Who needs to avoid Fat Bombs and BPC?

From http://mariamindbodyhealth.com/fat-bombs

Does eating extra fat via Fat Bombs and Bullet Proof Coffee make you fat? Here’s the short answer. Yes and no. If you are slender, then eating fat will not make you fat. If you are obese/ overweight then yes, eating more fat will make you fat. Let me explain. The answer, of course, has nothing to do with calories (an entirely outdated and useless concept) and has everything to do with physiology. Let’s back up a bit.

Under a ketogenic/ Low Carb High Fat diet, people are encourage to eat the large majority of calories as fat. Generally, they should eat real food, until full. Some people have taken this to mean that they should add extra fat to everything they eat – witness the popularity of ‘Fat Bombs’ – treats or foods with very high fat content or Bullet Proof Coffee – coffee with the addition of extra oil (MCT, coconut etc). There has been some people who find this slows down weight loss and others that feel it does not. What’s happening?

Insulin is the major driver of weight gain. When you gain body fat, the body responds by increasing secretion of a hormone called leptin, which tells the body to stop gaining weight. This is a negative feedback loop, designed to prevent us from becoming too fat. This is a survival mechanism because obese animals who cannot move properly will get eaten. This is also one of the reasons why people say “We are genetically programmed to eat everything in front of our face” or “We are programmed to get fat, but food was scarce before” are completely idiotic mistaken. So why doesn’t it work for us?

Insulin and leptin essentially are opposites. One tells our body to store body fat and the other tells it to stop. If we continue to eat fructose, causing insulin resistance and persistently high insulin, then we will also persistently stimulate leptin. Like all hormones, a persistently high hormone level leads to downregulation of hormonal receptors and the development of resistance. So persistently high leptin levels eventually leads to leptin resistance, which is exactly what we see in common obesity. So, lean people are leptin sensitive and obese people are leptin resistant.

Let’s now think about the physiology of eating dietary fat. Remember there are only 2 fuels for the body – you either burn sugar or burn fat. When you eat carbohydrates or excess protein, it goes to the liver, through the portal vein and stimulates insulin, which tells the body to start burning sugar, and store the rest as glycogen or fat. Dietary fat, on the other hand, does no such thing. It is absorbed in the intestines as chylomicrons, goes through the lymphatic system to the thoracic duct and directly into the systemic blood circulation (not the portal circulation of the liver). From there it goes into the fat cells to be stored. In other words, the fat does not affect the liver, and therefore does not need any help from insulin signaling and goes directly into fat stores.

So, doesn’t that mean that eating fat makes you fat? No, no at all. Let’s take the lean person (leptin sensitive) first. Remember the story of Sam Feltham’s 5000 calories/day experiment? He ate an enormous number of calories per day, and still did not gain weight (53% fat, 10% carb). As you eat lots of fat, it will get stored into fat cells, but insulin does not go up. As fat mass goes up, leptin does as well. Since the lean person is sensitive to leptin, he will stop eating in order to let that body weight go back down. If you force-feed him, as Sam did, the metabolism ramps up to burn off those extra calories.

Sam Feltham

Now, the situation for the obese, leptin resistant person. As you eat lots and lots of fat, insulin does not go up. However, that ‘fat bomb’ does indeed go directly into your fat stores. You respond by increasing leptin levels in your blood. But here’s the difference. You body don’t care. It’s resistant to the effects of leptin. So, your metabolism does not go up. Your appetite does not go down. None of the beneficial weight loss effects of eating that ‘fat bomb’ happens. And yes, you will need to eventually burn off that extra fat you’ve taken in.

The practical implication is this. If you are lean and leptin sensitive, then eating more dietary fat, like cheese, will not make you gain weight. However, if you are trying to lose weight, and have some problem with obesity/ insulin/ leptin resistance, then adding extra fat to your meals is NOT a good idea. Once again, you can see that we do not need to go back to that outdated, and useless notion of calories. Obesity is a hormonal, not a caloric imbalance.

What can you do instead? Well, eating more carbs is not a good idea. Neither is eating more protein. Nor is eating more fat. So, what is left? That’s what we call fasting.

At this point, you might worry about nutrient deficiency. That is why so many people talk about nutrient density. How can you get the maximum nutrients for the minimum calories? This is muddled thinking. Why do I care? Ask yourself this – are you worried about treating obesity or nutrient deficiency? If you choose obesity, then worry about obesity. You don’t need more nutrients, you need less. Less of everything.

If you are instead worried about nutrient deficiency, then treat the nutrient deficiency, but let’s be clear – THIS HAS NOTHING TO DO WITH THE TREATMENT OF OBESITY. If you are worried about, say, Vitamin C because you have scurvy, then by all mean, take foods dense with Vitamin C. But it will not make a bit of difference for the treatment of obesity. The issue of obesity and the issue of nutrient deficiency are completely different. Do not confuse the two. I treat obesity, not beriberi disease. So I worry about reversing hyperinsulinemia/ insulin resistance/ leptin resistance. If you are leptin resistant, then no, adding more fat does not make you lose weight. Fat bombs, for you, are not a good idea.


I think quite a few people misunderstood the point of this post, and think I suggest a low fat diet. No, I suggest eating a low carb, high fat diet until you are full when you eat. This is the point – if you have 2 choices:

A – Eat LCHF until full.

B – Eat LCHF until full, and then eat more butter, oil, BPC and fat bombs

You should choose option A. I would have thought that this is common sense, but apparently, many people choose option B thinking it better.


159 Responses

  1. Love it. You clarified a lot for me. You can’t have your “cake” and eat it too.

  2. Fantastic as always. I have a blog, Instagram and fanpage in Brazil about fast fastingworld.blogspot.com.br, I have been translated your POSTS . Thanks for everything

  3. Les Walters

    A question then. How can I tell if I’m Leptin-resistant? Over past 17 weeks or so I’ve reduced weight by 17 kgs and Serum Insulin from 18 mU/L to 12 but have plateaued at 100 kgs. On LCHF managing carbs to ~10g/day and daily fasting avg 18-20 hrs. Looking for answers.

    • I’m not sure but I doubt there is a test for something like that, as it’s all going on in your brain and how it reacts to the signal. I’d say if you can easily manage your appetite on a keto diet then you’re probably not leptin resistant. I can only speak from experience. I am pretty sure I am leptin resistant because even after months and months on a keto diet I have a large appetite although my body has plenty of fat that needs to be shed. But hey, great job with your 17kgs! I think it’s completely fine that you’ve plateaued and if you continue eating this way it’ll pick up again 🙂 Good luck!

    • Go see an endocrinologist and ask for a leptin resistant test

    • Mirror test. Walk up to a mirror. If your belly hits before your nose, leptin resistant.

      • Kenny Tucker


      • So very true! Sounds like Jack Kruse…I think he made a similar point somewhere on his blog? Similar idea is if you look in the mirror and see excess body fat, then you are leptin resistant.

    • Dr. Nikol Hopkins

      There are blood tests that measure leptin. Our medical practice usesTrue Health Diagnostics lab, but Quest and LabCorp also have the markers. Is it worth measuring? I have yet to see a patient that is overweight (and overfat) that does not have a high leptin level. So depending on your insurance and “need to know” it may not be a wise use of money

    • In his new book the guide to fasting Dr. fung says to switch it up and try a longer fast 42 hours or more to get things started again.

  4. Les Walters

    Sorry…carbs ~20g daily and consistently in ketosis (4)

  5. So if I google “what is my BMI” and plug in my stats, I’ll be able to figure out whether or not I’m “leptin-resistant”.

    Part of me is like “wow! I didn’t know it was that simple!”. The other part of me is thinking that I should wait a few years to see if the thoughts shared in a blog will bare any proof.

    • I think the role leptin plays is reasonably well understood. I don’t think there’s there’s been a lot of progress on reversing or treating the resistance through medication – there’s certainly been a lot of money spent on developing a “cure” though.

    • The problem with BMI is that it’s wrong. A 5’5″ female weighing 185 with a body fat of 30% is obese. However a 6’2″ male weighing 300 with a body fat of 5% would also be considered obese. This is because it ONLY takes into account height and weight. There’s no real science there.

      • Elias Jones

        BMI is well-known to be useless (or to be kind, misleading), when it comes to athletes with high lean muscle mass and low body fat. For example, an on-line BMI test will typically tell an elite-level powerlifter or gymnast, with less than 8% body fat, than he/she is mildly obese and should consider starting an exercise program at the local gym.

