment is Low Carb, High Fat.  Yes, I am still a firm believer in that.  But sometimes, we need to move past that.

22 Responses

  1. Sergio Castorena

    Doctor Fung,
    Excellent post, I guess that Obesity is more than just the mantra “eat less and exercise more”. We must in some cases address the correct root cause and not only a correct diet is the option.
    Speaking of hormonal obesity, what do you think of Probiotics as a way to reduce the metainflamation that can be generated by a disbiosis leading to endotoxemia and thus Obesity?

  2. Moriarty

    IGNORANCE of the Biochemistry is the reason why most dieters will put back on the weight they have lost. If they fully understood the biochemistry at play, they would keep the weight off, simple as that. The only reason they will put that weight back on is ignorance. I know this for a fact because I was ignorant.
    Twice in the past I have lost a lot of weight through calorie restriction and willpower only to put it all back on and then some.
    I had no idea what Insulin was or what it did despite having a brother who developed type 1 diabetes age 16. I had no idea what Insulin was, despite being so close to it, watching my brother inject himself with Insulin every day, I thought it was some man made drug to fix whatever was wrong with him. Complete and utter ignorance.

    7 months ago obese, weighing 110kg I watched the movie “Fathead” which kickstarted a journey of biochemical knowledge accumulation.
    I have lost 22kg eating LCHF and because of the knowledge I have accumulated around Carbohydrates, Insulin, Type 2 Diabetes, Cortisol, Fasting, Fats, Cholesterol, Alzheimers, Glucose & Fructose I know I will never put that weight back on and will lose a further 9 kilo to reach my goal.
    It’s clear to me that the knowledge of the biochemistry, Insulin in particular and what it does, is essential for sustained weight loss. Thank you Dr Fung for contributing to my knowledge, the effect of vinegar on Insulin was new to me. The more I learn of the adverse effects of Carbohydrates on the human body, the more I think Carbohydrates are, if not the root of all evil, the root of most that ails us. LCHF is a whole lot more than just losing weight.

    • Rebecca Latham


      Even people who are informed of the Biochemistry can put the weight back on. It is not as simple as you think it is. I think the whole point of this post and others is that, for some, eating the right things is only a temporary “fix”, and the weight will be regained because there were other factors at play that are not being addressed.

      By the way, I am a “Fat Head”, too, and appreciate the movie and the man and all I have learned from them. But even though I have been diligently low carb for six years, the weight always comes back. And goes away again. And comes back again.

      I am so happy for you that you are one of the ones that diet alone helped! Almost every low-carber I know has not been that fortunate and continues to struggle with weight gain. I am hoping I will learn enough here about the other things that need to fall into place so that I can have lasting results.



  3. ” (If it took 20 years to develop, doing the reverse will similarly require that amount of time).”

    This says there is no hope for me, then? I am a 70-year-old female and have been eating LC since 1972. Genetically, diabetes was on my horizon and I’ve managed so far to keep it away. I only learned about your protocol in February 2015 and following it has allowed me to lose weight for the first time in 6 years. I don’t know if I can go on fasting for the next 40 years.

    I take only one pharmaceutical, which is HRT, my FBG is usually below 100. Since last May I’ve walked at least 3 miles every day.

    In your opinion, what is a post-menopausal woman to do?

    Thank you for your research and for sharing it. I had almost given up.

    • Absolutely not. LCHF is a great start but not always sufficient. Intermittent fasting a good adjunctive measure.

  4. Geoff Smith

    You are saying that it will take as long to undo the insulin resistance as it took to create it “If it took 20 years to develop, doing the reverse will similarly require that amount of time”
    If so then Bariatric surgery would not reverse diabetes as quickly as it does for some many obese patience…. yet it does.

    • No – bariatric surgery, and fasting is much more drastic than the diet that led to insulin resistance. Therefore, it will give much, much faster results – often within 2 weeks.

      • I have spent the last 10 days reading your blogs and have had many years of “nutritonalist” thinking challenged. How I ear has changed and my practice as a Dietitian will be following. I need to be clear as to what you mean when you say “intermittent fasting”. Is it one day in 7 with no food, only bone broth?

        BTW, my bone broth is simmering on the stove until tomorrow (Vietnamese pho), so having this clarified would be very helpful.

        Thanks very much,


        • I will address this more fully in the upcoming series. Short answer is that you can do as much or as little as you like.

