Dr. Stephen Phinney - 'Metabolic Effects of Fasting: A Two-Edged Sword' 

Thanks doc, but I’ll stick with the incredible results of fasting on my mood, energy levels, muscle maintenance, and fat loss.

I was listening to this to see what's new then the alarm went off when he starts using the Biggest looser example. What the heck!!! That High Carb, Low Fat, extreme exercise practice has got nothing to do with Fasting. Yet he using it as example of how fasting effecting your metabolism?? If anything Dr Fung already explains all these claims by This guy in his many videos. The data this Dr uses are never explained properly or telling us the background & subjects used. If you're using a lean group of people of course you're gonna lost some lean mass compare to the fat ones. And what's wrong with the body recycling the old protein - isn't that autophagy is all about? As Dr Fung said our body is NOT STUPID to store fat as firewood for rainy days but when it needed energy burns a much needed muscles that vitals to find foods instead. And he has experience helps thousands of patients to reverse diabetes & obesity with fasting programs. How many patients or real experience this Dr have himself about fasting as a cure other than reading bias data??? With proper medical supervision a long fast can be a very powerful tool and have been used for centuries. Talking about bias & cognitive dissonance. And so many illogical things he said here that makes me think he's really out to discredit Dr Fung's work. What other data he might be miss uses to represent his speech again then?? I think I will never take this guy advice seriously ever again 😠🙄

I have been on keto OMAD for 8 months and i kept increasing my calorie intake unconsciously from an average of 2000 to more than 3000 and i didn t experience any kind of weight gain. (Also did 3 Times 7 days fasts)

I recently read one of Fung's books. He said something like you don't lose muscle mass because you fast, you lose it because you don't exercise it. I think he points to a study where some resistance training was involved. What's that thing called where two sides have a position and do everything to fit their own heavily invested views? I think Phinney and Fung ought to get together over a glass of dry white wine and be more open to each others ideas.

Amazing talk - short, concise, full of data and scientific references. Excellent job, Dr.Phinney!

I am 5 10. I was 223 lbs. I fasted 3 days a week for 22 hours and ate one long very large meal on fast days. around 3000 calories. I GAINED muscle without working out and lost fat. I went down to 193 in six months and my waist went down 3 inches. I was never hungry. Fasting is awesome.

Dr. Phinney needs to watch the documentary "Science of Fasting". Germany and other countries have done a lot of research on fasting. Russia did a little of fasting during the Cold War years. Most of that research remains untranslated in Russian.

17:01 So when you have a disease where the body produces too much insulin due to insulin resistance (T2 Diabetes) and you adopt a diet that naturally corrects this problem you have issues if you take drugs that artificially manipulate insulin in the body? That really shouldn’t be a surprise to anyone and is not an argument against fasting.

Dramatic calorie restriction plus heavy exercise (arguably to over-training levels) are two relevant elements in the metabolic issues of the participants of The Biggest Loser that were studied.

Conclusion from personal experience, fasting is a tool to calorie restrict , and just like any other weight loss mechanism , one hits plateau and that leads to stricter fasting regimen, which is lower and lower caloric restriction. This creates metabolic damage , weight gain even at maintenance and weight loss difficulty even at cal deficit. I’m glad someone like dr Phinney is bringing countering ideas on IF and longer period fasting to balance all the much hype. Would be glad to see more though studies , as well as gender specific ones. I think studies on both sides of the argument should be encouraged without bias for our greater knowledge,understanding and application.

I was a fasting fan. I started to do OMAD (one meal a day). I did couple of 36 hours after initial keto adaptation. I got to agree with Dr Phinney. In my case, my ketones hit "starvation" levels very quickly, with lowest of 4.7 and as high as 6.2, despite eating normal amount of calories (and carb was 5 to 20gr). I was extatic. knowing that I hit "therapeutic" range with very low glucose in the 60s. But all the magnesium and sodium in the world could not help my horrible side effects...lethargic, sick, bad leg cramps. Now back to 2 meals of keto, no fasting, and I am back to my amazing energy self. Fasting ketosis *can* be an issue for folks like me who are probably not too insulin resistent I guess

Very hard to fault anything of Dr. Phinney's work. One of my favourite LC scientists. Great stuff.

