The #1 rule of fasting

As we start the new year, many people are looking to lose weight. Fasting, the voluntary abstention from eating is an ancient weight loss method with a long track record of success. However, many people forget the cardinal rule of fasting, or indeed, of any kind of dietary change – always make sure you are doing it safely.

I highly recommend a great new documentary now available for purchase/ rent online called Fasting – The Movie. It presents the science of fasting and how people can lose weight and even reverse many metabolic diseases such as type 2 diabetes and its related conditions. Given the importance of these diseases in modern day medicine, this is nothing short of revolutionary. However, taken to an extreme, fasting can also have its dangers. This is true not just for fasting but for anything. If you take veganism to an extreme, you may put yourself in danger, for example, of vitamin B12 deficiency. If you take the low fat diet to an extreme, you are at danger of vitamin D deficiency. If you take salt restriction to an extreme, you may be at danger of volume depletion. If you take exercise to an extreme, you may put yourself at danger of rhabdomyolysis (muscle breakdown). Everything must be done responsibly, with knowledge and with common sense.

Fasting is no different. Because fasting is already more intensive than most diets, taking fasting to an extreme can be problematic. The movie goes into some of the dangers of fasting and explores many of the variants of fasting that are popular and may be beneficial for people. Simply put, fasting is a weapon to be used in the fight against obesity related conditions and perhaps some aging related conditions.

But, like any weapon, it has two edges. It has real power, and that power can be used constructively and it can also, in the wrong hands, be used destructively. It is all a matter of context and applicability. Much of the resurgence of interest in fasting as a therapeutic option centers around intermittent fasting – generally of shorter duration done consistently and frequently. The 5:2 diet, popularized by Dr. Michael Mosley is 2 days of fasting per week, but those ‘fasting’ days still allows 500 calories per day. Time restricted eating such as a 16:8 schedule, allows you to eat during only 8 hours of the day, so 16 hours are spent fasting. Many  of the patients in my Intensive Dietary Management program use 24 hour to 36 hour fasts 2-3 times per week, and this is done under medical supervision with their physician.

Certainly I use extended fasting as well, but generally limited to 7-14 days, only in the appropriate person and with supervision. Clients are always instructed to stop immediately if not feeling well, and we also check in with them regularly. Longer fasts have more power, but more risk. To me, there is no reason to fast for 30 consecutive days just for the sake of argument. Why not do 4 separate 7-day fasts instead? It will have roughly the same beneficial health effects with far less risk.

By contrast, in Fasting – the movie, director Doug Orchard tells the story of a young lady who decided to join a 30 day water-only fasting retreat. As far as I can tell, there was no medical supervision, and there was no bloodwork being checked and there was no professional who even determined whether this was appropriate. One of my primary rules for fasting is that if somebody is underweight or there is concern about malnutrition, then they should not fast. Underweight is defined by Body Mass Index < 18.5, but for a margin of safety, I don’t recommend that anybody fast longer than 24 hours if they have a BMI< 20. The reasoning seems rather obvious. During the fasting period, the body must survive on the nutrients and energy stored. If you have lots and lots of body fat (stored food energy), then you should be fine. If you do NOT have lots and lots of body fat, then it’s NOT fine. It’s stupid.

People get into trouble with extended fasts because they don’t follow common sense. Many of these fasting retreats offer 30 day water only fasts. If you become depleted of sodium (quite common), there are no doctors there to monitor for warning signs. If you become very weak and unable to get out of bed, there is very clearly something wrong, and you should not continue fasting. This is common sense. In my IDM program, clients know that they may feel hungry, maybe a little irritable, constipated perhaps, but they should not feel UNWELL. If you are really feeling poorly, you must stop. There is no reason to continue, because fasting is free. It is far better to stop and try it again (if you want) in a few days when you are feeling better. The problem with these fasting retreats is that people have paid money to be there and therefore they push on far beyond the limits of good safety practice and far beyond the limits of common sense.

Further, people undertake extreme fasting without any kind of preparation. Instead of undertaking shorter fasts and gradually extending it, they immediately opt for a full on water-only extended fast. This is like a rookie mountaineer that decides that he/she will tackle Mount Everest, without oxygen and push on to the summit irregardless of weather. The experience mountaineer would immediately recognize this as a death wish, but the rookie has no inkling of the dangers and may come home in a body bag. It’s pure stupidity. Yet fasting clinics promote this very same idea. Taking the most extreme fast (water-only fasting, as opposed to allowing some bone broth or some caloric intake), to an extended period of time (30 days instead of 1-2 days), in anybody irregardless of whether this is medically appropriate, without any adequate medical supervision or access to bloodwork? I can tell you right now, that’s pure stupidity.

Marathon

A recent article in the New York Post “Is this the most dangerous diet ever?” tells of a man who, in an attempt to lose weight, decided that he would fast for 47 days. At day 5 he was feeling great. At day 28, he was so weak that he could hardly get out of bed. NOT smart. This is NOT something that I would advise. The Daily Mail shared similar concerns in its own article.

Consider the story of the marathon. According to legend, in 490 BC the Greek soldier Pheidippides ran approximately 26 miles from the battlefield near the town of Marathon to Athens to deliver the news of the defeat of the Persians. He shouted Niki! (Victory) and then promptly keeled over and died.

Suppose a sedentary, middle aged, out of shape man decided to run a full 26 miles at maximum speed tomorrow, without any type of preparation or knowledge. He might very well keel over and die, too. Indeed, in 2014, a 42 year old man died after the London Marathon, the event’s second death in 3 years. Later that year, a 31 year old man and a 35 year old man died in a North Carolina event. Since marathon is a relatively extreme event for most people, it takes some preparation to do safely. That’s easy to understand so you don’t see hysterical headlines saying “Running, the most dangerous thing ever”. If you want to run a few minutes, that probably won’t kill you. Running a marathon in an untrained state could very well do so.