    • BMI is a poor indicator of anything- it won’t reliably tell you if you’re overweight and certainly won’t tell you if you’re insulin / leptin resistant.
      One does not need to know one’s BMI to know one is overweight!
      If you are overweight, and have been for some time, you are likely to have a degree of IR and LR. If you are obese it is almost a certainty.
      Insulin resistance can be confirmed with blood testing. Leptin resistance is deduced by physiological response: If you lose weight quite easily by fasting / eating less this bodes well; conversely if you are one of those people who restrict your food intake and still struggle to lose weight then your body is not behaving as expected, indicating something amiss with the physiology.
      You do not need to wait to find out if fasting has beneficial effects- the research has been done over decades and the evidence has been available for years.

      • Spot on, Essexgirl..so often we think that unless something has been on the front page of every newspaper and magazine, it must be a new fad. Yet much of this information has been out there for many years.

        • *should have added that even when something is emblazoned on the front of newspapers/magazines we still think of it as ‘new’ and likely just the latest fad diet.

    • Charlene

      I am not sure I follow your logic of waiting. If you are overweight you should act NOW. This science is all new too me and I worried it was unsafe/snake oil. But, nothing ventured nothing gained (or lost in this case) right?? I started LCHF and IF and lost weight; I also went to my Dr to keep careful track of my lab work. If something was wrong–the red flags would be in my lab results. In my case my lab report numbers improved so well, my Dr said the numbers don’t get much better.
      Or you can wait and risk gaining even more weight and developing health issues.

  6. How do I know if I am leptin resistant? One can not fast continuously for more than 21 days, although my maximum is 7 days so far, one has to eat, right? What a leptin resistant person should eat?

    • why can one not fast for more than 21 days?
      One can fast for as long as one chooses, or as long as one has stored fat to provide fuel.
      The longest recorded fast was 382 days, as cited in the article, and data has been published to the effect that the faster felt well, improved his weight as well as health markers, reduced his risk of disease, and maintained his weight loss afterwards.

      • Presently I am doing the 8 week Blood Sugar Diet by Dr Mosley.
        Dr Fung reviewed it last spring as one of the best and important books:
        Done in short 8 week periods will not have impact on metabolism.
        But I am hoping, and from all accounts of ‘success stories’, that my A1C will lower from 6.1 to normal range, below 5.4. When I have lost weight I have lowered my A1C’s. A most welcome benefit

        • This was in comment to Jenny concerning 800 calories per day…below

      • Fasting for long periods should be done only with your doctor I am thinking

    • Rachael

      I know many people that have fasted for 40 days, water only. 🙂

  7. So, in summary, leptin is the hormone that controls the metabolic rate (up or down) so as to maintain a steady state of stored fat? This amount of fat stored is determined by the hypothalamus which has a “set point” that it tries to maintain (homeostasis.)

    Insulin is the energy storage hormone. So, if insulin is trying to store energy as fat after the glycogen supply is filled to capacity, leptin will increase the metabolic rate to burn off the excess energy (glucose and fat) to avoid exceeding the body’s set point.

    Am I correct so far? Does this explain how the body can adjust its metabolism by up to 40% in either direction in order to maintain its BMI set point?

    Very interesting …

    • Dave, no, leptin does NOT control the metabolic rate. It is thyroid hormone that controls that. Leptin controls your appetite. So if you’re leptin sensitive, when you’ve eaten sufficient calories for your need you will no longer be hungry. If you’re leptin resistant your body won’t recognise when you’ve had enough and you will still be hungry.

      BTW, if you fast (800 calories a day) for any length of time you will stuff up your thyroid and your metabolic rate will drop. This is the body’s survival mode and disastrous if you want to lose weight.

      • Calorie Reduction (800 calories a day) = lowering metabolism.
        Fasting = Zero Calories.
        Intermittent Fasting if done correctly raises metabolism or keeps it the same.



        Caloric Reduction as Primary strategy puts you into starvation mode.
        The key to losing weight in the long term is maintaining basal metabolism, or keeping ‘Calories Out’ high.
        Failure rate of Eat Less, Move More is proven to be 99% or so. This remains the diet advice favored by most physicians and dieticians.
        Actual starvation (fasting or bariatric surgery) does not put you into starvation mode
        Ketogenic diets do not you into starvation mode

      • This is so interesting! But I’m still confused, especially regarding the thyroid as the metabolism controller.
        Recently I’ve been reading about fasting, and plan to try some 24 hour fasts.
        I’m drug induced “hyperthyroid” because I lost my thyroid to cancer three years ago. I take high dose synthroid to stop the communication between my pituitary to any remaining thyroid tissue. I’m thinking that I’m lepton resistant, because I’ve been stalled for over a year on a LCHF diet that I’ve been on for two years. I lost 38 pounds over the first 6 months,
        I’m now forming dense fat around my waist. Yes, I’m also 50, and post menopausal.
        So the thyroid controlling the metabolism, doesn’t really explain the weight gain but leptin resistance sure does.

  8. So how much fat is enough?

  9. Can leptin resistancy be reversed ? e.g. via fasting and weight loss?

    • Martin Scott

      Dr David Ludwig has looked at this extensively at Harvard. The answer is maybe. Maybe for some people sometimes. It’s unclear. The hypothalamic damage that is leptin resistance may not always heal in adults. More research needed. Do your best & hope your body responds.

  10. So, can you also increase your leptin sensitivity by fasting?

  11. Dean Gittings

    So good. Thanks for giving me something so share-worthy.

  12. This has just made me more confused. I am trying to lose weight and following LCHF diet 70% fat, 20-25 carbs, 5% protein, are you saying that the fat percentage should be lowered? If so to what? What would your macros look like with the addition of fasting? How would you combine the two i.e. LCHF/fasting?

    • @annie mac — I think your answer is in your question. 🙂

      If what you are currently doing is not working for you eat LCHF but *with* fasting as well. So you may only eat one [or two] meal a day, and that meal would be LCHF. LCHF to keep insulin low and fasting to give your body time to access stored fat.

      I have wondered for weeks how on earth I was going to get to using my fat stores if I ate so much fat 3 meals a day.

      • So on a 24 hour fast with just 1 meal , you are limited to mainly lots of green vegetables (20-25 grams of non-sugar carbs),olive oil, some nuts and maybe slight bit of meat/one egg all totaling not more than 700/800 calories?Right now I am trying to lower my blood glucose level (fasting BG is now consistently between 9/10 or 162/180 , like to lower it to 6 or 108).Approximately how long (days or weeks) will it take to achive the target?

      • Just to add – I just started the fasting & do it everyday until BG comes down.Also on medication – Metformin+Sitagliptin 500/50 twice a day.

    • I am confused now too. What does this mean for our macros? I’m trying to lose weight. 100g fat- 75g protein-25 net carb daily. Does this mean just use fat for satiety?

    • That is my question too. I’m on a keto diet, 24 hours fasting, and calorie counting for weight loss.

    • The message here is that if you are obese it is not a good idea to exagerate fat intake / binge on fat, like some people do, thinking that as “fat doesn’t make you fat”, they can eat it without limits…

    • Stephen Town

      Annie Mac, if you’re eating 25% of your diet in carbohydrates that’s high by LCHF standards and your protein is low at 5%. You won’t burn fat until you’ve used the carbs and your insulin has dropped. I don’t really count, and don’t think people should obsess, but a more typical ratio would be something like 70% fat, 15 – 20% protein and 5 – 10% carb. So, no you’re not eating too much fat, but you are still at the high end in terms of carbs/glucose. That said, most people in the US will be way higher.

      I believe Dr Fung is saying that if your system has been damaged by your diet, then your leptin (enough) switch may be damaged, so you can’t just eat as much fat as you want. A bit of common sense and restraint is required in this case.

      If insulin resistance improves with LCHF and IF, then there would seem to be good reason to believe that in time leptin sensitivity will also improve. I’m assuming it’s a matter of how much damage we’ve done before making the change.

      Best wishes.

    • Tfisher

      well lets look at this. if you are doing a ketogenic diet(20gms carbs/day) and desire to lose body fat……..where do you think you could make up the fat in your LCHF diet???? answer:on your own fat stores. i belong to a group that does nutritional ketosis……specifically for weight loss. Once you reach maintenance, this is where you may increase your fats. Weight loss still has a calorie deficit approach. You want to use the fat stores on your body for energy….if you are constantly adding a lot of fat to your foods, you will use that first. my macros for a 5’3″ female is 110g P/71g F/20g C……..basically not more than 1200 cal a day…..Please do not forget we are using our fat stores for extra needed calories throughout the day. (LESS FOOD ON YOUR PLATE=MORE FAT OFF OF YOUR BODY) for consumption. …may i suggest 2 Facebook groups Ketogenic dieters and ketogains. They are a fabulous addition to your knowledge on your journey of ketogenic and IF combined……and only use science to back their results. Literally thousands of inspiring stories of people that have lost 100+ pounds. It was there where i learned much on nutritional ketosis..it was there that someone mentioned Dr. Fung…and whyLCHF wasn’t exactly what i was looking for in my personal health journey. When you log everything you eat, you would be surprised how easy it is to get to 71g fat eating normal whole foods like avocado or beef…..and the little oils you use for cooking or on salads.