  5. Dr.Garry Lee

    There is something to avoid, Jason, and that’s the blanket statement “all diets fail”. I’ve considerable experience of this, being 65 is one week and having overweight and type 2 dm on my father’s side (grandmother and uncle) though my dad who was always heavy lived till 96 and never became diabetic, or if he did, his geriatrician did not diagnose it. I first became fat at about 24 and since then I’ve had a struggle with my weight. I’ve never been obese and my worst BMI was 28.5, despite more or less lifetime exercise as an adult, but I found it very hard to get thin. What of course made it so difficult was the proscription of fat etc by the idiots that be. When I was about 27 I starved myself and lost 42lb and put every ounce back on again. I never lost that kind of weight again until recently, but regularly starved some weight off only to rapidly put it back on. Nearly two years ago I gave up all sugary things like desserts, but continued with wholegrain starches (had always eaten them and lots of fruit). I lost 20lb in 20 weeks but was hungry. After more than a year it began to creep on, and having come upon Prof Noakes stuff etc., I went LCHF and in five months lost 42lb without hunger and I’ve kept it off without hunger by sticking rigidly to my 50g carbs per day. I’ve had it off 11 months. I know that people fail on this, but your diagnosis of why they fail, I contend, is in most cases wrong. Most of them fail because they fall off the lowcarb wagon. I exercise a lot, like at least 100 miles per week of cycling and 15 m walking but on a recent holiday which was completely sedentary and involved no exercise for 18 days, I lost two pounds. It’s very important for people to know that they must make a lifelong decision and that if they stick to it, they will very likely succeed and if they don’t they will surely fail. For a young doctor like you to poo hoo their chances of success is NOT a good idea. The real problem with the low carb diet is that the vast majority of people for whom it would be ideal, will never try it. Psychology is very important in encouraging them in that direction. So, think positive and talk positive! I love your lectures. They’re nearly as clear as my own used to be!

    • You are right, of course. Blanket statements cause a bit of upset. I actually don’t mean to poo hoo anybodies chances of success – only to show that there are different ways to success. From a practical standpoint, I view a diet that fails due to non compliance the same as a diet that simply doesn’t work. As a physician, to me, the end result is the same – weight regain. What I need is a diet that works AND people can follow. That is our challenge. One that I mean to answer in the upcoming posts.

  6. I am a Registered Dietitian in private practice and a friend of mine, a physician, shared the link to this blog with me several weeks ago. Everything both of us have believed to be true is being positively challenged and I am needing to rethink what best clinical practice is have used the Diabetic Exchanges for years rather than Canada’s Food Guide, but am now challenged to rethink the “3 meals, 3 snack” paradigm.

    Aiming for 20g of carbs per day over 3 meals, no snacks and a 12 hour period of fasting from the evening meal until the morning meal is understood, taking raw apple cider vinegar (2 tbsp before any carb containing meals)… but what about protein and fat, and their distribution? ie how many grams of protein per day? Which types of protein have the lower insulin response? Tuna and chicken are on the Insulin Index, but what about fish? Beef? Egg? Cheese has 15g of carbs per ounce, so that is not going to be a main source. Can you elaborate?

    How many grams of fat per day (any particular distribution of mono-, polyunsaturated, saturated fats?) What about coconut oil?

    I get that fibre is a good antidote to carbs, but if carbs are kept as close to 20g / day, is adding insoluble fiber / soluble fiber of any benefit? If so, how many grams of each per day?

    And with regard to intermittent fasting, I didn’t catch how many days a week this is recommended? Also, can this safely be done by a type 2 diabetic with well managed fbg and HbA1C close to 7?

    Maybe I should have asked this first, but do you have summary literature available with this info for health care professionals and if so how can this be accessed?

    I have started applying these changes myself and want to fully understand the recommendations and basis for them. I anticipate that my clinical practice will be changing as a result of what I am processing, so having some written literature from you would be very helpful.

    You have definitely presented very good arguments to support your recommendations, but as a clinician I could really benefit by some written guidelines. Are you able to help?

    Thanks again.

    • Intermittent fasting must be done very carefully if somebody is taking diabetic medications. For this reason, all fasting schedules are personalized in our clinic. Furthermore, careful blood sugar monitoring and adjustment of meds is crucial to avoid both hyper and hypoglycaemia.

      Guidelines are difficult. For example, you cannot write a guideline such as “Give 20 units of insulin for blood sugar of XXX” as some patients will be hypoglycaemic with that dose and others will not drop their sugars at all. It is the same with fasting. I only have a rough guess as to how the body will respond. Mostly it is a matter of monitoring and adjustment.

      All our lectures are available free online. There are slides available for download for the Aetiology of Obesity series and have the references noted.