Thank you Dr. Phinney. I lost 50 pounds mainly alternate day fasting. But once I got leaner than I have ever been in my adult life, I could only do OMAD and was beginning to start regaining at my meals size to satiety. I assumed my basal metabolic rate was impaired. So I decided to do add strength training; specifically H.I.T. 2 times per week. I have been at this for about 6 weeks and my weight has come up a bit from my low point but my waist size has been stable. I track my waist size now. Yes, you may need strength training to "rehabilate" your metabolism (increase lean body mass) after fat loss using fasting. Yes, I can never go back to 3 meals a day. My one meal a day is large. On strength training days I do eat eggs before, and then have my meal right after so those days are 2 meals.

Dr. Phinney isn't contradicting anything Dr. Fung says. Dr. Fung says that fasting longer than 3 to 5 days should be done under a Doctor's care because of the adverse effects.

I absolutely love you Dr. Phinney, but I'm going to side with my own results and Dr. Jason Fung on this...

In my descent from 258 to 184 pounds, the most I've actually done is go down to one meal a day; so I am not a fasting fanatic. Possibly it is better to use shorter fasts like what Dr Fung from the "Diabetes Code" book recommends. But, correct me if I am wrong, but the Biggest Loser study was not a fasting study, but caloric restriction; fasting, which from my reading does not affect metabolism as much. For lean body mass loss: we definitely want to lose some, otherwise our skin would be too loose and flappy. When I think of "total fasting" I still drink water with apple cider vinegar and sea salt, in order to keep my sodium up. And I still take all my whole food vitamins, minerals, and magnesium. .. carnitine, CoQ10 ..etc Not related to me, since I was not on any diabetes meds. But, it seems like a study showing higher risk of hypoglycemia for people on meds, would be an indictment of the supervising doctors who failed to monitor the blood sugar levels properly. On the slippery slope segment, I don't think I could get addicted to fasting and want to do it more and more. I like to eat actually. Recent study / video on this topic: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-IF2-MqIGTao.html

1. Biggest looser contestants. Not fasting. Low calorie diet and training. Lowered BMR. The only ones who didnt drop BMR are the ones doing by gastric bypass surgery which effects are similar to fasting. Phinney didn't mention or missed that. 2. Fung said when measuring muscle mass...measure muscle mass and not urea. If Phinneys claimed 1/2 lean mass loss per day was true, me and many others would consist of pure fat. I don't. My muscle mass is the same. 3. The muscle mass loss fear does not fit with evolution of any mammal. Why burn heart and biceps when there is fat? : )

The people in the Big Loser did not fast...they did reduction of calories, which Dr. Fung proved puts you in starvation mode and you burn your muscle.

Adding mineral supplements to a fast is really easy!

The first time I did a 30 hr fast 3 months after starting Keto, my face broke out severely - for almost 3 weeks & very sensitive. Several weeks later I did a 48 hr fast and my face broke out again but less severe. I can only assume this is an inflammatory response from toxin release from stored fat during autophagy. After the 1st fast, I woke up with my eyes & face having fallen on the left side with new wrinkles. My eyes were swollen and I looked like a lion. At the 2nd fast same thing only my eyes were swollen almost shut but I recovered faster. Since then I have noticed that my rosacea has improved as well as my skin (liver spots fading). I would love to know if others have experienced this inflammatory response after fasting. I have metabolic syndrome, fatty liver, insulin resistance, etc., etc.

Very grateful for Dr. Phinney’s persistence in presenting the science around fasting so we can eat and fast in an informed way to increase our health. Thank goodness for grumpy old men!

There is no reason not to take minerals while you are fasting. Put some salt in you water. Supplement with magnesium. That doesn't break your fast. Be sure you eat a lot of potassium rich foods before you start. And there is no reason to fast for more than three days, since you will get a nice boost in autophagy during that time.

He's comparing apples and watermelons. Fasting lean athletes and fat couch potatoes are two very different things.

I grew up poor, I fasted often because there was no food. Besides keeping a lean figure I can't think of anything harmful from it. If this guy is right my mobilising of food stuff should be zero... However I'm built like a Mac Truck not at all soft and gushy....

Just finished my 3rd five-day fast per Dr. Longo's recommendation (as seen in his video interviews), though I don't bother with his Prolon stuff. Each time I come back to the gym from my fasts I am only 1 or 2 repetitions weaker. I don't know exactly what to attribute that to ... could be muscle glycogen depletion, but I always give myself 1.5 days eating before I return to the gym, so I think my muscles have some glycogen. In any case, fasting 5 days doesn't seem to do much of anything to my muscles. I expect any protein my body turns to during a fast is from my skin, which needs shrinking to accommodate fat loss, and doesn't help me survive as muscle would in a time of scarcity.

