How to maximize fat burning

How do you maximize fat burning? What should you eat – or not eat? Watch and find out.

This is the second part of our video series with Dr. Jason Fung – now free to watch for everyone. The first part is also freely available to anyone.

Start your free membership trial in a minute and you can watch all seven parts instantly – as well as many other video courses, movies, interviews, presentations, Q&A with experts, our awesome low-carb and keto meal planner, etc.


What is Fasting? – Dr. Jason Fung
How to Maximize Fat Burning – Dr. Jason Fung
How to Fast – The Different Options – Dr. Jason Fung
The 7 Benefits of Fasting – Dr. Jason Fung
The Top 5 Myths of Fasting – Dr. Jason Fung
Breakfast! Is It Really That Important? – Dr. Jason Fung
The Most Common Questions – Dr. Jason Fung
5 Tips to Make Fasting Easier – Dr. Jason Fung
How to Get Started with Fasting – Dr. Jason Fung
The Power of a 7–Day Fast – Dr. Jason Fung
Who Is Dr. Jason Fung?


Intermittent Fasting for Beginners

More with Dr. Fung

The Perfect Treatment for Weight Loss and Diabetes – Dr. Jason Fung
The 2 big lies of type 2 diabetes – Dr. Jason Fung
The Key to Obesity – Dr. Jason Fung
Ask Dr. Jason Fung
Dr. Fung’s blog:


  1. MarciOnline
    Jimmy Moore's Dexa scan just happened this morning. To summarize, Jimmy suffered heart arrythmias, high blood sugar and now we learn he lost 10 pounds of fat - but also 10 pounds of muscle, mostly in his core/abs section. I want to look into fasting, but it seems like Dr. Fung's protocol has actually made Jimmy sicker - with high blood sugars & ironically making him fatter in the visceral area through muscle loss.

    What does Dr, Fung have to say about this? I'd be terrified to end up skinny-fat and actually end up increasing visceral fat in the abdomen with his system! I'm not against Dr. Fung, but Jimmy's results have really scared me now.

    Replies: #2, #3, #17
  2. I think it's pretty clear that if you completely fast 28 out of 31 days in January like Jimmy, you'll absolutely lose a significant amount of muscle mass too, not just fat. That should be expected.

    However, 10 pounds of fat lost hardly equals "increasing abdominal fat", but should indicate the opposite.

    Finally, Jimmy has been struggling with extreme excess weight his entire adult life, no doubt due in large part to unfortunate genetics. Fortunately most of us – almost all of us – have a much easier time reaching normal weight.

  3. Apicius
    Marci, calm down. I can tell you that for me, the LCHF diet and fasting protocol has been a god send. I'm so happy I discovered this information. I have become so much healthier, and it also feels like I'm happier, more energetic and mentally more sharp. My friends and family are astonished at how I look. And I did it without the hundreds of hours of exercise (torture I used to put myself through) and I eat until satiety...the fasting hours fly by, and I don't even notice the meals I skip. I only eat breakfast and no lunch. Sometimes for dinner all I eat is a couple of pieces of cheese, or some olives, some tea and that's it. It's incredible how I'm not hungry anymore. I used to think of food all day...wanted to chew my arm off. Today, with LCHF and fasting...I'm a new healthy and in control being.
  4. Chad
    Are Dr. Fung's hypotheses (you don't lose muscle even with extended fasts) proven? I think not. Has Dr. Fung tested his patients that he places on extended fasts with Dexa to monitor their muscle and protein status? I think not.

    How can Diet Doctor promote a physician who is likely causing harm?

    Reply: #5
  5. Is losing a little bit of muscle while losing a lot of fat "causing harm"? Only if people end up underweight, and that is easy to avoid. Just stop fasting.

    I actually think Dr. Fung is sometimes simplifying a little too much in this area. It's clear you lose a little muscle mass during extended fasts, not zero.

  6. Chad
    Jimmy Moore lost 10# of muscle and 10# of fat. That is not "losing a little muscle and a lot of fat," in my opinion. Losing 10# of muscle is causing harm because statistically he will regain the lost weight in fat more than muscle causing his metabolic problems to be worsened.
    Reply: #7
  7. Chad,
    Jimmy Moore is not typical, nor is the fasting schedule he's on (it's very extreme), nor can statistics tell us what will happen in a specific and unique case.
  8. murray
    It seems he lost muscle mass in the abdomen because the muscles no longer had to support so much surplus abdominal weight, with the fat loss. That's hardly shocking. The more interesting question is whether he lost muscle mass in muscles that continued to work at the same level.