  13. I’m also confused. I’m now on a strict lchf (20-25 carbs per day) along with daily IF (usually 17-18 hours fasting and 6-7 hour eating window with 2 meals normally). But I can only do this by having coffee with coconut oil in the mornings/early afternoons. I’m not doing excessive cardio like I used to- 2 hours a day); actually I’m not even exercising yet as I’m worried about messing up a good thing. I’d gained 50 pounds the last year steadily no matter what I ate or even with excessive exercise, whole foods, lower carbs and couldn’t lose weight. I’m also perimenopausal. Since my new routine, I’ve actually FINALLY lost weight (12 pounds so far in 3 weeks) and my appetite and cravings are under control. I have over 70 pounds to lose. I’ve tried many, many things to lose weight and this is the only routine that has produced positive results. I had fasting blood work done last week, though, and both insulin and glucose levels are very high (22.6 and 116 respectively) so since I’m on the verge of developing full-on diabetes I’m terrified of not reversing this through a LCHF regime. I don’t know what else to do. Can I assume since this is working for me that somehow I’m really fat but not leptin resistant? Is there a percentage of fat that reaches the fat bombs level? I’m averaging 65-70% fat, moderate protein and very low carbs.

    • Stephen Town

      Mo, you can assume you’re doing well. Keep going, be patient and see where the blood sugar is in, say, six weeks. I think it will show a lot of progress.

    • If will be good of you enrol in dr fung program.

      As an aside, I use to have bt of 12, and metabolic syndrome. Now all my markers are ok and hv drop 24% of my weight. All in a matters of a few months.in my experience lchf is too slow. By accident I had a very bad tonsillitis, so bad swallowing my saliva was painful. Automatically, I was on a 10 day fast.in that period, my big drop to 3.2.my weight drop 5%. Later my blood test show Uric acid, normalize, cholesterol from fm 10.2 to 6.2. Blood pressure drop fm 150/110 to 100/65. Heart rate drop fm 90 to 60. Before this , I was on am extreme low carb diet. Just veggies, fish, tofu, mushroom and a little meat 3 meals a day. Progress was arduous for 3 months.

      All this happen by accident, lucky? That was when I begin to believe what dr fung is doing. Fasting is truly incredible.no more playing and with other diets and supplements .nowim on lchf with if for maintenance the past 1 year and am taking resistanvce starch occasionally for its nutrition like potassium and magnesium.btw, i am constantly in ketosis whiteout counting carbs, oil n protein composition as evidence by checking o thru ketones strip.i het knock off sometimes, just a 24hr fasting puts me back on as ketosis helps reduces inflammation a by product of being diabetic n metabolic syndome.morever fasting starts up autophagy and produces 5x more human growth hormones.most diabetic hv badly damage organs and blood vessels.

      Keep your chin up,many have done it with longer term fasting.lchf reversing diabetes testimonials report taking normally takes months .if you are worried, try fasting it is incredible.

  14. There is a typo in this. It should say, “if you are lean and NOT leptin resistant, you can eat cheese and not gain weight”.

  15. Thank you Dr. Fung! You had us worried in that interview with David Asprey, where you seemed to give tacit approval to him suggesting we should all drink Bulletproof coffees all day long (that he sells).

    • I never read anything by Asprey any longer for that, and so many other reasons…Dr. Fung has more common sense and solid information to offer than most of the others combined, imo..

  16. Hey, Dr. Fung — met you at LC USA in San Diego last summer. Here’s my deal:

    I was eating 20-50 g of carb per day, 100-120 g of protein. My HbA1c was 5.1, but I was still running fasting sugar in the pre-diabetic range, even on Metformin and Victoza. The doc told me I was really good at gluconeogenesis.

    I tried fat-fasting — 1000 calories per day, as close as I could get to 90% of ’em from fat. I lost a pound a day, was never hungry, and could do my Slow Burn weight lifting. My morning BG was normal practically overnight. After 10 days of FF, I went back to standard a standard LC diet interspersed with days of FF — and also cut my protein to about 80 g and increased my fat to compensate. (IE, instead of a whole rib eye I would eat half a rib eye with butter melted over it.)

    My fasting BG stayed golden. It seemed evidence I was doing something right. I also continued to lose weight.

    This habit was derailed when I got another cookbook contract — unless I’m specifically writing Fat Fast recipes it’s hard to maintain this pattern while developing recipes. Some of the weight came back on, but the fasting BG has stayed in the normal range with the new protein-to-fat ratio.


    • Dana,
      When I tried KETO for 6 months and stalled I upped my fat to 90% and started gaining weight. Maybe it works for some but the only thing that seems to work for me is the fasting itself.

  17. My personal N=1, testing high on insulin resistance, if my fat falls below 80% of my diet I stall and stop losing. If i increase my fat back to 80%+, I will steadily start to lose again. I also have my best glucose/ketone readings after high fat days. My loss may be slower (54 lbs in 9 months, about 40 left to lose), but I’ll take slow loss over no loss.

    I tend to stop tracking my food when I get comfortable. Then I stall. Then I start tracking again and find the only thing really changing is my fat. So my personal outcomes do not match this article.

  18. So if you’re likely leptin resistant and obese Dr Fung is saying to fast. What if fasting even for 14 hrs brings your blood sugar to an uncomfortable and even dangerous low level. What should I do then?

  19. Typo alert:

    “If you are lean and leptin resistance, then eating more dietary fat, like cheese, will not make you gain weight.”

    I presume the good doctor means “leptin sensitive” instead of “leptin resistance” [sic].

  20. Dr. Fung,

    “If you force-feed him, as Sam did, the metabolism ramps up to burn off those extra calories” would then mean that “if you reduce calories, metabolism will slow down” but that is not necessarily a good thing, if that is the case. The increase or decrease of metabolism is directly correlated with ageing. Animals with very fast metabolism live much shorter lives than animals with slower metabolism. Thus, Sam’s 5000 calories, if that increased his metabolism, it also made his life shorter…

    I think that what is true for burning carbs is not necessarily true for burning fats–but “burning” I mean metabolic processes. A 5000 calories SAD diet wastes a lot of energy in free radical creation and heat release whereas the same 5000 calories on the ketogenic diet doesn’t. Therefore the kind of metabolic process chosen matters. Furthermore, reducing calories (by say fasting) doesn’t reduce metabolic process (by nature). Imagine, just as over obese animals are easy pray, so are very thin but sluggish pray, which is what reduced metabolism would cause.

    I think the argument needs a bit more research.


    • Hi Dr Stanton,
      Wouldn’t Time and Homeostasis make the difference? Forcing 5000 calories would make most people’s lives shorter if done long term. Reducing calories by means other than fasting does slow down metabolism (otherwise there would be a “Biggest Loser” reunion show) which will almost always fail long term and then you’d be back where you started (fat and living a shorter life). If you get to a point where your fat stores are too low (less than 10% (?)) and you are not taking in enough energy, well yeah, fasting would not probably work out you.

      I think Fung’s post is easy to prove. The part in Bold:
      “However, if you are trying to lose weight, and have some problem with obesity/ insulin/ leptin resistance, then adding extra fat to your meals is NOT a good idea.”
      So, if obese and following Keto while eating extra Fat Bombs and are not getting the results you want, try fasting to see the weight say bye-beye.

    • Hi Dr Stanton,
      Wouldn’t Time and Homeostasis make the difference? Forcing 5000 calories would make most people’s lives shorter if done long term. Reducing calories by means other than fasting does slow down metabolism (otherwise there would be a “Biggest Loser” reunion show) which will almost always fail long term and then you’d be back where you started (fat and living a shorter life). If you get to a point where your fat stores are too low (less than 10% (?)) and you are not taking in enough energy, well yeah, fasting would not probably work out you.

      I think Fung’s post is easy to prove. The part in Bold:
      “However, if you are trying to lose weight, and have some problem with obesity/ insulin/ leptin resistance, then adding extra fat to your meals is NOT a good idea.”