I wonder if this video was truncated.... Because it looks like it is very confusing what message it tries to convey? Who fasts 28 days? Or weeks... How's intermittent fasting can be of any relevent to the studies shown that were made on starvation patterns, this video title is confusing and prpbably wrong, it should state the metabolic effects of starvation or extremely prolonged fasting!

Interesting , good to hear both sides ,

I have a question to Dr Phinney. While on a ketogenic diet, is it beneficial to be on a 18/6 intermittent fasting as well everyday (skipping breakfast and having lunch an dinner everyday)? or does it have any disadvantages?

I'm on a Keto, 24h dry fast every day, OMAD. Feel great, lots of energy, mental focus, skin is so smooth and healthy. I recommend it.

I'm fasting now, and my goal is to reduce my BMR so that I don't have to eat so many goddamn calories to grow muscle. So, I should continue total fasting, and avoid eating any protein at all (5:15). High metabolism is just faster death, after all. Why would anyone think a fast metabolism is good? (Because they mistakenly think you'll stay lean with a high metabolism.)

MORAL OF THE STORY: fast responsibly.

very interesting... big help

Would weight training during fasting prevent this? Also as it is easier to carry the lighter body around and thus less muscle needed?

I was doing 24 hr fast from 190 till I got to 155 , and had lost all my muscle. Mostly due to too much excercise during these fast, going to re attempt with less cardio n more weight lifting.

i am not calorie restricting. i am fasting 16:8 and eating until full in an 8 hour window. HFLC

The gut on that guy.

Most of this data has to do with caloric restriction, not fasting.

Maybe naive questions, but: is it possible that "normal" BMR is not ideal and not representative of most of human evolution. And how does BMR relate to aging? Probably also important to separate out fasting regimes where people are eating normal crap that many Americans eat vs a good diet, or at least a pre-1970s diet.

Much respect to the grumpy old intern,great information,thank you.

Why does the body go for vital lean tissue and organs when there is plenty of junk protein in the most of us? Saggy skin, excess skin etc? Do we really want to keep that? How does this fit with evolution. Our ancestors who missed a meal fell to the ground like fat-blobs without muscle? : )

Started on 12/10/20 OMAD diet. I ate only four dinners, 2 of those meals were elk, one was pork and the last was two Christmass dinners which consisted of turkey, ham, mashed potatoes, stuffing greens and whole wheat bread and butter.

Does anyone have insight into HDL particle size, determinants, significance? What if particle size is small, can that be offset by Apo A levels? (size/number for efflux) there are conflicting study results on particle size and potential negative effects, anyone can shed clarity?

Thankyou x

Thx !!!

Dr Phinney is swimming against the stream on this one. Lots of good new science in favor of fasting. I'd love to see a real debate.

What does he mean by fasting for 30 days? Is that for 30 days continuously?

Does the mettabolic rate drop because of fasting or because of losing weight and having less to maintain?

I stopped fasting and started 3 small meals a day. I was just crashing without food, blood sugar was too low and I felt so tired and muscles were just burned feeling.

All the points Phinney is making is true for people who are not LC/Keto. So 99% of the people. But presenting such info one the LowCarb DownUnder Conference without the hint, that it could be totally different for a person, who lives LC/Keto is "strange". And even stranger is the fact, that Phinney does not reflect such most obvious flaws. Mike Mutzel said in one of his latest talks, that this year there will be studies available, which show exaktly that is it a big difference if you are "keto" or a normal person on the SAD. I am looking forward to it!

There's an important thing to keep in mind. (not that it's the whole story) it's natural for your metabolic rate to drop as you lose weight. Someone who is obese by default has a very high metabolic rate compared to a thinner person. So it's expected for the metabolic rate to drop as the subject loses weight. I'm not sure how the metabolic rate changes in people who lose weight in comparison to people who lose weight BY fasting.

A brilliant talk. As always. Glad I did biomedical sciences at uni so at least I'm able to appreciate the excellent science behind this. Slightly disturbed metabolism not discussed this way at uni. It's clear that current guidelines and advice is based on mis-interpretation of the physiology and biochemistry behind metabolism. It's making a lot of people extremely ill as a result. Hopefully the message will catch on and get out there in the end. I perceive a major blocker is gaining acceptance of correct scientific interpretation from authorities because it requires massive changes to the current very established processes and regimes. I take solace that the strain of paying for medical prescriptions will eventually provide the pressure to change approach. Treatment consisting of low carb diet is a cost effective option.