So the bottom line is that fasting, done properly and with knowledge and experience is a powerful tool in the fight against metabolic disease and obesity. But tools can cut both ways and can sometimes harm the user. A chainsaw is a powerful tool for cutting trees. It may also kill you if used improperly. But the proper lesson is not to abandon the chainsaw. Instead, we need to learn how to properly use the tool. Fasting, used responsibly can be a powerful force for health. Fasting, used inappropriately can hurt or kill you. Fasting by starting out skipping a meal here and there – good idea. Fasting by starting out 30 day water only fast come hell or high water – bad idea. There’s a ton of free information on fasting that I‘ve written extensively on my blog. Just search for the 40+ posts I’ve labelled with ‘Fasting’. I’ve also posted free videos and podcasts, too. So cost is not an issue. Be safe, everybody.

 

2018-01-02T10:22:30+00:00111 Comments

About the Author:

Dr. Fung is a Toronto based kidney specialist, having graduated from the University of Toronto and finishing his medical specialty at the University of California, Los Angeles in 2001. He is the author of the bestsellers ‘The Obesity Code’ and ‘The Complete Guide to Fasting’. He has pioneered the use of therapeutic fasting for weight loss and type 2 diabetes reversal in his IDM clinic.

111
Leave a Reply

avatar
43 Comment threads
68 Thread replies
41 Followers
 
Most reacted comment
Hottest comment thread
74 Comment authors
Jerry WarrenDebbie SimonRudy CarreraDanSilviopina Recent comment authors
  Subscribe  
newest oldest most voted
Notify of
David
Guest
David

First off, thank you for your leadership and dedication to reversing diabetes. A preliminary step towards longer IF and 4 to 7 day fasts is intermittent eating and eating only when hungry and only consuming to saiety. In my opinion structured meal times driven by the industrial revolution and especially the emphasis on breakfast as the more important meal of the day has disrupted normal metabolism.

Nikolay
Guest
Nikolay

Thank you! A very good article – fasting should be used for healing not for damage. I got couple questions though:
1) wouldn’t incorporating bone broth negate the benefits of autophagy? Or trigger some sort of insulin response?

2) what counts as preparation for an extended fast? What is the best way to do it? What should be monitored in the blood work?

3) would incorporating longer fast into ADF routine be beneficial or lead to the slow down of metabolism?

Thanks

Nikolay

Debbie Simon
Guest
Debbie Simon

Hi Nikolay! In case you’re still wondering this — Re: will bone broth negate the benefits of fasting: 1) Eating more than 15 grams of protein a day will stop autophagy, until the protein you’ve eaten is used up. Then autophagy will resume. (Eating less than 15 won’t stop it, according to the studies I’ve read.) 2) 15 grams of protein is not enough to trigger an insulin response. 3) Eating that much (little) protein won’t stop stop ketosis, and won’t interfere with weight loss. I’ll sometimes eat three egg yolks when I’m fasting (in a day). They have 2.5… Read more »

Pete
Guest
Pete

1. Bone broth wills top autophagy, but not lipolysis (fat burning). 2. Getting fat adapted will may fasting much easier (i.e. learn to burn fat for fuel instead of sugars), 3. If you are burning fat for energy, longer fasts mean you draw out stored fats for energy, so BMR never slows, in fact it can speed up.

Roberta Corcoran-Andrasik
Guest
Roberta Corcoran-Andrasik

Yes. Ok. But what is a good next step if, despite clean fasting for weeks and months and achieving ketosis and staying in ketosis with no problem across that time, one just doesn’t convert to fat burning? One fails to lose weight at a nice, slow, steady pace? I am at the point of considering that an extended fast is going to be needed and perhaps repeated on some sort of schedule.

JohnM
Guest
JohnM

Ketosis is fat burning.

If ones BMI remains over 25, adding an extended fast to break a plateau, increasing fast variability to keep the body guessing and carefully reevaluating adherence make sense.

If already at or near the bottom of the BMI healthy range, carefully reassessing ones goals and replacing rough qualitative measures (such as appearance, and how clothes fit) with quantitative ones that compare ones health to defined standards becomes increasingly important.

Lori Sherman-Appel
Guest
Lori Sherman-Appel

Dr. Fung, I have tried to obtain answers to my questions about my current difficulties related to how I do IF 16:8 usually 4-5 days/week & follow ketogenic WOE. I follow moderate protein, hi fat, very low carbs. The big difference is I have T1D, taking 1basal & ac boluses, although extremely low doses since pancreas transplant. I have been on Synthroid X30 yrs, with blood work q3-4 weeks. I keep gaining weight while trying to lose. Don’t know what I’m doing wrong. My endo is not familiar with fasting or ketogenic diet & can’t advise. Please …your thoughts?! Thank… Read more »

Mary
Guest
Mary

Lori—have you contacted Dr Fung’s office and joined his long-distance diet group? There is a charge , and your physician must send test results.

Hap
Guest
Hap

Dr Fung I agree with everything you say in this blog post. People go to extremes with everything….there is something about living on the edge that overcomes certain individuals and that get’s reinforced by media drumbeats and internet chaos. With respect to fasting there’s a safe and common sense way and many irresponsible ways. Tradition takes into account the mistakes of irresponsible practices. Time is an excellent filter for disaster. Fasting is another significant example of how practice precedes theory…..and scientific understanding. Thanks for reminding everyone of the downside of an otherwise excellent practice for health. I run into the… Read more »

Jo O
Guest
Jo O

Somewhere in IDM comments, I thought I read where Jimmie Moore had fasted >30 days. I thought that sounded like anorexia nervosa, in other words extreme.