      So, if obese and following Keto while eating extra Fat Bombs and are not getting the results you want, try fasting to see the weight say bye-bye.

  21. Since the answer is not eat more fat, not eat more carbs and not eat more protein – but just fast. It got me thinking that I can ADF (fast every other day) and eat hamburgers and ice cream every other day too. If only.

    • Martin Williams

      Hello, Steve. You may be aware of it already, but Krista Varady’s EOD partial fast protocol (5-600 calorie allowance during ‘fasting’) permits indiscriminate food choices, since her research found no difference between high- or low-fat eaters’ results for weight loss.

    • Charlene

      burgers are fine–just lose the bun

      ice cream is fine–just lose the sugars

  22. Love it. Trying to remember the last time I treated beriberi….yeah never. Love all of this info. You are amazing and brilliant and my patients have benefited so much since I started talking to them about what I have learned from The Obesity Code.

  23. I think the article basically says not to eat extra fat, as in there is no need to be eating fat bombs and BPC in addition to your meals. My day starts with breaking my 12+ hours fast with a cup of BPC. That is my breakfast and if I recall, BPC does NOT break your fast at all since there is no protein, carbs or sugar in it (correct me if I’m wrong). I then eat my normal low carb lunch with some fats, effectively breaking my fast of 16 – 18+ hours (remember I”m under impression that BPC does NOT break my fast) and then I eat my dinner at until 7:00 PM. I don’t snack in between for the simple reason that I am just not hungry. I’ve lost weight even though I am not consistently doing LCHF and do a eat what I want to eat on the weekends. Intermittent Fasting, I am consistent for the past 2 months now and love it. Sometimes I fast longer than 18+ hours and I usually end up eating only 1 meal for that day.

    • Yes, you are right, it does not break your fast. Well maybe 10% but it’s probably not a big deal.

    • Well, taking any food at all, including BPC “breaks your fast” by the strict definition, but Dr. Fung allows for it (or low insulinogenic things like bone broth) if you need it to skip meals. You’re still breaking your fast, but you are still getting most of the benefit.

    • Blazer, you are right. If we are fat, we don’t need EXTRA fat added to whatever LCHF meals we fit into our fasting schedule. The fat built into the LCHF meal/s is enough and probably more than.

      For me,I do 24/1 hr OMAD with it being basically a keto meal. I can’t eat more than a smallish serving before the intense urge to ‘not have any more’ kicks in. The sight and smell of food at that point is completely a turn-off. I do worry that the calories in my OMAD would technically put me in the calories restriction camp unintentionally. I need to work up to multi day fasts I think.

  24. “You body don’t care.” Hard to take anyone seriously whose writing/editing skills are so poor. “…completely (idiotic) mistaken.”

    • Oh please! He’s a rather busy man, posting FREE blog info to help people. Between clinic hours and hospital rounds, I can accept a typo here and there. Why don’t you criticize the content and make your own (idiotic) comment productive?

    • Stephen Town

      Marra, an editor might point out to you that using a virgule (/) between words is poor style. I’m with Pete. A busy man takes the trouble to help the public with their health and you want to nitpick. Unimpressive.

      “Your body don’t care” is non-standard but direct and perfectly understandable.

      • Charlene

        Guess you missed his tongue and cheek style.

        • Exactly! Some people have no sense of humour. I laughed out loud when I read that part. Totally intentional by Dr. Fung ?

        • That’s how I took it, too. Just a statement made incorrectly on purpose to lighten things up. My daughter texted me yesterday to ask me how something was, and I answered, “it was poifect!” She responded with an lol because she knew I was joking around.

    • My opinion is that Dr Fung has a great sense of humor and writes/talks in “slang” occasionally. He does know the difference!

    • Sue and Tony

      Marra ~ Maybe when you spend thousands of dollars on an education and countless hours of research and give it all away for free to save literally life and limb you can be critical. Until then, go play in some other sand box.

      My husband was diagnosed with T2D a year ago. A1C 11.5. Fasting BG was well of 300. Yesterday he had his blood work done. A1C 5.6. Fasting BG 101. And tats all we’s cares bout.

      Tanks Dr. Fung! 🙂

      • Well said, Sue and Tony.

        What wonderful results. With all the health problems and costs of diabetes, you’d think the Government would be rushing to talk to Dr Fung and people like you. Instead, the taxpayer keeps paying the bill to keep people sick and pharma shares healthy.

        • Thank you Stephen T. When my husband had his physical and his blood work was ordered (and we had to fight for an fasting insulin test, which came back 5.3!!!) she told him to make an appointment in two weeks to go over his labs, have a diabetic foot check, discuss having a diabetic eye exam, and to discuss possible new medications, even though… he wasn’t taking ANY at the time of his blood work. She was very confident that his labs were going to come back bad.

          When we saw his results (not surprising to us) he canceled his appointment. This is what he wrote to his doctor: “In looking at my blood work, I’m not sure another appointment is necessary at this time? Clinically I would say I have completely reversed my T2D without any medical intervention. My plan is of course to continue eating a low carb high fat diet with intermittent (short/long) fasting as this has brought my A1C from 11.5 to 5.6, my fasting BG from 323 to 102 and my fasting insulin is at 5.3 which from everything that I have read means I’m not even insulin resistant.”

          Unless you have some concerns I think I would just like to just schedule another A1C, Fasting BG and a Fasting Insulin test in 3 months. Thank you for your time.

          And her response was: “That will be fine”. Not that we expected anything else but as our physician wouldn’t you think she might be more interested in what it was that we did???? Not that we need her to gush over the results but at least a “congrats on the great blood work”….. something, right? So like Dr. Fung sadly states, “He got healthy in spite of his doctor.”

          Cheers to Dr. Fung and all his great work!!

    • Sharon A Peters

      I do not know this for a fact, but it is entirely possible that Dr. Fung is either a Mandarin-English bilingual, or that his first language was English. in which case it is not unusual to encounter infelicities in grammar … especially considering that his posts are only a part of a very busy schedule. You may be the exception, but it is quite common for things like that to slip in to items we write because the brain operates far more quickly than do the fingers when typing on a computer keyboard. Additionally, I would suggest that you focus on the message and not the messenger: editing takes time, computer grammar programs do not catch all “mistakes”, and it is notoriously treacherous to try and edit one’s own writing.

  25. Fasting is good! But when we DO eat, we need to make a choice on what to eat. A low fat, high carb diet (I know that sounds terrible to most readers of this blog… don’t hate me LOL), when coming from *whole* foods given to us by nature is EXCELLENT for both nutrition and weight loss- there’s no compromise. Maybe all the readers confused by this low-carb viewpoint (which I used to excitedly subscribe to), should consider if the confusion is a red flag. Put nature to the test and trust that the wholesome, beautiful, delicious foods that come from the earth should make up 100% of your diet (it’s not confusing at all, it’s extremely… natural. And simple.) When we add oil OR sugar to natural foods, we are opening ourselves up to negative health consequences. Oil and sugar are a wonderful and essential PART of WHOLE foods (olive oil is not an olive, vegetable oil is not a vegetable, fructose is not a fruit, etc), but when we remove them from their source and use them on their own, or add them to something, they are no longer good for us. Cut out all the *added* fat from your diet, the *added* sugar, and *processed* carbohydrates, and try to see natural, whole (carbohydrate) food sources for what they are; wonderful sources of energy, nutrition, and fiber. See if you don’t get healthier. If you need some doctors to follow, try listening to Dr. Barnard, Dr. McDougall, and other vegan doctors on YouTube… even if you know you would never be vegan, these doctors can convince you at least of the health benefits of embracing, and basing your entire diet around fruits and vegetables, and then you could make the personal decision as to how much meat/dairy should be in your diet. These doctors are just as intelligent and fun to follow as Dr. Fung. They also understand the power of fasting. 🙂

    • All of what you’re saying would be true if we ate natural foods while living in the wild. Not if you get your food from a grocery store. Your argument would indicate that you could eat unlimited bananas all the time. It’s clearly not. Dr. Fung, here, is doing a great job presenting his views and you probably shouldn’t use this forum to promote your doctors…go do it on their blog.

      • It is true even for people who shop at grocery stores. I personally believe we are supposed to get most of our calories from starch, not fruit, but fruit is a wonderful source of nutrition as well. I enjoy Dr. Fung’s blog for the science, and for comparison purposes, and others may too. There are doctors who are helping people reverse their diabetes left and right (and are successfully eliminating many other health conditions as well including obesity), and are doing it with a high carb (and high nutrition) approach. Even if Dr. Fung disagrees with their method, he can’t argue with the results, and why would he want to? It’s just something people might want to look into.