After 10 days on a water only fast I started to get pain in my hips, lower back and sciatic. During the day it was no problem but this pain would seem to intensify at night when I laid down and I was unable to sleep at all the last two nights. I have stopped the fast until I can understand this more. Does Dr. Phinney or anyone else know what causes this and possible remedies? I was doing great other than this. After a post fast broth and fresh vegetable juice regimen I fully recovered in 3 days.

Since you only get one vote here to show if you agree or disagree with the message, then I down voted. There is way too much inter-mixture of fasting protocols, and it STILL really does not answer the question: AFTER a person is on the ketogenic diet for three weeks, or preferably six to eight weeks and has become "keto-adapted," THEN I want to know what happens when a person attempts an extended fast with adequate electrolyte supplementation. If extended fasting can be successfully done for 382 days by a 27 year old man going from 456 to 180 pounds, then the danger seems to be more from a possible lack of knowledge and access to medical support rather than other issues. It is time to get Kevin Hall and NIH to step in and do another study.

There are no words to describe how much I rely on Dr. Phinney and his studies. Excellent presentation.

Dear Dr. Phinney, Thanks for your, as always, informative presentation. You pointed out most of the risk for fasting. However, if you do medical controlled (health fasting) in authorized locations in Germany, the US or Russia, that is not problem. All your concerns are addressed by given supplements or soup, controlled re-feeding is also done. In general nobody advises to make total fasting longer than 5 days without medical supervision. Thus ppl who do that are either professionals which control these factors anyway or have done long term fasting on a regular basis and got used to it. The only thing what is important to follow up, is the BMR. That would be interesting whether if it stays low or recovers slow and what the impact on or life or performance is. Personally I do no longer fast as 5 days on my own. I got use to it (I am also low carb and most of the time ketogenic) and have not problems to gain back my performance in the gym. So from that I feel great even of my BMR is lower now. So pls keep us informed about this topic. Regards Olaf from Germany

Is this metabolic damage (8:00) caused by the fast or is the body just trying to get back to it's previous setpoint of fat% and/or BMI? This setpoint being set by previous lifestyle and genetic factors so that this point will now be pretty much permanent for the rest of their lives.

This is a really well done and tempered seminar. That said, I would dispute some things. The primary one is: "Permanent metabolic damage" is not something I believe exists. There are many of us who have gained and lost 20 pounds over several cycles - many of us who have fastest for a very long time, dropped our metabolic rate, and yet it always recovers. I have over 8 years of spreadsheet data using myself as a science subject and without fail, metabolism will bounce back. I would argue that it is directly proportional to how it was lost. You use the biggest loser data, but I would argue that data is not precise at all. Trying to figure out the LBM, even with DEXA on those super obese people has a wide margin of error. The loss of fat is intrinsically linked to the loss of mass and connective tissue (all lean mass) which supported the fat. All the literature I have read seems to indicate that in a trained individual, there is about a 1:4 ratio of lost lean tissue to adipose in an optimal weight loss environment, and the ratio can be as bad as 1:2 if done carelessly. But the body has many protection mechanisms, especially for rebounds. Most people tout the increase in growth hormone at the end of the fast. Common sense people: The body needs to rebuild what was lost. If you believe the hysteria, they would have you believe that losing fat and gaining fat back will make you weaker and fatter each successive time. If you do some resistance training and some cardio, what you gain back what you lost. This concept of "permanent metabolic damage" is idiocy and defies common sense. The real issue here is how do you stop this yo-yo effect? It is a zero sum game. I'd propose the solution is what we have been saying for years: Change. You must permanently change your habits to permanently change your body composition. If you revert, your will go back to how you were... Not worse, not better. Just... more the same. There is obviously a lot of nuance involved here, and of course, if you have a disease or a genetic defect, you will be an outlier... People need to start respecting the human body and approach these topics from a common sense viewpoint. The science on the human body isn't nearly as precise as everyone pretends it is. This lack of precision makes common sense more valuable than any study which lacks precision. To be fair, it isn't that the science itself is failing us, it is that we simply have too many uncontrollable variables that it is impossible to isolate with the necessary precision to make some of the sweeping statements that are made in scientific studies on human metabolism. Keto is not perfect. Fasting is not perfect. These things are "tools" to use. The body can adapt and thrive in so many different environments and this seminar is a perfect example that every action has a reaction. There are downsides to everything and I am glad he brings this up. But ultimately: Does it work for you? If it is working for you, who cares what the science says? If you feel healthy, and are more healthy, then it doesn't matter if science says you shouldn't be thriving. Let your personal results dictate how you approach. Always be willing to learn and try new things and adjust as necessary.

