Are you changing your long term fasting length after listening to the Phinney interview?

(Bob M) #1

So the 2 (actually 3) keto “dudes” interviewed Dr. Phinney at the last ketofest:

Dr. Phinney is still against fasts lasting longer than 3 days, as he says you being losing muscle mass. I normally fast about 4.5 days, so I don’t think I’m going to change that, as it seems to be not too much past 3 days. (And I don’t know what 3 days means…If you eat Sunday night then fast to Thursday morning, is that 3 days or 3.5 days; I’d call it the latter.)

Do you think you’ll change your length of fasting based on Dr. Phinney’s comments?

(PJ) #2

I hesitated to put my superfast transcript notes just from the fasting part here since of course this is the 2KD forum and we want people to listen to their show. But I listened and it wasn’t until the end it came on. There were a few words/names I didn’t recognize (in parens).

This is very interesting stuff. @Karim_Wassef you might find it so.

Phinney podcast with 2KD posted 29Jul2019

  • fasting - are you and fasting people coming to some consensus?

I’m a student of history… including published data… pub data on safety of long term… intermittant fasting no problem… more than 2-3 days … there are concerns in terms of preservation of lean body mass, and providing adequate mineral (and nutrient?) … cause if you’re doing a total fast, a water fast, your body is still excreting minerals, but you’re not taking 'em in… and if people are living on a margin, particularly around the central minerals, I won’t get into sodium, but potassium and magnesium are minerals that we have to deal with actively in many of our patients, and if part of the time they’re not getting any of it in, that means we have to do even better on the days when they ARE taking in nutrient dense food.

  • so what about fasting with electrolytes then?

but then there’s still the loss of lean body mass … you know, people deny that it’s important, they call it autophagy, and there is animal data and some human data that says that’s important, but I’ve not seen any data that says that if you’re – let’s say you’re following a ketogenic diet, THEN you add a fast, that you get benefits from this process, that people call autophagy, because we know that ketones are a clean-burning fuel, and they preserve mitochondrial function better than if you’re not in nutritional ketosis. And that’s really what you’re trying to achieve with autophagy, and you may have already gotten there. So adding it in, I’m not convinced is beneficial. So I want to see published data in peer reviewed journals. I mean we’ve made that commitment, and I’m not throwing out a challenge, I’m just saying if you’re evaluating for yourself what has proven beneficial, I would look at what’s published in the peer reviewed literature. Realizing that it is very hard to get countervailing data like ours and their published, but we have to do that.

  • we had to get fasting studies published through an (IRB??) so it’s almost impossible to get a starvation study – we couldn’t repeat, we probably couldn’t repeat the starvation studies George Cahill’s starvation studies now I don’t think, because of that, we couldn’t probably, we couldn’t do it with animals, I could be wrong –

I think that that, I would say that’s probably would not be the case for durations of one to two weeks. Bruce Bistrian published a paper in 1977 where he had people on a weight loss ketogenic diet and for two weeks – three weeks – and looked at how their bodies responded in terms of giving them adequate protein, and even in the first week of a protein-supplemented modified fast, which is under 800 calories a day but enough protein – for the first week they were losing lean tissue even though they were eating the protein and minerals. The second week they were coming almost up to zero. By the end of the third week they were up to zero, then even though they were eating under 1000 calories a day they were preserving lean body mass. And that was radical data back in the late 1970s. But then he – they were already three weeks into the adaptation process and then he had them do a one week fast. Now this is on – in a metabolic research ward under observation – and they immediately dropped down to losing something in the range of 1/3 to 1/2 a pound of lean tissue per day. And then that week they were showing they were beginning to re-adapt, at that. But there’s – I don’t know of any evidence that says that in terms of lean body mass preservation, that any form of fasting beyond a couple days is benign in terms of that.

  • so is this subject to the adiposity of the subject? So (…) bodyfat can deliver so much energy per day, are we talking about energy insufficiency during a fast? Some people have enough energy on their body that they’re not gonna be energy insufficient in a fast.

You would hope that’s true. And it works in hibernating bears. People’ve actually done studies – and bears they don’t hibernate they sleep in their dens, but people have climbed in the dens of wild bears as they’re sleeping and drawn blood samples on them and then hustled their butts out of there really quickly – but they’ve looked at the ability – and bears can preserve lean tissue by running just on fat. Humans cannot do that. And fat mass does not protect us from protein catabolism. We can reduce it down to, after a month of total starvation, losing just a quarter pound of lean tissue a day. But we’re still losing that. And so again, this is not completely theoretical, because the other risk of prolonged fasting is that depending on how you end your fast, there is a potential of having acute shifts of fluid and minerals into cells, which can lead to abnormal heart rythyms and sudden death. And that was reported in multiple situations during WWII when people were subjected to prolonged privation in lifeboats or in concentration camps or something, we killed people with kindness by giving them lots of food. You have to introduce the food slowly. And just telling someone, well don’t binge when you come off this, is I think not adequate in terms of safety.