        • What you say is true in its own context.

          Personally, after revering fm metabolic syndrome in a few months using, fasting, if and low carb, I have gone on to other ways. All independent of medications.

          I try Nobel prize winner of medicine like dr Louis ignarro on nitric oxide, last year winner on autophagy, previous winner on the fact cancer cells cannot exist in an acidic environment, vitamin k2 and others.
          I find that it works better and faster.no one has a monopoly on reversing diabetics. It is all about working together in this new frontier.

          Btw, I agree with you that everything created by god is good. Only if it is natural and we do not abuse it or go to extremes by insisting there is only one way. Morever, different folks needs different strokes.

        • Sarah, the idea that fruits and vegetables are the healthiest things we can eat is not backed by science. But you can see it for yourself if you look at major nutrition databases and compare nutrients in foods. The push for 5-a-day, 7-a-day, etc. was dreamed up the by the Fruit and Vegetable producers of California at a meeting in 1991. Do the research and see it for yourself. Veggies are certainly wonderful tasting and add nice color to our meals, but they’re not the nutrition bombs we’ve been led to believe, either. Here’s a sample article you can read to get an idea of what I’m talking about.

    • George Thomas

      For people who are metabolically f*cked, eating a diet of 80% carbs is an incredibly stupid thing to do.

      • Not necessarily. A very low-fat, and low glycemic diet, even though relatively high in carbohydrates, would be a very smart thing to consider. You call it stupid, but are you sure? 🙂

        • Sarah have you ever been diabetic or insulin resistant? You reversed those conditions with a vlf 80% carb diet?

          For me personally, I tried your ideas in general most of my life eating mostly organic from my own garden. I gained 100 pounds in 30 years so you’ll have to forgive me for not buying into it anymore. Fasting and LCHF have been the only things that have kept me from diabetes. I’m definitely insulin resistant and need to reset my body.

        • Low glycemic doesnt mean low insulin. Its the insulin resistance Dr. is addressing.

      • Ill advised might be better than incredibly stupid.

    • Fruit and carbs are a disaster for diabetics and insulin resistant people. They raise insulin levels, which trigger fat storage and increase hunger. I’m guessing the majority of Dr Fung’s followers fall into those categories, so this is why your high carb, low fat recommendation isn’t being well received. Believe me, pretty much everyone I know I tried low fat high carb–all thru the 80s especially. My family tried it eating unprocessed, natural foods as well. It didn’t work for us or for the rest of the nation either. Probably a great diet for thin people though.

    • Been there, done that, lost teeth (and less weight than on keto).

  26. I just need some clarity here. I am hearing that a LCHF way of eating is not good for weight loss if you are already obese? So then should it be low carb, moderate fat and moderate protein? And what is the difference of eating too few calories and going into starvation mode and not eating any calories while fasting for extended periods and not going into starvation mode? And if I am IF and unable to eat an adequate amount of calories in the short window that I am eating in, am I then at risk of my body going into starvation mode? I just want to do this right.

    • As I was reading Dr. Fung’s post, your question is what I was thinking still would need clarification for some readers. I think his answer would be that you are ok as long as you aren’t chronically raising insulin while eating low-calorie. That is what actually causes slowed metabolism. If you are eating a satisfactory amount during your eating window, the fact that you aren’t eating outside the window won’t harm you since insulin is low.

      As for not eating LCHF, I think the key here is that ‘H’ is ‘high’ only in comparison to the carbs. It doesn’t mean you should force feed yourself fat if you aren’t hungry for it, just to reach some arbitrary calorie target.

      • “I think his answer would be that you are ok as long as you aren’t chronically raising insulin while eating low-calorie. That is what actually causes slowed metabolism. If you are eating a satisfactory amount during your eating window, the fact that you aren’t eating outside the window won’t harm you since insulin is low.”

        Thanks for this, it cleared up a question in my own mind.

    • This is not exactly a forum for keto.most of dr fung articles are about reversing diabetes, with obesity and ketosis as being secondary benefits. Look at it from this context, and a lot of things will clear up.

      If you are only after weight loss, following dr fung will be a little drastic. Keto, dr ornithology, Mediterranean , paler all works. Depends on what you want. To draw fung, weight loss is just a fringe benefit. It is the internal fats in the blood and organs like liver and pancreas that dr fung is single mindedly going after .

      • I’m not sure I agree. Obesity is a sign of metabolic syndrome. Where you find obesity you stand a good chance of finding the others, or a risk of finding them in the not too distant future.

        • Terry teh

          Gotta agree with you. But different folks have different needs and varying tolerance.most of dr fung cases are pretty serious. So some may go for ‘easier’ diet.in my experience, most of my friends just wanna lose weight and the girls just wanna weight loss and better skin complexion.

          Anyway, I was replying to chrisTine,to put things into context.

  27. I was obese a year ago this month. Started keto and enjoyed fatty fats + fasting/IF.

    I’m no longer obese.

    I guess, like everything you read online, you have to take with a grain of salt and do what works beset for You.

  28. Mary Howard

    Dr Fung states, “If you are instead worried about nutrient deficiency, then treat the nutrient deficiency, but let’s be clear – THIS HAS NOTHING TO DO WITH THE TREATMENT OF OBESITY.”. To me, this is a very odd thing to say. In the 1950’s, not many people were obese, but the reason especially women were not obese was that they chain-smoked constantly, and the smoking suppressed hunger and was a substitute for binge-eating. SUPER, GREAT, NOT OBESE!!! How wonderful! And no doctor or any researcher would say that today. I have had two good friends die of lung cancer; one woman, one man. The woman died at 54, the man at 52. No one on any sort of diet to reduce obesity would stay on that diet if it meant you would die at 52, but that was precisely what the “smoking diet” did to people! So it matters what the nutrition is, not just the obesity; if the diet helps you lose weight, but turns out will kill you before you turn 60, people will turn away from it once they realize that, and oh by the way, will sue you big time.

    • What he is saying is that obesity is a SYMPTOM of metabolic syndrome and thats what he is treating. Weightloss is a side effect of that.

    • alaric Khan

      They ate 3 meals and no snacks usually. Then their last meal tended to be early enough before bed that they had a longer fast before breaking it than we on the standard American diet would manage eating 5, 6, 7 times a day. The key being that on only 3 meals a day and mostly no snacks people in the 50s were keeping their insulin low which is why they were thinner.

  29. I would say that while leptin is an interesting hormone, whether or not you gain weight with eating high fat has much more to do with your insulin levels, which is of course the storage hormone. So high insulin plus high fat means more fat storage. People who eat very low carb diets tend to have more healthy insulin levels so they don’t over store fat, not from carbs by way of lipogenesis, not from the fat either.

    The more interesting side of this though is why these people can eat gobs of fat and all this fat does not make them more insulin resistant. So they tend to say, fat doesn’t make you insulin resistant, although we know that this makes you insulin resistant like nobody’s business, normally that is, and there’s a mountain of evidence supporting that. If we want to make rats diabetic, all we have to do in fact is give them a high fat diet, winner every time, at least with “normal chow.”

    Very low carb isn’t normal chow though and that’s the difference. So high insulin in combination with high fat causes insulin resistance, and this is very inflammatory, but if insulin levels are kept down then this isn’t going to be a problem. So you won’t gain weight or worsen insulin resistance either. A high fat diet with high insulin will make you both fatter and more insulin resistant, and this is why if you are on a higher carb diet, you do indeed get worse when you add more fat.

    • Eating fat while your insulin is high will probably help you put on more weight, but do we know that it causes insulin resistance in humans?

  30. Martin Williams

    Jimmy Moore, take note.

    Emerson wrote, “A foolish consistency is the hobgoblin of little minds.” Sometimes this blog stretches the latitude that axiom suggests.

  31. Here’s a question for you:
    I have had a lot of trouble losing weight. I finally had a consult with the great Dr. Lustig who said I have excess insulin not related to diabetes. His suggestion was low carb, but low carb made me hypoglycemic. Cutting calories and increasing exercise did nothing (even with nutritionist and personal trainer supervision and more than 1,000 cal deficit daily). She experimented with increasing my calories to 2800 cal and I didn’t gain anything either. So, I finally tried Paleo (+dairy). Still watching my macros and calories, I kept them the exact same as when I was just eating regular food (calculating net carbs to account for increased fiber). I started losing weight. I wasn’t exercising, only watching my food intake and making sure my macros and calories were exactly the same as before Paleo. If my fat went over the 30% my nutritionist recommended (I was eating 1700 calories a day with 50% carb, 20%protein) I stopped losing weight. Because of that, this article really hit home for me.
    The question: what is it about this way of eating that is so magical?