This is the amazing Steve Phinney PHD. Required watching for anyone who is interested in metabolic dysfunction and how to heal and even reverse this. I've learnt so much from him and his cohort. #LCHF

I am doing one meal per day. Low carbs (30 to 100 gram per day). I am in my late 60's. Weight loss has been slow but steady. I feel well as far as energy is concerned. At my age, you need to be patient, but fasting for a day or so does work. What does NOT work is one meal a day WITH OUT curbing your carbs. No weight loss.

Well, I'm sure Dr. Fung or Dr. Valter Longo will have a retort to this. Interesting stuff. I've done a 72 hour fast and not had any problem physiologically other than extreme hunger. I'm very active and lean and I didn't lose any strength or muscle from the fast. I actually felt great but then I didn't exercise much during the fast.

I started with Ketogenic diet and then once in nutritional ketosis moved to intermittent fasting 16/8 and then moved to OMAD which is 24hr fasting ans the results are much much faster once moved to OMAD. I understand that Dr. Phinney is talking about long and prolonged fasting is not advisable. Correct? OMAD should be alright then?

Check out the MATADOR study. Two weeks is when your body starts reducing metabolic rate. Just be sure not to fast for more than two weeks. If u are intermittent fasting take a break around every 4 weeks.

Fasting, a double edged sword? Please do tell me what the down side is, because I only reap benefits from it. It’s literally the only thing that brings my inflammation down by 100%. Just afraid to go prolonged, but I’m sure if I do... I’d cure whatever that’s been bugging me for 8 months.

So much for this info. I was doing modified keto and recently started adding intermittent fasting. My labs just showed that my potassium and sodium are now slightly HIGH, not LOW. All the videos on RU-vid make it sound like keto and fasting are completely healthy, but they obviously aren’t when they throw your electrolytes out of balance. 🙄

So, but does fasting induce this lean tissue loss? Or do we normally always have this 3/4 pound protein turnover? Because I don't know anyone who eats this much protein in their macros. So wouldn't such a high turnover make us muscle less in the long run? And also, if I go on a diet, why is only around 120g of protein recommended? For example in PSMF, why not 340g ? Hope someone can answer

why would someone want to fast longer than 5+- days or do 5+- days very frequently?

This video just emphasised the need to define fasting vs starvation. Short term fasting has beneficial outcomes similar to LCHF.

In fact Bears are know for their letargy and lack of energy; reason why you can come up to any grown bear which has fasted many winters and just pet them... They aught to be low energy and slow and so even if they were agressive then you could just slap them back into submission, you often feeding human you! (Works with crocodiles and mice too, just starve them and then come up and pet them)

Anyone who is fasting for therapeutic reasons and not just weight loss has probably found that one doesn't do an extended fast and then start pigging out immediately after beginning to eat again. That's just common sense. People who have been starved in concentration camps where it wasn't their choice would have probably had a different opinion once they were allowed to eat at some point, and that is understandable, but the therapeutic faster is not in that same category.

Title says fasting, nowhere in the video was anyone fasting.

A good caution about the symptoms of refeed syndrome, especially since breaking a fast with a heavy resistance training session followed by the refeed is a popular method of harvesting the significant anabolic effect of the refeed. I think the syndrome is more likely after an extensive multi-day fast especially if not previously fat adapted. I have not noticed any of the symptoms after three day fasts but it might behoove me to get a blood panel done directly after just to verify no aberrations (particularly the hypo-phosphate condition). Edit: The BMJ study from the 18:15 slide is fascinating and is available on line: www.ncbi.nlm.nih.gov/pmc/articles/PMC2440847/ Oh, and that study says the syndrome is most likely after fasts of more than 5 days so I guess I am OK then. Fasts of longer than that have very diminishing returns anyway.

lmao i couldn't do even 15kg on bech when i was 80kg now I'm 69 kg and i can do pull ups, 100kg on deadlift, 60 kg on bench and have no inflammation what so ever and all my problems have been solved. I've been fasting since February.