Hap
Guest
Hap

It probably is extreme. If you look on Rhonda Patrick podcasts…Ray Cronise interview is near the end of at least a 30 day fast. he admits…..that he lost a lot of muscle . It’s an interesting interview and CRonise is extreme….with cold challenge and fasting.

Jimmie Moore is pathetic.

Mrs B
Guest
Mrs B

Yes! My BMI is about 21 at the moment. I have done extended fasts in the past but have recently decided not to fast more than 24 h. I have no weight issue. I have had an aggressive cancer issue over 15 months ago. Great advice, Dr Fung.

Jaz
Guest
Jaz

I just listened to a new interview by Dr Valter Longo. Apart from his Proton 5 day FMD he only recommends 13 hour IF for health and in order to avoid gallstones. He also said most studies show it is better to eat breakfast early and then commence IF. Most people do the opposite incl myself ie IF overnight with no breakfast until later afternoon/evening. In fact eating too early in the day seems to stimulate my hunger to want to eat all day. Something as simple as fasting and yet has so many differing opinions, like diet.

sten bjorsell
Guest
sten bjorsell

Agree. Gallstones are best avoided by GRADUALLY increasing fat in the diet. The low fat diet stalls the flow of bile from the liver and makes the bile thick and prone to crystallize forming stones. Else Longo is sound with lots of trial data behind the science.

Moni
Guest
Moni

LOL. I should have known that when I started LCHF. I never knew I should have increased the fat slowly. Thanks for sharing the information anyway, Sten. 🙂

Mrs B
Guest
Mrs B

I just listened to this whole interview. He sounds like he is pushing his diet, available in a package (proceeds to non profit Create Cures). Other than that he recommends higher carbs, but moderate protein. He reckons safety and compliance are important. He does not support red meat in diet. Refers to Blue Zones. I will stick with water fasting. He also mentions risk of gallstones when skipping breakfast. He reckons there are no long term studies about Keto/LCHF. Meh.

Jan
Guest
Jan

Whenever a person has bariatric surgery they are told there is a risk of gallstones. Due to extended periods without caloric intake. ie fasting. I don’t know the percentage of people it affects, but people are still having this type of surgery. Obviously they don’t tell them they can have the same control and outcomes with IF. But they do tell them before they leave hospital their type 2 diabetes has virtually resolved so patients should be able to work out why that is, for themselves, surely.

Aeowyn
Guest
Aeowyn

Yes, was also confusing to me. First he says, 12+ hrs can cause gallstones, then praises his extended 5 day FMD fast🤕 And saturated fat is unhealthy line has put me off as well. So thank you, I stay with consecutive Dr Fung

Cindi
Guest
Cindi

I didn’t listen to that one but did listen to many others of his. What is important to know about Longo is he only came up with the “fasting mimicking diet” because people are so paranoid about actual fasting. He couldn’t get anybody in the research and medical establishment to take fasting seriously because they thought it was too extreme, and that people would never follow it. So he came up with a diet that best caused the same effects in obese people, once which was more easily accepted. (A low calorie diet with specific macros, for 5 days every… Read more »

Moni
Guest
Moni

Yes, what you say is true. I found an old BBC documentary where Longo looks a lot younger. (“Eat, Fast, Live Longer”. https://documentaryvine.com/video/eat-fast-live-longer/ ). Back then, he used a 4 day water only fast. He modified the fast so hospital patients (sick people) could actually try it. Longo is not a rebel. He is working totally within the medical environment and giving out all the warnings about situations that could happen to only one person out of a thousand who fast (he mentions something like that in an interview). Aside from the galbladder warning, he says skipping breakfast increases the… Read more »

Stephen T
Guest
Stephen T

Jaz, I’m with you. I can easily not eat breakfast, fasting for 16 hours, and breaking my fast for an early lunch at around 11.00 a.m — 12.00 p.m. seems to work for me.

Martin Williams
Guest
Martin Williams

Hello, Jaz. Are you able to supply the source of that Longo interview? Sounds interesting.

Irina Ekpo-Umo
Guest
Irina Ekpo-Umo

Prof. Valter Longo just published his book The Longevity Diet. It is a culmination of 25 years of research by his team and covers nutrition as well as fasting, FMD fasting mimicking diet including.

Will Wilkin
Guest

I saw it on David Perlmutter’s website: https://www.drperlmutter.com/the-empowering-neurologist-david-perlmutter-md-and-dr-valter-longo/ Didn’t watch it because don’t usually have time for videos (I read much faster), but also I lost interest in his new book (The Longevity Diet) and that video because the publisher’s description of Dr. Longo’s book contained the following words, which describes fasting in a way that bears zero relation to my very positive experience of fasting: “The key is combining the healthy everyday eating plan the book outlines, with the scientifically engineered fasting-mimicking diet, or FMD; the FMD, done just 3-4 times a year, does away with the misery and… Read more »

jaz
Guest
jaz
Martin Williams
Guest
Martin Williams

Thanks.

CTYonit
Guest
CTYonit

I cannot say thank you enough– my family is panicked by my fasting. I have no health issues so practice moderate LCHF and IF (16:8 daily and 24 hr fast once a week). I send them as much info as I can–I sure hope they watch the movie.