    • Claudia Wheeler

      Katie Did, can you explain what your are doing now that is helping you to lose weight? I have a lot of trouble, too. I’m confused on what you did that actuallly worked. You weren’t Paleo before? Do you eat fruit for example, as that is Paleo? You are now keeping fat to 30% and you are at 50% carbs (what kind of carbs?) and you are losing weight like that????
      Can you be super clear on what you are doing NOW and are you still losing? THANKS!!

      • I don’t eat fruit. I might try to incorporate it when I am happy with my weight. It’s basically paleo plus dairy. I eat a lot of squash and sweet potato for carbs. Lots of greens as well. No grains no added sugar.

  32. Dr. Fung, is it counter-productive to take PG-X while fasting to help curb appetite? They’re basically MCT-oil and fibre pills that are supposed to help regulate blood sugar and curb appetite. I’ve been taking them for about 6 months because I’m constantly famished without them, whether or not I’m fasting. During fasts, I drink a ton of water and rich bone broth and I occasionally eat coconut oil, but none of these help me curb my appetite for more than 10 minutes. Because of my hunger, I’ve never been able to fast longer than 3 days, although I’d love to. PG-X is the only thing that seems to help, but I worry I’m defeating the purpose of the fast. Thanks in advance.

    • Sarah, I drink coconut oil twice a day with salt and I find it does help to curb my appetite. But you must give it at least half an hour to affect your system. Ten minutes is far to short a time to know if something is working.

      Since I went LCHF, I have true control over my appetite for the first time in my life. I’ve noticed that I’ve become very carb sensitive and they fuel my appetite.

      • Sarah, I should add that I’m much less ambitious about the length of my fasts. I aim for 16 hours four or five times a week. I know some people like the challenge of going longer, but I’m really not sure that we need to go to extremes, unless there is a particular reason. Speaking personally, keeping things going long term is easy for me if I keep my goals realistic.

      • Thank you for your reply, Steve. I’ve been eating LCHF since 2011, and did notice significant improvements in the beginning. Over the last few years, however, I’ve been steadily gaining more weight and becoming hungrier more often. Wondering if it’s an insulin issue, which is why I’d like to try for a longer-term fast.

  33. I think this may address the argument about whether one needs to count calories on keto or not. Some people insist that they do, others do fine on lazy keto. It seems likely that those who do well on lazy keto are less leptin resistant than those who do not.

    I’ve found that I’d rather fast longer between meals than count the calories of each meal.

  34. Dr. Fung, I very much appreciate your posts and look forward to them every week. I also follow you on Facebook and Twitter and I regularly refer to your two books “The Obesity Code” and “The Complete Guide to Fasting” as well as your YouTube videos. I find all of this information very valuable and encouraging. I also subscribe to Dr Eenfeldt’s Diet Doctor website as well as Marty Kendall’s Optimizing Nutrition website. I have researched many other websites, videos and facebook groups and have concluded that some of them are not as accurate, informed or helpful as others.

    I am a 66 year old woman who started off last Jan 2016 at 303 lbs and Type 2 Diabetes. I am following your advice on my own. I have developed an Excel spread sheet where I track my daily weight, year to date weight loss and macros as well as morning and evening blood sugars. (I measure BS more often but I don’t record it on the spreade sheet – too much data gets confusing). I used to take both Metformin and Gliclazide and now do not take any diabetes medications. My blood sugars both fasting and after meals have been in the range of 6-7 mmol over the last 6 months without any diabetes medications.(Lower on longer fasts).

    I lost 56 lbs in the first 7 months but then plateaued for the next 6. It has been difficult and sometimes discouraging, and I have fallen off the wagon many times, but I always get back on. One of the reasons is that I have severe chronic pain almost 24 7

    I have recently started to lose weight again after a implementing a more rigorous diet than before of 40 to 50 grams of protein and no more than 20 grams of carbohydrates net of fibre, going on a 5 day fast and then continuing with 3 fasts of 36 hours 3 times per week.

    You have posted and referred to many almost miraculous success stories. Which in some respect are motivational, but in other respects are demoralizing when you cannot replicate these results yourself even after so many months of deprivation.

    My request to you is, that you devote a blog entry to exploring the fact that some people have a tougher time and lose weight more slowly than your “star students”.

    You could highlight examples of people who have had a more difficult time and lost weight more slowly, perservered and eventually succeeded. Those of us whose results come more slowly need some encouragement too.

    Thank your for all you are doing. Without your tireless work, I would not have been able to accomplish what I have thus far.

    • Thanks, Birgit. I, too, find many of the success stories demoralizing, especially since some very bad advice gets mixed in with the good. I reduced carbs & protein, which reduced my bg (I’m T2), but didn’t help that much with my weight. So often I’ve read that I don’t have to count calories & to make low carb work I must eat a lot of fat. I was even scolded on a low carb forum for saying rabbit was good; it’s a lean meat so “forbidden.” However, I’ve come to the conclusion that to see results, I’m going to have to be on a low calorie, low fat diet, as well as low carb.

      • Claudia Wheeler

        Why would you go low fat, Bonnie? I don’t think Dr. FUng is saying that at all. He’s just saying to add a lot of extra fat. I think that’s what he means.

        • Claudia Wheeler

          I mean he’s saying NOT to add a lot of extra fat either, but def not a low fat way of eating.

      • Stephen T

        A low fat, low calorie diet is one that leaves people hungry and has failed consistently for 40 years. Low carb with a higher fat content should mean you aren’t hungry and allows you to fast to some extent. The low fat diet is a predictable failure. If your blood glucose has improved on low carb, that’s important. You might have to play around with the proportions, but some combination of low carb and fasting is the way to go. As I’ve said elsewhere, I don’t think fasting has to be extreme to help. I usually do 16 hours and that will also help lower your insulin and allow you to get into fat burning mode when all the carbs are used. Best wishes.

        • I should have said lower fat, as I am still eating some. But if the only way to lose weight is to lower calories, the fat is where they are. I eat fewer than 20g carbs & fast most days from my late lunch to breakfast. But recently (before cutting some of the fat) I’ve been very hungry in the evening & went from an occasional lc snack to almost a meal. That doesn’t help my bg or weight at all. I hate being so hungry, but I guess I’m going to have to live with it until I get my weight down.

  35. charles grashow


    Dr Fung

    HAve you tolds this ti your good friend and co-author Jimmy Moore??

  36. If I can only have 20 grams of carbs (80 calories) and 60 grams of protein (240 calories) how could I possibly eat enough calories without added fat/fat bombs. Even eating fatty sausage, bacon and steaks, the fat on my meat is not enough to get me to an acceptable 1600-2000 calories per day. I need 150-175 grams of fat per day to get adequate calories.

  37. Rats! I thought fat bombs and BPC were a good way to top off the day so I would stay satiated longer.

  38. Claudia Wheeler

    What about eating too little, starvation mode, and wrecking your metabolism? Is it ok to just eat 1,000 or so calories a day when doing IF 16/8? I have found that I’m just not hungry but have heard and read so many times that you should never eat only 1,000 cals a day. It’s all so confusing. This article really hit home because for a long time I was adding more fat to meet my fat macros for the day even though I wasn’t even hungry. Guess what? I gained weight. Now I have more weight to lose than when I started.
    On my new plan that I started recently, I eat breakfast when I get hungry. I often have a smoothie with 1 cup of raw milk, 3 strawberries or tiny bit of blueberries, collagen hydrolosate gelatin powder 2T, a raw egg yolk, some greens like spinach or kale or sometimes not, sometimes coconut oil. Is this an ok meal on LCHF? I can’t tell you the amount of times I’ve been told not to have milk (too carby) and I guess the strawberries might need to be eliminated for weight loss. But really? It’s 3 small strawberries! LOL. Would love to hear some answers to this! I’ve read other people’s questions and saw a few women who posted about eating very few calories and whether that is actually harmful.

    • Stephen T

      Claudia, eating when you’re not hungry makes no sense. The main reason LCHF works is that we’re not hungry, so eat less. Lower carbs means lower insulin when we do eat, and fasting means longer periods without insulin.

      I don’t know about some of the things you list in your breakfast, but three strawberries isn’t a worry, particularly after a fast. I have full fat yoghurt with 6 – 8 rasperies, usually after 11.00 a.m. I drink some coconut oil every morning and afternoon. It’s easy to obsess needlessly. I’m not overweight, so maybe I have more leeway, but low carb doesn’t mean no carb and I never count calories. I only use milk (full fat) in my coffee and don’t worry about it.