Well, only the true fasting lunatics do 28 day fasts...though it was interesting to see the data indicating potential permanent damage to metabolism from doing such fasts. Most of 'us' do time-restricted feeding with the occasional longer (1 to 5) day fasts thrown in for cleansing, and the associated anti-ageing benefits [I personally have ever only done a 5 day'er employing the 'Longo' fasting-mimetic diet, and found no bad after effects. Though, I did notice a prolonged exercise weakness from doing a 3 day pure water fast...which was somewhat disconcerting]. As for not taking in (natural) salt and various supplemental minerals during a more extended fast...well, you have to be devoid of basic common sense to not do so.

As always, Dr. Stephen Phinney does an excellent presentation here. Thank you for uploading this. I am a huge proponent of intermittent fasting, and I have alternated between the 16/8 and OMAD fasting strategy, in conjunction with a low carb diet, to lose 98 lbs - going from an obese 230 lbs to a pretty slender 132 lbs. So I can't sing the praises of low carb and intermittent fasting enough. I have contemplated longer fasts, to further augment the health benefits of fasting, but have never actually tried to do that. Dr. Phinney's counterpoint to long term fasting does give me pause. It would be nice to see a debate between Dr. Jason Fung, arguably one of the most widely known proponents of longer term fasts within the low carb community, and Dr. Phinney.

For fasting more than a few days, ensure you're taking 3,000 to 5,000 mg of sodium, 4700 mg potassium (potassium chloride or citrate), and 4000 mg magnesium malate

Dear Dr. Stephen Phinney , I would like to ask a question! I've read the study about refeeding syndrome and i understood that it happens after an increased insulin and decreased secretion of glucagon. If my refeeding is based on a ketogenic diet, should i be afraid during refeeding after a prolonged fast?

Phinney may not be bankrolled by anyone but I know MIT is. I do IF everyday for 18-21 hours. Works fine for me. Westman and Fung among many others would have a different take on this. I like all of them but the only real research that is important to me is the research I have done on myself. I still enjoy learning something every chance I get but don't take it to the bank until I have tested it on myself.

I totally did not get what you were saying.. I’m just a normal person.. but are you saying that intermittent fasting.. like every day for at least 18 hrs every day forever will hurt a person????

does anyone know an appropriate amount of potassium to take with the supplementation (as potassium carbonate plus ascorbic or citric acid)?

Thx Doc.... I learned a lot but one thing you forgot about the studies made... Genetics, Lifestyle of people, Resources available... i'll stick with my Keto and IF as I benefit a lot

Why can't I see the comments?

You can’t equate results from caloric restriction diets and fasting, and you can’t expect the same results from fasting on a carb based diet vs keto based diet. The people from biggest loser and other diets that focus on extreme caloric deficit never allow their bodies to get into full ketosis because they’re still carb based. This results in way more tissue breakdown for gluconeogenesis which obviously would trigger decreased metabolism. None of his data mentions prolonged fasting in a ketoadapted individuals, which are less likely to undergo gluconeogenesis. I understand the importance of knowing the potential dangers of diets, but any diet can be dangerous if done improperly.

Fasting might cause loss of heart tissue? Is that true?

I wanted to thank you for sharing the dangers of fasting. I also acknowledge your statement and belief that fasting can be very beneficial. I haven't heard much on the dangers and your information on this perspective has been very valuable. While those who have been studied while fasting showed no drop in potassium, I did suffer a drop in potassium and magnesium and suffered with refeeding syndrome. Thanks to your bravery in presenting the downsides and cautions of fasting I am now fasting only to 40-48 hrs and taking supplements and eating high quality foods on break days. My weight is now falling off at moderate rate and I am full of energy and not feeling sluggish as I did on longer fasts. I am in a constant state of ketosis and my glucose remains in the low 70's to 80's range. I am eating to satiety yet jotting down what I eat so I can make note of my caloric data. Thank you again.

I have been fast for Autophagy for the last 2 years, up to 4 days And once or twice a month but 2 days is the most common. Problem is re-feeding is my problem, when I manage that correctly I’ll be a super power guy.

I'm confused.. So fasting is bad for long term weight loss/control?