Well I think

46:50 downloaded audio file lost audio (continued playing just no audio)
Went to online original. He ended the interview there anyway. :slight_smile:

Fixing Broken Metabolism - Dr. Berg
(Bob M) #3

Thanks for that. That’s a great transcript.

This is what I was thinking of. The electrolytes, I’m not too concerned with, as I drink pickle juice, take in salt, and next time might take in extra Mg and K.

The problem is that 3+ days is when long term fasting gets “good”. The second day is usually the worst, and it usually gets better from there. And you want enough days to cause autophagy (whatever this is - Dr. Phinney seemed to imply it was deleterious) and insulin to drop low. I can’t make it through a weekend, so I usually fast 4.5 days, from Sunday to Friday sometime. And as for losing muscle mass, for the number of times I fast a year like this, 4 at most, I can’t see that being a big problem.

(Todd Allen) #4

No. I’ve stopped making dietary decisions based on other people’s opinions even those I highly respect such as Dr. Phinney. Instead I go based on results. It’s not that difficult to track physical performance and body composition and to evaluate the impact of longer fasts. And when I don’t get a measurable difference it probably doesn’t matter that much.

(Robert C) #5

Changing fasting after listening to Phinney?
If someone can fast for over a year - there might not be much of a concern about muscle loss starting after 3 days (which would kill you much sooner if it continued).

I think what might be important is the diet you are coming from and that there might be three phases to fasting.

I have no science to back any of what I am writing - just intuition…

  1. In the initial phase (first 2 or 3 days for most people), if you are a SAD/glucose burner then suddenly start fasting, it might make your body cannibalize muscle if it can get that easier than using stored fat (because of insulin resistance). But, if you are fat adapted, I would imagine that burning fat instead would happen (or at least help avoid the body going after muscle).
  2. In the second phase, fasting adaptations happen and specifically growth hormone increases as a protective effect (i.e. muscle preserving effect).
  3. In the third phase, refeeding, there is still growth hormone present and most/all/more muscle is regained (especially with some exercise and good refeed foods).

Phinney works with already-at-goal heavily muscled athletes where fasting might not be appropriate. But, Dr. Fung works with people that have 100 pounds or more to lose and their timeline is very short (as they might be trying to avoid organ failure). It might simply be too long of a time to wait for a “well formulated Ketogenic diet” to work to lose very large amounts of weight. Getting Keto right is, for some, difficult. Getting fasting right is very easy - there are no decisions about how to hit macros (as they are all zero grams).

(John) #6

No changes for me, but then I only intentionally fast infrequently (about once a month) and usually for a duration of 30 to 48 hours.

So what I am already doing is within what Phinney doesn’t seem concerned with. I have done a couple of longer fasts (60-ish hours) and find I don’t really feel quite right that 3rd day. The shorter fasts accomplish what I need - re-calibrating my response to eating signals, which is more of a psychological rather than physiological thing for me.

(Bob M) #7

I find tracking a 4.5 day fast to be very difficult. My weight will plunge the first day, level off, then immediately come up after I eat, often meeting or exceeding where I was before. (Overall, I keep losing weight, but an individual fast might not do much.) I also had calf spasms the last one I did, which means I’m not getting enough of something, though it’s difficult to tell what.

And I’ve never given myself a DEXA scan before and after. Maybe I am losing muscle? And even if I did lose muscle, what would this mean? Maybe this is really muscle I could afford to lose?

I also have found that when I was 30+ pounds heavier, I could easily do a 4.5 day fast, and even exercise a few times during that period. Now, 30+ pounds lighter (and 60+ pounds overall, with more muscle), I don’t even attempt to exercise during a 4.5 day fast. Maybe I’m getting closer to the type of person Phinney is considering?

(Todd Allen) #8

Yes there can be a lot of short term variations but they smooth out on longer time frames. I’ve had pretty good success trialing things for a few months at a time. I get dexa between each period and track weekly with tape measure, skin fold calipers and a scale and track physical performance daily.

There are disruptions such as injuries, colds and other big events and changes which confuse things but they haven’t been frequent or severe enough to make me lose confidence in the process.

(Old Baconian) #9

Note that even Dr. Fung and Megan Ramos don’t advise fasting for more than a few days at a time, except under medical supervision.

Bear in mind that the outlier case everyone likes to refer to, Angus Barbieri, had made a commitment to his physicians that he would show up for regular monitoring, take supplements as needed, and stop fasting the moment his physicians felt he was harming himself.


My main reason for fasting is cancer prevention (both my parents died from cancer in their 50s).
I also love the weight loss.

Should I lose som muscle, it’s still worth it.