    I've not experienced any noticeable loss of muscle mass or loss of strength from fasts; however, my monthly fasts only go for 1-3 days and not 28 days like Jimmy.

  9. 1 comment removed
  10. Matt
    Lchf will lose you the same as hclf if there is a restriction in calories.
    Reply: #15
  11. Furbies
    Fung referred to Krista Varady's ADF study regarding no fat loss while fasting. Why? I don't know. Varady's study only does fasting every other day, and then usually while eating 500kcal on fasting days. That's drastically different than long term fasting that Jimmy did.

    1. Fung's article:

    2. Study referred:

  12. Eric
    Autophagy and removing senescent cells may improve health. Maybe fasting as in alternate day and ketogenic diets improve health in part through the removal of select tissue.


  13. Leah
    What's missing here is a video on BREAKING your fast! What foods, how long before normal eating again, etc. Looking it up on the internet, you get a mess of information. I can't have sugar, and most protocols call for fruit juice. That's impossible for me.

    I'm not talking about the intermittent fasting, I know you just continue to eat normally. I'm talking about a 7 or 10 day fast.

    Reply: #18
  14. Kenon white
    How many calories is considered breaking a fast
  15. Clive phillips
    Calorie counting is the worst possible way to try to lose weight! That's been known since Newburg &Johnson wanted to withdraw their theory paper in the 30s. Any weight(as opposed to fat) is quickly regained because calorie counting sends the body into survival mode. I've lost over three stone(42 lbs+) using lchf and I most likely eat a bucketful of calories each day! I've lost no muscle. I lose 2-3lbs per week which suits me fine. My insulin intake is down from 50 units twice daily to 6-8 units twice daily. My cholesterol is spot on! I eat heartlily whereas on stupid calorie counting the dieter is permanantly struggling. The reason governments don't tell the truth about the fallacy that is calorie counting is because there's a huge industry exploiting it. Wake up son.
  16. Aline
    Hi! What I don't understand yet is why intermittent fasting (like 20 hours fasting, 4 hours (potentially) eating) would make you burn your fat storage. On the graph in the video, we see that the body seems to switch to burning fat after 1 day. Then why would intermittent fasting (thus < 1 day) also make you burn fat?
  17. ShivaD
    I have heard that long term fasting is stressful on the heart and I think the issue was the length of the fast. It is not for everyone and I haven't gotten the impression from Dr. Fung that he promotes fasts of this length, particularly without medical supervision. Losing some muscle may not necessarily be a bad thing if you are shrinking in size overall. Who is to say the body won't replace it or needs to? The body is so dynamic and most try to simplify it to 1+1=2 and that just isn't realistic as we have discovered trying to nail down every aspect of our bodies. If someone falls off and regains weight via unhealthy habits that is more the issue than blaming the fast just like you wouldn't blame calorie restrictions for the same outcome. I wouldn't advocate going past a week personally .
  18. Jan B
    Leah, I've heard eating fermented foods and vegetables are a good way to break a fast. For example, fermented sauerkraut (not cabbage with vinegar) from a health store or Trader Joe's, plain kefir or whole milk yogurt. Then some lightly sauteed greens, also eggs.
  19. Chrissy Stevens
    I am really wanting to join diet doctor but am worried that meal plan will have foods I don't normally eat or can afford is there a way of insuring that I have only foods I would normally eat.
  20. Clelia
    Some time ago I read thay Jimmy Moore walked out of a meeting from Dr Fung and Miss Ramos. He was angry and was disagreable. Since then some people have been trying to discredit Dr Fungs work.
    I am sure been an adult Jimmy Moore, it is his desition to do right for himself. I dont think I have to defend Dr Fung, he does ok for himself.
  21. Mira
    I am confused by the dissimilar information about protein requirements and fasting that are recommended on the Diet Doctor web site.

    This site says to eat enough protein for your body weight or lean body weight, but it also hypes fasting as a way to get past a stall in weight loss or lose more weight. Which is it?

    I know someone who seriously impacted her heart by eating insufficient protein for years in her attempt to lose weight. Obviously, if you fast for a 16/8 cycle or don't eat food at all, you won't be eating your daily requirement for protein.

    Isn't this reduction in protein consumption unhealthy if you follow a fasting regimen off and on for one year?