  7. This is certainly a very good discussion which I have been following both here and over at the DietDoctor’s site.
    I agree that saying “all diets fail” was a bold statement, but I believe you have supplied enough arguments to the case to support your view. The adherence part is extremely important when talking about or comparing diets. In my opinion this is one of the important aspects where LCHF really shines, because of natural control of hunger by the two most satiating food components: protein and fat and also by the right hormonal approach to satiety. So it is quite natural when the diet is recommended to be followed as a lifestyle, usually for a lifetime. However, the problem is that other diet gurus also tend to accumulate a kind of religious throng around them while putting the exact same slogan onto their flags: it’s a lifestyle change forever, you should not abandon it for a moment. I really don’t like some of the practices modern marketing employs, but still have the feeling that finding an efficient way of communicating this could enable us to distinguish from the loads of fad diets. Science would naturally be my bet, but quite unfortunately it has a tendency and history of not working with average people.

  8. what is the cure for fibromyalgia?

  9. Thanks for your reply regarding intermittent fasting for diabetics, but in my case, no medication is involved. Yes I am a Dietitian that became diabetic *after* losing 50 lbs and keeping all but 10 off. Following current “best clinical practices”, I became diabetic. Your approach makes physiological sense, and since the 3 “meals / 3 snacks” with 45% of calories as carbs got me where I am, continuing makes no sense.

    My blood glucose has been well managed by diet (and I thought exercise), but I understand now how following current Dietetic / medical recommendations has only increased my insulin resistance.

    I am applying these principles (LCHF, low fructose, high fibre, vinegar with carb containing meals, 3 meals no snacks, 12 hour overnight fast) and I want to use intermittent fasting to further lower my insulin resistance. I have a glucometer, so can monitor but since I am not taking any medication, how should this best be approached.

    Is it one day in 7 only?

    Thanks very much.

    • You should get his book Obesoty Code or else watch all the videos/ read all the blogs. Many of us in the FB group Im in fast on a regular basis but mix it up. 24hr, 36, 48 and some go much longer. But then putting in feed days of LCHF in between. The key fir all of us is testing our BS (specially a.m. fasting) to see how we are doing. Mine has been coming down the last week or so n I have been doing this since Jan. But I still have more weight to lose too. Good luck!

  10. As always, a great posting, Dr. Fung. Thanks for sharing your knowledge and experience with us. While I am not overweight or diabetic, diabetes and blood sugar issues run in my family, so I am hyper conscious of keeping myself in the best shape possible.

    I’ve been dabbling in IF for a few years, beginning with the Warrior Diet and Fast-5, but haven’t been terribly strict. The more I read your site and watch your videos, the tighter I think I should keep my diet and fasting practice.

    Kind of an off-topic question, but at least directly related to fasting. I have often wondered and have tried to research about IF and lowered risk of gastro-intestinal cancers. It would seem to me that the less frequent the digestive system as a whole is exposed to digestive enzymes (pretty potent chemicals!) the lower the risk would be. I found a couple of published studies, but it seemed inconclusive as one show a mild correlation and the other none. Maybe I didn’t look hard enough.

    Anyway, i am curious as to your thoughts on this, even just your very educated opinion. It seems very logical to me that IF would lower risk, not just due to decreased inflammation, etc, but also the less exposure to those hard digestive enzymes.

    Thanks again for a great website and for your thoughts.

    Have a great day!


  11. Thank you for your blog! There is so much BS about diet/nutrition and your blog is just luverly to read, the voice of clarity and reason. I wish my mother was around to heed your advice; she wouldn’t have died early from years of T2 complications eating her low fat carbs including snacks every 2 hours to keep her blood sugars stable (Dr’s advice of course). Hopefully with Dr’s like yourself daring to go against the standard advice and educate people I may be able to avoid following her health problems (and my children). The only problem I struggle with is IF, it’s just too difficult unless it’s a spontaneous one – I don’t do well with planned days; seems to create an anxious type of deprivation feeling. I stick to mini IF’s during day and no eating after 6pm. I wish I could do better at this though. Anyway thank you sincerely for your advice and blog.

  12. Excellent article. You are perhaps the ONLY LCHF proponent/supporter that is not an ideologue. Very refreshing.

    Here’s the problem Dr. Fung. Just as eloquently as you write about the many causes of obesity above, exemplifying the case of cortisol, there are in fact tons of other causal factors in obesity that are not even recognized yet at the moment. That will change of course in the future… but the damage done will be so great by then. I can post hundreds of links on the high association between viral syndromes and insulin resistance. Even some mainstream doctors/researchers are beginning to talk about this, like Dr. Gregor from There isn’t even a clear definition yet on what a virus is, medically. Yet just like the way CFS and Fibro has been ignored for decades, these other viral syndromes are stealthily spreading through the population and they will not go away. As a doctor and scientist who seems sincerely interested in acknowledging all of the root causes of metabolic dysfunction, I would hope that you would be more open and open minded to hearing about this from the patients who themselves know this reality far better than scientists or researchers because they ~live~ it, as well as more sympathetic to their plight.

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