(Central Florida Bob ) #11

The problem I have with this statement is that people jump to the conclusion this is muscle loss, and especially skeletal muscle. There’s a lot of lean tissue in our bodies and skeletal muscle is just one part of it. Our bodies are loaded with connective tissue - membranes and thin structures as well as tendons, ligaments and more obvious connectors. Without the mesentery, for example, our organs would slosh together when we stand up! Part of the lean tissue is extra skin many of us would like to be rid of. We want to lose lean tissue.

I have one of those Renpho body composition scales. It tells me, for example, I have 143 pounds of muscle mass but only half of that (48.5 %) of that is skeletal muscle - the kind that weight lifting and body building emphasize. The other half of that is muscles lining the digestive tract and stuff you’d never think of. Yet when people see loss of lean tissue they immediately jump to assuming it’s skeletal muscle.

So when Dr. Phinney (whom I admire greatly) says after a 3 day fast people lose lean tissue, I don’t know that’s a bad thing. I personally want to lose some of that lean tissue. If I can get rid of some sagging skin by fasting that sure beats buying surgery and the risks that come with that.

(Bob M) #12

That was my issue too. Without more data, it’s impossible to say what this means. And for someone like me, who does a 4.5 day fast at most 4 times a year, it’s probably not a big deal.

(PJ) #13

I agree, @ctviggen and @CFLBob (Bob and Bob!)

I won’t bore you with my medical history to explain why, but suffice to say I have some unusual experience with being able to very clearly feel the “fibrous tissue” that protein-edema grew for me to support the massive weight of the fluid, and that I believe grows to provide an infrastructure to support adipose tissue as well. I feel pretty sure that there is a LOT of “tissue mass” that is lost along with fat and its associated edema. Maybe it counts as lean body mass – but it’s not like losing a part of your liver or your thigh muscle.

I think this lack of ability to clearly delineate this detail is rather messing up assumptions about autophagy.


(PJ) #14

To that point:

Adipose tissue, commonly called “fat”, is a type of loose connective tissue comprised of lipid-filled cells (adipocytes) surrounded by a matrix of collagen fibers, blood vessels, fibroblasts, and immune cells … WAT represents the vast majority of adipose tissue in the organism. … WAT is composed of many cell types, adipocyte being the most abundant. The other cells, collectively referred to as the stromalvascular fraction (SVF), are a heterogeneous population of endothelial cells, macrophages, fibroblasts, stem cells, and lymphocytes.

(Central Florida Bob ) #15

Absolutely! If one loses fat, they don’t need all that “infrastructure” to support fat that isn’t there any longer. Losing that is losing lean tissue and that’s exactly what we want to happen.

(Old Baconian) #16

Just bear in mind that we don’t get rid of fat cells when we lose fat. What we get rid of is the contents of fat cells. Fat cells get cleared away when they die, just as other body cells do, but not simply because they are empty. So that matrix of collagen, etc., isn’t necessarily up for grabs any time soon. On the other hand, if you’ve lost quite a bit of fat, then losing some of the muscle that you no longer need for hoisting around all that fat might not be as unhealthy as it sounds.

But anyone interested in fasting should also bear in that the figures about protein loss being bandied around come from studies by Cahill that have never been refuted. “Starvation in Man” makes for some highly interesting reading, and you’d think that if Cahill had gotten it wrong, somebody would have published a refuation by now.

(54 yo female started keto Jul '19) #17

In one of the 2ketodudes podcasts @richard mentions a time frame for the life span of fat cells. I don’t remember how many years it is, but I remember it was long. Like 5 or 10 years or so?

(Central Florida Bob ) #18

How relevant is “Starvation in Man” to short term fasting? I don’t think anyone disputes that if people get zero food they eventually die. It’s the dangers of short term deprivation of food that’s the topic. My point is that saying there’s “lean tissue loss” at 2-3 days doesn’t distinguish exactly what you’re losing and maybe losing it isn’t a bad thing.

In general, people hold the very common falsehood that “if a little is good, a lot must be better”, and that can be dangerous. Consider your micronutrients, which include things like selenium and manganese. Both are toxic if you get too much. I think everyone agrees that fasting is the same way: a little is good, too much can kill you.

(BuckRimfire) #19

I can’t remember that episode precisely, but, yes, I think your 5 or 10 year timeframe sounds like what he said.

Too bad there’s not a searchable transcript. I suppose it would be possible to run all the podcasts through voice-recognition software and get a moderately accurate output. Although, all the crucial technical words like “adipocyte” would be horribly munged to something like “at little site,” so on second thought, it probably would be almost worthess.

(54 yo female started keto Jul '19) #20

I didn’t find the podcast, but I did find the information: each year about 10% of the fat cells is renewed:

Back on topic: I also am not worried about some shedding of ‘lean mass’ and did not change my fasting regimen.