      We’re all starting from different positions and perhaps different aims. Mine was good health and I dropped 10 llbs almost accidentally because I wasn’t hungry on low carb and stopped eating three meals a day for the first time in my adult life. After a couple of years, I added relatively short fasts of 16 hours most days. I really think it’s about finding a sustainable pattern of low carb, and perhaps fasting, that works for us.

      I can’t answer your question about just eating 1,000 calories because it’s beyond my experience. If that’s truly what your appetite dictates, I’d just make sure you’re getting enough vitamins and nutrients.

      • Claudia Wheeler

        Thanks Stephen, I appreciate the response. I don’t like to count calories but I do a check in once in awhile to see what I’m eating and where I am. Since I gained weight in the last year, kind of unexpectedly, I recently checked in. I seem to fall around 1,000 calories. Because I have heard so often that you shouldn’t eat so little, I was sometimes making myself eat more even when not hungry. I also had not eaten any fruit (not even a few berries) for many years as I was doing very low carb (and not seeing any results). The strawberries are kind of a new thing with the smoothie I”m having. It’s a bit more carbs than I had been doing. I’m going to do the IF now with perhaps a window of eating from noon-6pm. For weight loss, I would guess I would just do that every day until I get to my goal. I have about 15 lbs to lose now. Before this past year’s weight gain, I was only trying to lose about 8-10 and getting nowhere. I was a little scared about doing IF because I heard it’s bad for the adrenals and I have some issues there with low cortisol in the morning (when it should be high). I just don’t want to make things worse for myself. But doing the IF will be easy enough for me as I don’t have cravings or that much hunger since eating LCHF for many years. I think I must have been too high fat for me, or eating when not hungry, and perhaps that’s why I gained weight instead of losing. It’s all pretty tricky, to be honest.

        • Stephen T

          Claudia, you’re doing very well as far as I can see.

          The problem with LCHF and IF is that it’s not as simple a message as “Eat less, move more”, which is dumb but easy to understand. And that’s its appeal. The problem, of course, is that it doesn’t work.

          Low carb made me feel much better and put me firmly in control of my appetite. However, fasting made me constipated and I couldn’t get much advice on this, except to drink more water. LCHF + IF involves a bit of awareness and some trial and error.

          • Claudia Wheeler

            Thanks Stephen. Did fasting the 16/8 way also make you constipated or do you mean when fasting for several days? I would not want to ever get constipated. I only had one bad experience with constipation after the birth of my son and it was a nightmare. I think the fat in LCHF always keeps things regular. And magnesium certainly helps.

        • Claudia,if your body is in fat burning mode instead of sugar burning, then you don’t need to worry about ingesting only 1000 calories. Your body will get the rest of it’s energy needs from your fat stores. Fasting gets you into fat burning fairly quickly so long fasts of multiple days really are not starvation but your body is silently happily burning through its reserves. Just because we can’t see it happening doesn’t mean our only energy is coming from what we eat daily. It comes from what we have already eaten months and years in the past.

          • Claudia Wheeler

            Thanks Abi. I’ve gone two days now. First day was 16/8 IF and second day I did 18/6. I think I can do either of those fairly easily most days of the week. But, this Sunday, for example, I will be out of the house early and not back until late so I prefer to eat before I leave the house because I have access to better LCHF foods while at home. So, I won’t be able to do the IF that day. I have fasted 3 days other years and lost weight, just a little. I did a cleanse that time. But I gained the weight right back as soon as I went back to my normal LCHF.
            I don’t really want to fast for days, though, right now. Do people successfully just do the 16/8 or even the 18/6 or some variation of that….to lose weight? I’m comfortable doing it this way, but at the moment I don’t want to do more. It’s been a rough year for me; I keep getting sick with stuff the kids are bringing home. So I just feel kind of weak right now. It’s not the right time to do 24 hr or more fast. Thanks for your input.

    • I am presently following the 8 week Blood Sugar Diet – the book that Dr Fung claimed ‘one of the most important books of the year (2016)’:
      According the Newcastle study and from the book by Dr Mosley – fast is sometimes better!
      In my focus to lower A1C to below 5.4 from a recent reading of 6.1, I will follow this and have no worry that it will be wreaking havoc on my metabolism. Along with 800 calories, I include intermittent fasting – generally 20/4. Some days I am slightly over in calories, but I have been combining both low carb/high fat/intermittent fasting for a long time now and have been successful to drop A1C from high of 7.2 to 6.1, and weight loss of 45 pounds. In my final push to lower A1C further, my 800 calorie days include eating LCHF. It has been a long time coming, and I look forward to ‘maintenance’ where I have a little more leeway to include some higher carb intake with good whole foods including fruits, all while ensuring my A1C stays low. I must be very IR as it seems to take me so long. But I feel better today than a few years ago, have dropped weight substantially, would like to drop at least 20 more pounds, and look forward to not worrying about blood sugar levels.
      I don’t generally believe in counting calories, but will be for these 8 weeks!

      • Linda, you are really doing great. Congrats. What does it say about maintenance in the book? How do you transition from 800 calories to eating more normally? Still LCHF in maintenance? And do you still continue with IF in maintenance? Does this diet eliminate fruit entirely?

  39. Charlene

    Excellent post Dr Fung.

    My thoughts are along these lines: if we are switching our bodies from burning sugar to burning fat, then tis best to pull from our fat stores rather than a recently ingested fat bomb. Why would our body take fat out of our fat stores to use for energy if a boatload was just ingested? If I ever get to the point when I want to stop losing weight (cannot imagine that) then fat bombs might be a good idea.

    Thank you for this blog and this website, and a great big, mighty thank you for putting this out there for free.

    • Geez!!! Like he said, he’d thought it would have been common sense.

  40. I am a bit skeptical of the whole “eat until you are full” concept. If someone is leptin resistant, then their ability to sense satiety is impaired. Wouldn’t it make sense to monitor and control caloric intake, even in the context of a LCHF/IF approach?

  41. I think this is very simple. Follow a low carb high fat diet. Less than 20-30 grams of carbs a day. Moderate your protein. 70 to 80% percent in good fats.

    Eat slowly and wait a bit before going up for that 2nd plate. Give your body a chance to recognize it’s full.

    Don’t snack.

    Drink lots of water.

    If you are having a hard time losing weight don’t add or subtract from the food ratio, just fast more.

    FAST. That really is the key.

    • Claudia Wheeler

      Hi, Sue, That sounds good. What about when you are done losing? How do you eat then so as not to gain weight? I would think that if you fast a lot, and then stop fasting and just eat every day, you might gain weight. I once did a 500 calorie a day diet, a few years ago, in desperation to lose weight. I lost the weight fairly quickly, went back to eating LCHF (same ratios you suggest above) and slowly gained all the weight back. It’s not like I ate junk or anything; I just went back to LCHF. Do we have to adopt IF forever? Even after we lose the weight? Thanks for any advice

      • Sue and Tony

        My opinion on this, based on what I have understood from Dr. Fung’s work is this; eating 500 calories a day sounds too much like calories in calories out which directly impacts your metabolism. When you fast, which mean nothing to eat at all, it actually speeds up your metabolism because your body switches over to feeding off of it’s self therefore you are getting an unlimited amount of “food”. Your growth hormones speed up too. Like I said before, it really is very simple, people (me included at first) seem to need to make it more complicated than it is. Feed yourself until you are satisfied and full. Then fast. I think in the beginning and the more unhealthy you are, you will need to fast more than you eat. As time goes on and when you have healed you can eat more than you fast, but yes, I believe we will always need to fast even when we are done losing. If you haven’t already I highly recommend reading The Complete Guide to Fasting. Excellent read. Hope that helps some Claudia.

        • Claudia Wheeler

          Thanks Sue! It is hard to wrap my head around it! I agree that the 500 calorie thing wasn’t good. I was in desperate mode and I’ve regretted it ever since. I felt that I did damage my metabolism. It’s been years, though, and I do feel my body healed itself somewhat since then. Still, I wonder if by eating so much less on a fasting way of eating–because you are fasting a lot–you are training your body to always eat that amount and when you eat more, you will then gain. Sorry, you probably answered that already, but I am honestly afraid of that happening again. Is The Complete Guide to Fasting by Dr. Fung or someone else? I’m definitely going to read more about it. I did start today. I didn’t eat until 12:30pm (did have coffee with cream like Dr. Fung says is ok) and stopped eating at 6:30, two meals, maybe a few nuts in between. Not sure about having a snack. Still researching all this.