Lynette
Guest
Lynette

I’ve noticed a kind of competitiveness among the fasting groups I’m in on Facebook. It puts me in mind of the ProAna websites wherein anorexics compete for who can eat the least, weigh the least, etc. That’s not a slam against fasting which, used in the sane, disciplined manner you promote, is almost magical in healing potential. It’s just human nature. Bigger, faster, better than you … which in fasting translates to something which could be dangerous. Blame the users, not the tool. Fasting, as exemplified in your work, is a gift. The community which has developed around the concept,… Read more »

Will Wilkin
Guest

Hi Lynette, I’ve been on a Facebook-fast for 18 months now and it’s an important part of why I feel and live better now. I found FB undermines attention span by slicing it into literally fractions of a second as one constantly scrolls searching for a post they might stop at for 1-3 seconds. Not just attention span but the level of discussion there also tends to be lower than I want. Finally, I highly recommend the book “Complete Guide to Fasting” by Jimmy Moore and Jason Fung. I read it skeptically and for information purposes only, thinking fasting was… Read more »

Srinath
Guest
Srinath

I’ve fasted my way down to ~25% BMI. I have actually lost ~75lb from my start weight. I was at one point 95lb down. However the few stubborn grabs of fat remain around my belly. How to get rid of that. I went to 145 (25lb below my current weight) and still had those. So I know just weight loss wont work.

faithinindia
Member
faithinindia

I think consistent short fasts 18/6 daily for 24/36 2-3 times a week and eating LCHF well in between will do it. but it takes time for the last bit. consistency is key with no cheats. Also, know that if your over 50 its NORMAL to have a little belly fat and is healthy. If you get sick you need the reserves.

Charles
Guest
Charles

Great article. May I suggest it makes more sense to think of IF and TRF as practices that train your body to go without food, rather than weight loss tools? It takes a while to get used to cold weather and other stresses, but handled sensibly and gradually, you can get stronger and more conditioned.

Tomas
Guest
Tomas

I am 37 years old. Type 2 diabetic, 5,11 weight 260 pounds. I started a 30 day water fast plus coffee and tea. 3rd day and im feeling fine. Already good presence of ketones in urine. Because of my being almost 80 pounds over weight will it be safe. I was motivated by. Dr. FUNGS videos and very impressive knowledge. I have bought both of his books and one thing he does not say but implies often is that someone with a lot of excess weight relative healthy could fast for 21 to 30 days with no complications, is this… Read more »

cindy
Guest
cindy

Ketoacidosis occurs when a diabetic person has no insulin on board, so you not only have ketosis from fat burning, but a very elevated blood glucose because of no insulin present. It can eventually result in diabetic coma. In an otherwise overall healthy person such as most of us on here, you don’t get acidosis because your body carefully balances your pH; and as long as you are making insulin, your blood sugar should not get high as some glucose will be available to cells. And as you progress in fasting and insulin resistance decreases, the blood sugar will be… Read more »

meredith
Guest
meredith

Hi there Thomas. I happened to read your post and thought you should read this post on some potential risks associated with fasting- especially long-term fasts & for those with type 2 diabetes. Hope this helps & be safe! http://blog.virtahealth.com/science-of-intermittent-fasting/

JohnM
Guest
JohnM

Sorry but this article reads as deceptive to me (or at least cherry picking what they chose to reveal) under the guise of being authoritive and seemingly thorough. They both know perfectly well that the basis for weight reduction and improving health lies with the 80/20 rule where 80% of the value comes from less than 20% of the effort in otherwise healthy people. They chose instead to focus on the less healthy and to keep the fear factor high. Keep reading and learning Tomas and work very closely with your doctors. If you haven’t already considering buying one or… Read more »

kimberly
Guest
kimberly

Hello, I purchased the Obesity Code and will start intermittent fasting on Monday. My interest in the program was spurred by my desire to lose weight. However, I am a bit confused in the templates offered for the 24 hour protocol. It is set up for four fasts with Sunday and Monday being a fast day. But in other parts of the book, it is suggested to fast 2-3 days per week for weight loss. What I think would work best for me is to fast three days on a set schedule i.e. Monday, Wed., Friday…and try to fit in… Read more »

katy
Guest
katy

Hello Kimberly! I started with the up day down day plan that Dr. Veraday suggests. I was eating the 500 calories on my down day as she suggests. That was a good introduction to fasting. after searching the web I came across the obesity code podcast and very quickly switched from that to a 36 hour fast every other day (with broth and some coconut oil or heavy cream in coffee on my fast day). please look at this as a progressive lifestyle change. Be flexible, I have put two eating days in a row because of an event I… Read more »

cindy
Guest
cindy

If you are just beginning to fast, I think you might consider initially just skipping breakfast, which will give you about an 8 hour eating window, 16 hrs of fasting. Do that for 1 week and see how you feel and what your weight shows you. That’s how I started accidently, on vacation one year, and I lost 10# while on vacation, eating out all the time, eating what I wanted, but only in that 8 hour window. Since reading The Obesity Code, I have increased my fasting window to 20-22 hrs/day. I do have coffee with heavy cream in… Read more »

JohnM
Guest
JohnM

The approach you suggest worked well for me nearly 5 years ago now; having maintained my weight since with an occasional IF. Consistency to establish the initial routine is more important than matching an example template. Fasting for consecutive days shortens the initial transition to fat burning and eliminating hunger. Paraphrasing the comment in both books: “…in 2-3 days most experience complete loss of hunger.” It’s very important to realize that ensuring permanent success requires carefully reconsidering our personal definition of “normal eating”. It is, after all, what got us into weight/health issues in the first place, so it must… Read more »

Erin
Guest
Erin

Do whatever feels right for you! You’ll still get the benefits of fasting no matter how you arrange the days 🙂

Bev
Guest
Bev

I have (quiescent) Ulcerative colitis taking mesalozine for it. Also had to hve a hemi thyroidectomy 6 months ago and don’t need medication for it. Have been on SCD for 3 months but want to begin IF to reduce inflammation…my question is this safe for me to do? GP and GI consultant not interested in supporting me except when I’m in crisis. I used to do keto.