Agree with all the comments on Dr Phinney.... See Dr Alan Goldhammer’s video on fasting.

well he asserts that whe reduction of bmr by caloric restriction and the reduction of bmr by fasting is the same, go look at angus barbieri's fast and youll see this is a wrong assertion, about the electrolytes argument, drink salt water (snake juice lol), if anybody says go on plain water for 30 days hes asking for dehydration. about the hypoglycemia, first of all most of the diabetic patients suffer from hyperglycemia so it actually shows that it is a very strong natural way of treating the disease, and it wasnt intermittent fasting but rather the 5-2 methods which isnt a real fast, those are two different things, the fact that in the conclusion it says any type of fasting doesn't make it true. relative risk is not absolute which i do wonder what it is. the supervision in the refeed window is something i accept and i do think the worst way to break a prolonged fast is with a lot of sugars but as u agreed it has its benefits. about the protein, of course that on a very long term fast you will lose lean body mass, the problem i have is that there are obese people that can still benefit from fasting despite that reduction and you scare them, i bet angus wouldn't have gotten to 96 without that fast, and it doesn't show the anabolic effects of the refeeding if they exist which i assume they do because if they didn't then that would create a hole in evolution since there were times we had to fast, so we were catabolic on the fast but if we werent more anabolic after a long fast then people would have simply lost most of their muscle without gaining it back back in the paleolithic era and natural selection would have kicked us out already. again this is a speculation but i do think that there is a high possibility that this mechanism does exist.

when does Jim wrestle the alligator?

This is great. I just cant picture how people manage to go Omad and eat enough calories. I tried and still couldnt eat more than the usual meal and had to go back to normal keto because I started gaining weight. Maybe it's something cultural, rations are much smaller in europe and I cant picture someone reaching some daily macros in just one meal.

16:00-16:16...I think this debate boils down to what he said there. If the issue is that fasting depletes your minerals, then replenish them after your fast. I've read many studies on how fasting forces the body to "eat away" our toxins because it can't get it's fuel source from food during that time...so, in my opinion, that out weights temporarily losing some minerals during the fast. Plus, I've read you should take some sea salt with water during your fast to diminish losing too much sodium. Anyway, there are some dangers to fasting if you have a lot of health issues and it's done without guidance, done wrong or for too long but we can't fully deny that fasting does have a lot of healing benefits too. And speaking from experience on the positive of fasting...I got out of diabetic range doing 'clean Keto' AND intermittent fasting. And it wasn't until I incorporated intermittent fasting that it really speeded up my progress.

I just did a fair amount of hiking and ate the calories that I suspected would be necessary at ideal weight without exercise. So here I am, weight off, and eating well all along. I’ve done a 7 day water fast some years ago. An 8 hour window is now enough for me now. And of course, I don’t eat if I’m not hungry. Nothing special.

I may have missed it, but I suspect the individuals were not on a low carb or fasting-mimicking diet which really affects the results. I still appreciate the alternative information 👍 Also, everyone I know that fasts emphasizes the importance of electrolyte supplementation

So many terms used in this discussion are either not defined or badly defined. Even the word, "fasting" can have a number of different meanings. Some of Dr. Longo's research even suggests that a diet that "mimics" fasting, meaning (I think) one gains the metabolic benefits of Fasting while also eating certain foods, triggers MORE or STRONGER fasting-related benefits. Does this mean if I drink bulletproof coffee while fasting, which has at least 100+ calories from MCT oil and butter, I'm no longer fasting even though my body is still metabolically acting like I am? If autophagy is still occurring in spite of my calorie consumption, is it still a fast? What we are trying to achieve is the maximum benefits of fasting in the best way possible. Should we discover eating certain nutrients does that, the choice to me seems obvious. We'll just need a new word for it.

Scary stuff.

So then......what is the answer?

My sister has been doing intermittent fasting for more than a year now and the same with me. Everything is in normal range a1c is perfect 5 mmol l. My clients are doing the same and none of your issues ever come into play. Intermittent fast is not jus every two days. IF is in various forms. I suggest you look into it. IF has shown so much positive results and I believe your position is a bit off the chart.

Permanent metabolic damage... a loss of 20% of 2000 cals used per day is 400. About a bar of chocolate or 40 minutes of light jogging.

Interesting having come off a 5 and half day fast

Ok so ill keep adding pink salt and cream of tartar to my water and fast withour fear of death. As a type 2 diabetic my bloodsugar as never dropped lower than 150. Even after a 5 day water fast. Omgoodnes my liver must be very fatty!