          • Yes, Complete Guide to Fasting and The Obesity Code are both Dr. Fung’s books and truly worth getting and reading…. and then reading again. NO NUTS!!! LOL and even though Dr. Fung “allows” the cream really and truly, if you want to heal and lose weight just fast completely when you are fasting and eat, completely when you eat. You have to understand when you give your body a “little” food it sends a signal that maybe there isn’t enough food and that sets up a whole hormonal response (that keeps weight on). That’s why it’s so important to eat well and until you are satisfied when you do eat because that sends a signal to your body to relax… all is OK. Sometimes when you allow yourself some cream and some nuts it’s a slippery slope. It’s almost easier to just say, no food of any kind until I decide to eat. Please get the books and read them. When you understand the science behind it it really is easier to stay the course.

        • I agree! I just finished the guide to fasting and am on my 4th day of water , coffee and broth only fasting. Iam very resistant and have been doing 20-22 hours imf for a few months. I want a faster more healing solution so bought and read his new book. Iam loving it and feel great. I never thought I could go this long but after the first couple days its not hard and I feel so much better in mind and body. My back issues were becoming a problem and I knew I had to get this trunk weight off once and for all. And my fasting BS this am was 90! I couldnt get it to go below 115 for a long time. Success toward really healing. I recommend reading his new book, it tells you how to fast, when to do longer ones for more resistant people and whatnot. A great read.

      • Stephen T

        Claudia, it’s not about starving yourself. Eat your two meals and a snack, which is my pattern, and have a 16 hour fast. Mine’s a 7×11 fast most days. The LCHF way of eating should mean you’re not hungry and the IF keeps your insulin low for longer. I lost 10Ilbs eating this way and my weight hasn’t changed since. I think I must be at my natural weight.

        I do not intend to ever change the way I eat because I like it and find my shortish fasts sustainable. It’s about finding a pattern that you can stick to. Extreme diets, on and off, Yo-Yo diets are going to fail. If you hit your best weight, you need to sustain it. I think you’re still in the traditional weight up and down mentality of dieting. My weight just doesn’t change much and I’m happy with that I don’t fret at all. It’s not a diet, but rather a permanent way of eating healthily.

        You’re clearly anxious about this, so I’d suggest gradually working your way through back through Dr Fung’s weekly blog entries on here or buying his books. The more knowledgeable you become, the more confident you’ll become. It’s really simple – LCHF + IF, with a bit of tinkering here and there to find what works for you. Keep your thinking on these simple principles.

        • Yes. Don’t make it complicated. Sometimes I think the worry that people do about all of this is half the problem. Good advice!

          • Claudia Wheeler

            OK, thanks! Yes, I don’t think worrying is good for my stress levels, LOL. I am def. never changing LCHF. I’ve been doing it for probably about 7 years now. It’s just that every time I did lose weight, I gained it back. This last time I gained it back and now have added more. I didn’t gain the weight eating the SAD way, though. I just want that to be clear. I’m all about maintaining my weight loss. I just don’t seem to be able to do that. So that’s where the worry is. I don’t want this to be yet another one of those things I try….lose weight….but then I decide I don’t want to IF anymore and just eat LCHF, and gain all the weight back, etc. I want to get off that yo-yo thing. I honestly can’t understand what I did so wrong along the way, except maybe the fat bombs like Dr. Fung is saying, or trying to get to a fat percentage and eating more fat even when not hungry. I guess that is what happened. I just want to get it right now….and for good :). Thanks for your help. You are making it sound more simple, less complicated.

  42. So low fat??
    What is moderate?
    What is Dr Fungs macro recommendation??

    • Frank, he’s never once said, ‘low fat’. He’s talking about those who think it’s a good idea to add fat bombs on top of the high fat way of eating he recommends. Eat Low Carb, High Fat and moderate protein and you’ll be fine. If you get stalled or have blood sugar issues, then add a day or two of fasting to bring your glucose down. All the best.

  43. It’s working! 16/8 most days, one days was 18/6. I’m losing again! Amazing.

  44. What you’re saying makes sense, and I truly enjoy your humor.

    In addition to fasting, is there a way to improve leptin sensitivity? (the way Cinnamon & Turmeric, or Chromium & Vanadium are reputed to improve insulin sensitivity).

    Since adopting this low carb lifestyle, I have cut carbs to <20g per day (and usually stay under 10), protein is limited to about 80-100 (though a your post from 22 Sep 2016 "how much protein is excessive" leads me to think I should cut that drastically as well).

    But here's the thing… calories, while nothing more than a unit of measure (heat, water, one degree, etc), seem to be helpful in monitoring my intake. I am really fat (I hear Gunnery Sergeant Hartman's voice every time I look in the mirror), and I notice that after cutting carbs down, my weekly caloric deficit roughly tracks the amount of weight I lose. Like one speaker said "calories count, but you don't have to count calories."

  45. Annie Lin

    Thank you very much. One of the best articles on the subject, very clear and to the point!

  46. Pedro Lambareiro

    “What can you do instead? Well, eating more carbs is not a good idea. Neither is eating more protein. Nor is eating more fat. So, what is left? That’s what we call fasting.”

    LCHF took me from 190kgs to 110 but the last 30 were taking a huge time to shed. Fasting solved it and now I’m back loosing 1-1.5kg a week, eating one day, fasting the next.

  47. Brittany

    In 3 months of doing Keto, this is the single clearest, most helpful article/explanation I have come across! Thank you SO MUCH!

  48. Started LCHF/Keto May 15. Lost 16kg in 4 months then hit a wall. Bloods are good and no longer on any meds. Started to rise again late last year and back up by 5kg. This article makes sense but my question is “Can leptin response be restored?” “How?”

  49. shagane sigler

    I wish someone would answer Dana Carpenter’s question about ” FAT FAST” on 1000 cal per day versus water fast advantages. I would like to know if fat fasting on 1000 cal, 90% fat can be done for more than 5 days and if it has the same effect on health.

  50. My apology if the question as already been asked, but I’m a bit confused about this part: ” …therefore does not need any help from insulin signaling and goes directly into fat stores.”
    My understanding was that Lipoprotein Lipase(LP) was required to extract fatty acids from all the different transport systems circulating in the blood(chylomicron, VLDL, LDL, HDL…). But…doesn’t low Insulin levels “turn off” LP???

  51. Haha, i was doing option 2! it’s not common sense. Not when “common sense” has failed you in the past and there are posts like eat more for heat. But thanks for clarifying. Said this way, it makes sense and it’s not common.

  52. 7th paragraph, “You body don’t care.”
    What does this mean?

  53. Marky Whitemurray

    Question. Is a person’s leptin, or leptin resistance genetic or is it possible to reset it? I did not see that in the article.

  54. Excellent article and your points beautifully apply if you’re only talking about weight loss/maintenance. It gets trickier when you’re using LCHF for the purpose of creating KBs to address epilepsy or a reduction of cerebral glucose utilization. I still think weight and health can be beautifully managed even in these instances. It just takes a bit more vigilance and monitoring.

  55. OMG FINALLY!!! My sister (rip) could never understand what my PROBLEM was and I couldn’t do anything but tell her that the “you won’t be hungry so you won’t want to eat” thing did NOT WORK. Now I understand WHY!

  56. High school English class

    This is terribly written. You contradict your own points all over the place, and it’s therefore impossible to find a coherent thesis.

  57. Debra Arck

    The “PROBLEM” is, I am almost never hungry on low carb. RARELY, in fact. If left to eating only until comfortably full, I would – or could – have such a low caloric intake, that I keep hearing I will go into “fast” mode, that my metabolism will drop so low, etc., etc. I find there are many days that a mere 700-900 calories is more than enough. But again, I worry that is too little an intake.

    I am nearing 66 yrs old, and have, so far, dumped over 100 lbs on low carb/keto, with another 105-110 to go. I started about 13 months ago.

    My physical activity is relatively the same — I walk my dog 1-2 times a day every day. (Note that I have mobility – not weight related – issues, so doing more is not something likely to happen for a while, if ever.)

    That said, I did a 7-day egg fast, which amounted to roughly 200-300 more calories per day, as well as more than a10% increase in fat consumption (from about 70% to 83-85%). Yet, the times I did this egg fast plan, I lost over 4 lbs that week, whereas my “usual” very low carb/keto sees a 0.5 to 3 pound weekly loss, though usually a pound or a pound-and-a-half; now and then I see that mere 1/2 pound in a week.

    I am so incredibly confused. Do I up the fat consumption for quicker weight and fat loss? Or do I lower the fat? Or…?

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