Patel
Guest
Patel

Dr Fung,
Thank you again for so much for so much knowledge via various sources. following your way I am now regular faster unto 10 days and improving my health.. I have question regarding reversing diabetes..lets say after following IF/Keto/extended fasting I manage to reverse my diabetes and if I start eating Carby food with control with IF/EF will my diabetes will come back immediately or will come back slowly? I mean I will have to eat keto diet for rest of my life or I can enjoy freedom in phases?

Deborah Stålek
Guest
Deborah Stålek

I have bought your book the complete guide to fasting, after looking at some of your internet information. I am thrilled that I have already gone down a size in clothing. This is wonderful. I am finally able to lose weight, after 12 years on LCHF diet when I started lost 10 kg but since that have not been able to lose any more. I have noticed that if I wait long enough between meals, that my blood sugar actually becomes normal. If it is high in the morning, I skip breakfast, only drink the broth and water. In the… Read more »

cindy
Guest
cindy

Hi, I have some Bragg Raw Unfiltered (Organic) Apple Cider Vinegar which I got from a health food store. You also might check on Amazon, I think they might sell it. It does make a difference, I think filtering might remove the “mother”.

Marta
Guest
Marta

Deborah, You may not have cooked it enough. I cooked mine for 48 hours in a slow cooker and that worked well however you need to stay on top of the liquid level. I now use an Instant Pot and I cook the bones for two, four hour intervals. Very gelatinous and I think better tasting. The resulting bones are pitted which means to me the minerals have been leached out. As for the vinegar I don’t think it matters too much and as I’m allergic to vinegar I get great results w fresh lemon juice. Your looking for something… Read more »

Donna
Guest
Donna

Hi. Just read The Obesity Factor, which had life-changing information for me. I’ve been working on some fasting and changing to a more low carb/high fat diet. Even though I’ve not been doing it long enough to lose large amounts of weight, I can already tell how much better I’m feeling. During a recent 24-hour fast, i had a feeling of being free! So nice to not feel enslaved to food for a time. I also notice increased energy and a better mood overall. Thank you, Dr. Fung, for providing the information!

Moni
Guest
Moni

It would be important to hear Dr. Fung’s take on several statements Dr. Valter Longo makes on this podcast: https://www.kevinrose.com/single-post/valter-longo (posted by Jaz in another comment on this same entry). He says skipping breakfast is dangerous, fasts longer than 13 hours can cause gallbladder problems, etc. etc. Of course, he’s not a fan of the LCHF diet but his words definitely left me wondering and a bit concerned.

susan Barrett
Guest
susan Barrett

It calmed down my gallbladder, If I eat carbs with fats it really messes it up. I think he is wrong on that.

Pam
Guest

I don’t understand why in the world he would think that fasting longer than 13 hours could possibly lead to gallbladder problems?! Sounds a bit like other docs and dietitians who state their ‘concerns’ about the ketogenic/LCHF diet ‘stressing the organs’, where they specifically talk about the liver and the kidneys! I’ve never seen evidence of this, and he/they are misleading folks, and giving their ‘opinion’ without evidence to back it up. I’ve never heard anyone complain of these complications, or any of the docs using these methods in the clinical practice talking about them being concerning complications, ever. ??… Read more »

cindy
Guest
cindy

When I was in my 30s, after having 3 kids in 4 years (something I don’t recommend), I needed to take off the weight from my pregnancies. This was a couple decades before I had metabolic syndrome and then type II diabetes. Anyway, in my 30s, I did a Medifast diet at a local hospital-it was medically supervised and I was seen weekly, had EKGs and labwork done periodically, and VS and weight weekly when I was seen. This was hi protein, ~500 or 600 cal/day in 3 shakes. I remember it was easy to do and I was not… Read more »

Hap
Guest
Hap

I think Dr Longo has to be very careful what claims are made for his longevity diet and especially the FMD. USC probably owns/licenses the IP and they don’t want the FDA coming down on them before they get a chance to get the diet approved…because that is exactly what it will require if they bundle with conventional cancer therapies. The drug companies will find adding FMD problematic and potentially complicating the results of trials and therapeutic outcomes. As far as him having a conflict of interest….he has done just about everything possible to create some distance between himself and… Read more »

Moni
Guest
Moni

I haven’t either, Pam. But Dr. Fung is right. It’s good to be careful and safe. I don’t know if Dr. Longo quotes any studies or what. The only thing I have read are Volek and Phinney giving out some warnings about loosing muscle mass (which can be prevented through exercise) and also about refeeding carefully. Someone posted the Virta blog entry link in one of the comments here. Take care.

Tracy
Guest
Tracy

Moni, Hap mentioned in one of his posts that the study resulting in the conclusion was a rodent study. Dr. Fung has based all of his research on human studies only, which I really appreciate!.

Will Wilkin
Guest

I started my very-low-carb journey with Volek and Phinney’s books, but experience has shown me there does not have to be any muscle loss with fasting –it hasn’t happened to me. I’m almost as strong as I was in college (when I was weight training) 30 years ago, and definitely I feel healthier than I ever have in my life.