  22. Rahul
    Nearly a 4 minute video and the relevant point comes in at 3:20!; keep it crisp and lucid guys, spending 4 minutes on a video and making the key point only in the last 20% of it is not winning you a lot of fans. Thanks
  23. Malcolm Stokes

    JUNE 30 MY FASTING BLOOD SUGAR WAS 267. I have been a type 2 diabetic for 14 years and I am taking oral medications daily.I searched the internet for a new idea. Came across your website I did not watch all of the videos but I did decide to try intermittent fasting with 20 minutes of exercise of large muscle groups. I have been a vegetarian/vegan for the last 5years but my bloods sugar was over 200 for the last 8 months.

    July 02 MY FASTING BLOOD SUGAR WAS 188. I did the 16/8 protocol with a salad and steak cooked in butter and olive oil for my two meals. Again I exercised as before but I also added 10 minutes on a bicycle.

    July 04 MY FASTING BLOOD SUGAR WAS 166. Intermittent Fasting with high fat WORKS. NEED I say more?

  24. Nina
    That's what I 've been reading for a few days !!! Thank you for the positive .that stands by what I had been told!!! Great stuff I'm just starting my first16/8 fast ..thank you
  25. Dr Reddy
    Dr Jason, I like your concepts.I think we find the solution for Diabetes. My question is what would we need to look in to down the line in next twenty year who are doing keto diet? Using too much carb diet causing Diabetes to us. Using too much keto diet (fat diet) could cause any disease in long run?
  26. Sandra
    I am 74. I don't exercise other than take my dog out 2 or 3 times a day. I'm active in that I keep moving, cleaning, crafting, tending my plants, etc., but it's not nearly enough. I have fasted since my late 20s. I ALWAYS go more than 5 days because it takes my body that long to get to where I want to be. The first couple of days can be tough, I kept watching videos on fasting and its benefits to keep me motivated. On the 3rd day, hunger pangs dissipated quite a bit -- eating was almost an afterthought. On the 4th day I had short spurts of hunger, but it was easy to focus on something else. What kept me going at this stage was the incredible burst of energy that I felt. I had SO much time on my hands -- something I always forget to calculate. I told my friend that it was the worst part of the entire thing and she asked: "Wow, how much time to you spend eating?" Ha ha. It's not just the eating -- it's the prepping, the shopping, the putting away groceries, cooking, washing dishes, loading/unloading dishwasher, taking out the garbage, cleaning pots and pans, opening the fridge, going into cabinets, drawers, etc., and THEN there's eating. But because my energy level was so high, I started to do more -- walk more, I cleaned my condo like I've never done before, I did things that I haven't taken the time to do like listen to music, go somewhere, walk more, exercised, and by that 5th day -- no hunger, none -- high energy level, thinking becomes very clear, I heard noises I didn't hear before -- I was extremely aware and perceptive, I slept like a baby and almost doubled up on my hours of sleep, I felt calm and so good. I did have a cup of tea with milk a few times along the way, I had my coffee in the morning with sugar and milk, but other than that -- it was water only. As in my previous fasts, I decided to listen to my body and let it tell me when to go off the fast. After 10 days, I didn't miss food or eating -- hunger was nonexistent. But as long as I felt that good, I decided to stay on it. On the 21st day I broke fast when I got a few slight headaches and felt a little lightheaded. I always listen to my body. It sends us signals all the time. I trust it. I hate coming off the fast because I have to remind myself to take it slow, only eat certain foods, etc. So I'm on my 2nd day of "weaning" myself back onto food and I feel absolutely great. I have lost a total of 24 lbs, I am completely detoxified and I feel more alive than I have ever felt, and not just mentally, but physically. I wish I could share that wonderful euphoric feeling of wellness that comes after a fast -- but I don't think there's any other way to achieve it. As far as the neersayers -- they're entitled to their opinions. I, personally, don't give any thought to comments or opinions from people who haven't actually done the deed. If it wasn't for Dr. Fung, I would have been winging it on my own, his words make a lot of sense and he explains everything in layman's terms which I understood. Only after watching his videos, did I learn how the human body handles food at different stages. He was my inspiration for the 21-day fast and I'm grateful for that. I can't wait until the next fast, and Dr. Fung will probably be my motivator again.
    Reply: #27
  27. Jjay
    Sandra ... U are an inspiration for me! Just beginning my journey! Thank you for sharing this! Jjay
  28. Marina De matteis
    A lovely inspirational sharing thank you
  29. Mohammed
    (And it is better for you that ye fast, if ye only knew); Holy Quran (chapter2:184)

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