Hap
Guest
Hap

I am now reading Dr Longo’s new book, after listening to the Kevin Rose interview. I think the issues are significant and that Dr Fung should address this. YOu did not mention KD in addition to LCHF (I guess nuances here)…..but a lot of people on this site have replaced their carbohydrates with protein….and here Dr Longo is very adamant….INCREASES in all cause mortality and decreased longevity. Possibly there is a nuance here as well since if diabetic and already running increased ACM but KD reverses the diabetes risk….at same time increasing risk for other reasons…..perhaps this comes out in… Read more »

MikeT
Guest
MikeT

There is a lot of data to shows that in elderly populations, those with higher intakes of protein have better health (lower morbidity, mortality, etc). While imagine this data comes from self reporting, which is notoriously unreliable, it should make one question the idea that low protein is a goal for longevity.

Hap
Guest
Hap

Mike T
Dr longo pays some homage to the need for higher protein in older folks…..but only from .31-.36g per lb body weight. This seems ridiculous. I have come to the conclusion that these recommendations apply primarily to sedentary populations.

Protein estimates for folks on a eriousprogram of strength training and increasing mass is closer to 1 or even 1.5g/ lb.

The big problem would be for getting these levels from plant sources alone…..a longo dictum. Omnivore behavior necessary.

Moni
Guest
Moni

Hi,Hap. Dr. Longo, based on the interview, is a vegan who eats fish. He does not like LCHF or is not well informed about it or the research behind it. Uninformed people usually say LCHF is a high protein diet. It is not. I am tiny and petite. I eat 43 grams a day of protein. Is that high protein? For sure it is not. LCHF is a moderate protein diet. In regards to kidney disease, as far as I have researched, even if someone ate a high protein diet, it is not 100 per cent certain kidneys will be… Read more »

Hap
Guest
Hap

thanks for your thoughts.

Moni
Guest
Moni

Hap, listen to what this expert says regarding protein and kidney damage. He touches the subject around minute 5.00 https://www.youtube.com/watch?v=15jtzjv8uOM

Moni
Guest
Moni

Right here the same specialist (Canadian) talks about diabetics and protein. So this is much closer to your questions, I think. https://www.youtube.com/watch?v=1_MXKahAtAo. Around minute 19.05

Hap
Guest
Hap

Yes and so is Amy Berger helpful on break nutrition podcast.

It’s also possible that other factors tha purported veganish low protein diets responsible for longevity in longo epidemiology studies

Hap
Guest
Hap

I will have to go back to VL book….but the protein issue became so as a result of rodent studies ….and applies to “longevity” but also to an alleged (ok probably almost proven) protective effect of fasting and FMD in achieving excellent response rates to chemo and other therapies in cancer. I don’t remember anything about kidney disease. The Laron folks in Ecuador can eat just about anything and not get cancer or diabetes….many are obese….but have normal if not enhanced insulin sensitivity. What they don’thave is growth hormone. another issue is that if you read Dr Longos book, he… Read more »

Tracy
Guest
Tracy

Hap: Have you ever read the Obesity Code? All of the research in that book was based on HUMAN studies ONLY. So you might do well to check it out.

Moni
Guest
Moni

Hap, thanks for your reply. I am 57 so not young either. And yes, I have read about sarcopenia and the need to increase protein consumption as we age. In those videos I sent you the links for, the nutritionist/dietitian/protein expert says many interesting things about falsehoods regarding protein consumption. About diets and muscle mass loss, that it is a lie that women will have their minerals leached out of the body through higher protein consumption, etc. I found both videos very interesting but particularly the link I sent you below. Animal protein, in particular, has been sent to the… Read more »

Hap
Guest
Hap

Let me restate my personal concern. I am weight training…not exercising. Exercising is getting SHT (sweaty , hot, tired)…that’s not training. I am creating similar conditions to what might be termed a “second growth spurt”. Every week the weight goes up my body responds with an adaptation to meet the higher stress conditions it expects (and will get plus more). This process is highly anabolic, at least with respect to muscle…although the molecular chemistry system wide is also greatly affected. I am asked to consume a lot of protein. Since I am not a skinny teenage boy under testosterone storm… Read more »

Moni
Guest
Moni

Thank you for your reply, Hap. Oh, wow… you are like an athlete, then. I watched several Dr. Longo interviews yesterday on YouTube. Nearly everybody questioned the age related protein issue, but especially Dr. Mercola. He doesn’t appear to believe in all of Dr. Longo’s statements on his book. I find his discoveries amazing regarding what happens in the cells during fasts, autophagy, inhibiting M-Tor, the glucose pathway, etcetera…. This is certainly an interesting time. However, in some sense, it all sounds a bit too theoretical. First, there is the fact of the yeast or rat experiments. There is an… Read more »

Jaz
Guest
Jaz

Here is a documentary of a journalist who did Dr Longo’s FMD if anyone is interested. There is also a transcript of the show. http://www.abc.net.au/catalyst/stories/4485468.htm

Hap
Guest
Hap

Me too.

Eric
Guest
Eric

For me daily 23 hour fasting works. Yes I eat once a day usually 15 minutes so 23 hour and 45 minute daily fast. 365 days a year no breaks.
For me ketogenic ratio 80% fat 16% protein and 4% carbs works.

Disne
Guest
Disne

Eric, If you are eating only 4 % carbs that indicates to me you are not eating enough vegs and fruits. Unlimited carbs from vegs is good for you. Eating mostly mostly meat, cheese and beacon products are bad for us.

Awy
Guest
Awy

Hi….do you drink coffee..tea or any liquids in between and if so do you add cream to it?

Tyler
Guest
Tyler

every meal you eat is 80% fat and 16% protein? What do you eat? Avocados with mayonnaise on top?

Shirley
Guest
Shirley

I plan to start a 7 day fast Monday 1-7-2018! My Dr. told me as a diabetic I should eat one meal a day and use sugar free juices diluted with water! Also to keep a bottle of juice with sugar should I bottom out! Is this the correct way?

sten bjorsell
Guest
sten bjorsell

Forget the sugar, but do only 3 days the first time. Make sure you drink plenty of broth and water a few hours before you eat first meal. If you have lots of energy and low BG, like 60 that I had after 2 days, don’t worry. But if you become weak, stop and start the broth. Salty broth is best!

EVELYN
Guest
EVELYN

you said salty broth is best , would ” it raise ones blood pressure?

sten bjorsell
Guest
sten bjorsell

Read the book titled “The Salt Fix”! The book means that the limitation of salt has killed more people than it has saved, and salt reduction only reduces blood pressure in 1/3 tested! Also, when blood pressure drops from low salt the pulse tend to rise 4 bpm for each mmHg lower blood pressure, which sounds to me as if the pumping effect becomes poor with less salt. I drank a lot of pure water 10 years ago to try to “flush” my system. After several days I noted that my pulse was 110 in the morning, doing nothing! A… Read more »

Duncan
Guest
Duncan

Excellent article

Cari Feldewerth
Guest
Cari Feldewerth

Hx of Type II diabetes. Have kicked it to the curb over the past year (A1C 5.0) using IF and KETO diet. I use a variety of IF methods to fit my lifestyle. Problem is, ALL of my docs think I’m CRAZY and tell me NOT to fast, that it’s unhealthy and slows metabolism. While I know this isn’t true, how the heck do I find a LOCAL doctor who will support my efforts?? My kidneys are producing small amounts of protein which, I’ve been told, is a precursor to kidney failure/disease. While I’m not producing at an alarming rate,… Read more »

Stuart
Guest
Stuart

Hi Cari, you should read this blog article by Dr Michael Eades https://proteinpower.com/drmike/2009/04/19/thiamin-and-diabetic-nephropathy/ regarding a study where over one-third of the participants with diabetic nephropathy completely reversed their proteinuria with 300mg/day of thiamine (Vitamin B1) and the other two-thirds all showed significant improvement. The advice to restrict protein is nonsensical – protein in the urine is a symptom not a cause of diabetic nephropathy. To quote Dr Eades *************************** In people with diabetes, microalbuminuria means the kidneys are starting to develop nephropathy, or pathology (or disease) of the nephron (the basic unit of the kidney). To go back to the… Read more »

sten bjorsell
Guest
sten bjorsell

You may take in too much protein. Reduce to 60 gr/day should be risk-free.
Old keto recipes had way too much protein.

JohnM
Guest
JohnM

Congrats on your phenomenal success and admirable resolve!

This site identifies 8 “keto” doctors in Missouri:

https://ketogenic.com/tools/keto-clinicians-finder/

Found using “keto doctors St. Louis, MO” as a google search phrase.

qofmiwok
Guest
qofmiwok

Great points! My only objection is the arbitrary cut-off point of BMI. BMI is not very useful at lower weights, and a body fat % would be much better. I am below your arbitrary cutoff and believe me, I have plenty of fat! My BMI is thrown off because I am tall and I don’t have much muscle mass. After menopause I found it impossible to keep my weight from creeping up, or take it off when it did. 16/8 worked for a short time then stopped. Reduced calories every day just slowed my metabolism and accomplished nothing. So last… Read more »

SamuelEllisBruce
Guest
SamuelEllisBruce

Once again proof that Dr. Fung is brilliant

mike
Guest
mike

I have been following IF now for over two months with great results. I have been trying to buy a Ketone meter in the Toronto area but so far with no success. Shoppers Drug Mart says that the test strips are on a 2-month back order so they took the meters off the shelves. Does anyone know where i can get this item?

Sanz
Guest
Sanz

Try this website: https://keto-mojo.com

Mary
Guest
Mary

If one has trouble with binging, should one avoid intermittent fasting or work at 16:8, no more?

Elizabeth
Guest
Elizabeth

I have an auto immune disease called pemphigoid. I carried out a 5 day fast with 1 cup of broth a day plus tea and of course lots of water. I fasted for weight loss but a wonderful side effect was that all symptoms of pemphigoid disappeared. My doctor was amazed! It is starting to come back 8 months later and I am about to start another fast so I will see if it goes away again.

Jo O
Guest
Jo O

Should add the titer numbers were 1.0 U and 6.0 U Positive ANA results >3.0 U are associated with the presence of detectable autoantibodies.

Jo O
Guest
Jo O

I was diagnosed with SLE/DIscoid Lupus combo. Suffered with low level to moderate symptoms for 15-20 years. Did the 5:2 fast and within 3 months ANA titers basically dropped to 1.0 from a high of 6.9. It has been five years and I did 5:20 for 4 of those years, switching to intermittent fasting since then (15 hours daily). I have not had a positive ANA since. Full five year remission. Nothing else changed in my diet, lifestyle or health approach.

Sgt E Dickey
Guest
Sgt E Dickey

I feel you are the leader for Diabetics with big problem and to copt out to someone else might be wrong. I am sure you not lean anything from document. On another front, I have ask if you will treat me in your hospital as USA Army insurance will pay for treatment, Yet to have an answer? Thank you Sgt E Dickey

Jill
Guest
Jill

Love the information on this website, thanks for all of the great articles. One thing I noticed here however, I would expect an educated person to know that “irregardless” is not a word.

Tomahawk69
Guest
Tomahawk69

Hi Jill, actually it is a word, although often used incorrectly:
https://www.merriam-webster.com/dictionary/irregardless

Fred Hahn
Guest

Dr. Fung – PLEASE post a blog on fasting and Lyme’s disease. My theory: If fasting boosts the immune system, then perhaps after a time, it can shatter the spirochetes “force fields” and allow the immune system to kill them.

Stuart
Guest
Stuart

Hi Fred, interesting theory. Do you know of anyone who has been able to cure their Lyme by fasting? As a long-term Lyme sufferer I would like to know.

Julia
Guest
Julia

I’ve been fasting 36 to 42 hrs once 1 week for about 6 months now. Recently my cardiologist insisted that a 80mg lipitor protocol with Imdur be undertaken. The 1st week, the fast wasn’t much different, week 2 I was hungry the whole time and felt sick, ending the fast at 38 hrs. Week 3 I just got sick, weak, achy, etc, it’s taken two days to recover. I ended the fast at 36 hrs feeling trembly and that feeling has persisted through today. (2 days post fast) is the statin causing the problem? After CVD diagnosis I really planned… Read more »

Leesa
Guest
Leesa

Julia, statins have so many side effects, including increasing the chance of developing diabetes (especially in women). Aches and pains, liver damage, cognitive issues- I wouldn’t take them for any reason. Have you looked at other ways of lowering your cholesterol- upping your fasting might just take care of the problem. Adding fiber, fish oil, other natural supplements might help too. Here’s an article by Dr. Mercola that explains some of the side effects… https://articles.mercola.com/sites/articles/archive/2016/02/10/5-reasons-why-you-should-not-take-statins.aspx

Janette Luparia
Guest
Janette Luparia

Hi, I used IF to lose weight more than 4 years ago. I currently have my A1C to 5.1 with a goal of under 5. Its working. I no longer snack and feel pretty good. I still have a fair amount of belly fat, I have been unable to achieve the mid-point of NIH healthy weight range. I believe it could be lepton resistance if related to body set weight. Any protocol for the elusive last 10-15 pounds? I have done several fasting protocls, up to 44 hours at a time….and no real loss. Keto adapted, fasting for 4 years,… Read more »

Penny
Guest
Penny

Thank you for the article! Just wanted let you know: irregardless is not a word. Regardless is the word that should be used.

Dan
Guest
Dan

Has Dr. Fung addressed the issue or notion that fasting or rapid weight loss can cause gallstones or gallstone problems?

Kat
Guest
Kat

not really sure how to even do intermittent fasting in the real world. I work 8-5; leaving the house at 7am, not returning until 6pm and occasionally later. The schedule at my job is unpredictable, so I cannot for example be assured that I will have time to eat at any given time. I have one, 30 minute break for lunch (and in theory 2 15 minute breaks but they don’t always happen – and NONE of these breaks, including the lunch, are “scheduled” -they happen when there’s time that day). Can anyone suggest how I could eat within these… Read more »

apitius
Guest
apitius

I am a 67 year old woman weighing about 250 lbs. Last year, I did four 7 day fasts as well as one 10 day fast. All without incident. This January, I did another 7 day fast. I felt great, I took a highly absorbable vitamin/mineral supplement providing at more than the RDI for most micro nutrients designed for post bariatric surgery. So I thought I was being prudent. I did not do this fast or the previous ones with a doctor’s supervision. I have no serious health concerns other than hyperinsulinemia and obesity. Over the last 2 years, I… Read more »

Leslie Davisw
Guest

There is no such word as irregardless. Please correct your rap.

Carol
Guest
Carol

Could you please enlighten me on a concern about fasting? I am interested in knowing how fasting affects the thyriod? If you have hypothyroid disease, can fasting cause problems?

Marinus van Aarle (Manual Osteopath)
Guest

Thanks for putting the focus of this article on safety. One preventable death is one too many. And there are too many people putting themselves at risk driven by an ideal body-image profiled in the media.

Della
Guest
Della

I have never felt so empowered in my entire life. I am on my first extended fast after practicing KETO since FEB 1, and 2 weeks prior starting my sugar/carb removal from my diet. During this fast, I feel alive more than I ever have. On my own I only want to extend to 4-5 days, I won’t make it this time due to a work dinner and people are already freaking out I am not eating ( I work in hospice care). But I feel fantastic. So today will be 72 hours. I am so thankful for this information… Read more »

Silviopina
Guest
Silviopina

This trailer (have not seen the doc yet) is a GREAT TOOL for introducing fasting to your skeptical friends. Does anyone here know what good resources exist in Italian? I live in LA, but am from Italy and of course I am familiar w Dr Valter Longo’s work, but was wondering what resources if any would Dr Fung and his team here point me to to help me with my Italian peeps. My mom was asking for a friend and I need some good solid links I can forward that drive the point of “IF” home. I don’t think this… Read more »

Dan
Guest
Dan

I’ve been practicing IF 16:8 and on and off keto (occasional cheats) for about a year. I’m interested in undertaking an extended fast, thus far only gone as far as 36 hours. If I’m planning on including bone broth in my fast, when should I begin taking it, and how much? I’m seeing a lot of conflicting information about the quantity and when to utilize.

Rudy Carrera
Guest
Rudy Carrera

Dr Fung, would water fasting be beneficial to someone who suffers from Crohn’s Disease?

Jerry Warren
Guest
Jerry Warren

Why does my bs go up after 16hour fast 154 before bed 221 in the morning