The backlash on fasting stems from the “protein priority” nuts out there who keep banging on that you need a crap ton of protein per day…like 100 -150 gr, or your muscles will waste away (such nonsense). It’s not possible to eat that much if you fast. For me it isn’t even possible (or desirable) when I don’t fast.
Does this study on fasting show that fasting doesn't work?
OldDoug
(Doug)
#42
A late reply here - some of the stuff at Virta does not sound like it comes from Dr. Phinney himself; my opinion - it’s just too obviously incorrect. (We’ve had discussions about it on this forum before.) There are (or were) some really rudimentary and brutal errors, like claims about how much protein/lean mass is lost during fasting for multiple days. The first day or two is one thing, and it falls off a cliff after that - down to ~ 15 or 20 grams per day (from memory) - and this has been known since the 1960s/George Cahill’s research, etc. Virta had it continuing at the initial pace, which is just silly.
If we’re losing 20 grams of protein per day, it takes 23 days to lose 1 lb or 50 days to lose 1 kg of it.
As I recall, Richard - one of the two Ketodudes and founders of this site - actually gained lean mass on a fast. Now, that sounds like impossible magic, and it may be due to vagaries in Dexa scan reporting rather than reality, but it points up how limited true desirable lean mass loss usually is, especially ‘lean mass’ per se, versus muscle loss. Autophagy is scavenging and recycling intracellular protein, for one thing, and there is also our skin - roughly 1/6 of our body weight - to use as a source.
As to fasting itself, Phinney has also admitted that he’s prejudiced against it, to an extent. His thing is much more ketogenic eating versus a high-carb diet, again IMO.
I think a lot of the differences between people’s positions on fasting stem from the wide variance among people from the beginning. To generalize - younger, more metabolically healthy, more athletic people want and need different approaches, versus older, glucose-tolerance-impaired, just wanting to lose fat and be healthy people. Rather a Phinney/Volek versus Fung thing (for example).
The amount of protein available to us when we’re fasting is often forgotten, but we’re “eating” our own protein, as well as our own fat. In vitro, autophagy has been recorded at very high rates, again from memory as much as 1% - 4% of cellular mass or cellular protein, per hour (can’t remember which). Obviously, that’s drastic. 
I don’t think the rate within a fasting person is anywhere near that, but it doesn’t need to be.
If we say that a person needs 100 grams of protein per day, then autophagy’s recycling only needs to be ~0.1% of their body weight per day, in rough terms (obviously people weigh different amounts).
Polly1
(Polly)
#43
You make a very good point about autophagy providing a good source of protein when fasting. The arguments that you destroy your own musculature whilst fasting do seem to ignore autophagy and its friend apoptosis which are desirable outcomes of a fast.
PaulL
(Bacon is a many-splendoured thing)
#44
Atuophagy tears down muscle as well as other proteins. Think of it as scavenging—in the middle of a blizzard, when you’ve run out of firewood, you look around the house for anything to keep the fires burning. Scrap wood is the best long-term choice, but sometimes you find yourself chopping up the antique furniture. So what we want is for autophagy to scavenge proteins we can do without, and it usually does, but sometimes, when we need nitrogen, some muscle tissue has to be sacrificed.
Ideally, autophagy works in service to the body’s other repair mechanisms, and the amino acids that autophagy scavenges are use to build new proteins. However, the body needs to use up a certain amount of nitrogen every day, and if autophagy can’t scavenge enough damaged proteins, or enough proteins that have reached the end of their useful life, then it has to get amino acids from somewhere. Breaking down heart muscle or the brain would be a bad strategy, so it’s skeletal muscle that gets used first.
lfod14
#45
So people who prioritize protein are “nuts”? Some of us like having muscle on us, and 100-150g is HARDLY a crap ton! I got huge into fasting and lost a ton of muscle over it which was confirmed with DEXA scans, so what is your basis for the “such nonsense” claim? Because I’m hardly the only one who has had that same end terrible result. How much fasting do you do and what’s been the result of your DEXA’s showing muscle mass holding on?
KetoIFgal
(Joanne)
#46
I’m not a super lean, young, male body builder. I am an old lady with hundreds of thousands of calories of stored energy (aka fat) on my body. I have no fear of losing muscle when I skip a few meals. Yes, I believe the fear mongering around muscle wasting is nonsense.
ctviggen
(Bob M)
#47
Not sure about that. Dr. Fung has said basically no people lose muscle mass on his fasting. Of course, the amount of fasting can be different, as can the goals. Your goals appear to be to get HUUUUUUGE, and I’m sure 99% of people Dr. Fung treats don’t care much about getting muscular.
I also like a lot of protein and low fat. And I think sarcopenia is very dangerous. But I think you’d need protein + exercise. (Though I saw a recent study where just giving dairy to the elderly was associated with fewer bone breaks. That’s both calcium and protein, though.)
My opinion is higher protein is basically always better than lower.
lfod14
#48
That un-smart person who isn’t right as much as he thinks he is (to protect the sensitive at mod request) is the reason I got into it so much, specifically because I believed that I could do it while losing fat and not losing muscle… WRONG! My goals are to be muscular, which now that I stopped fasting and switched to CKD/TKD I’ve re-achieved, not where I want to be, but way better than what I was. Hardly looking to walk across an Olympia stage or even compete at all. I’d like to see the DEXA’s of his patients and how much muscle they had pre/post him and his fasting. I’m willing to bet none of them before or after had enough to matter, meaning just normal.
If he’s going to make blanket statements like “you won’t lose muscle” then he should assume that some people actually have more than is required to move on them. I learned my lesson with him.
AGREED!
robintemplin
(Robin)
#49
This thread is a good example of how words like “nuts” or “morons” can turn a discussion into an argument. I don’t believe anyone here is purposefully or specifically insulting others. There is a HUGE variance of opinions and approaches in the keto community. And we’re lucky to be able to express it here. (Sorry. I’m not your mom. Just an old hippie who wants everyone to eat along.) 
Polly1
(Polly)
#51
@MarkGossage knowing that Jason Fung features in your profile picture- Do you have any thoughts on fasting and muscle loss?
MarkGossage
(bulkbiker)
#52
Never been especially muscular anyway (even after decades of gym going) but don’t think I have lost much if any after years of intermittent and extended fasts… although full disclosure I haven’t done an extended fast for a couple of years.
I am probably older than you tho 
Digital_Dave
#54
See, I noticed that typo thingy too, but didn’t mention it since I actually liked that it read “Eat-Along”, and not “Get-Along”. 
It just has a better feel to it, especially here…
Ok, folks, nothing else to see here… Eat Along. 
:
Fangs
#55
and ya posted a darn burger with a bun! How dare you 
US family gonna have to have a chat with you and set ya straight 
Jamesbrawn007
#58
Some recent research looking at alternate day fasting, as well as KDs, shows some lean tissue loss once energy is restricted. This is exactly what people on conventional energy restricted diets experience.
Fasting has numerous benefits but, similar to arguments around continual ketosis, trying to hold it out as something magical where there can be zero negative outcomes is misguided.
robintemplin
(Robin)
#59
@Digital_Dave @Fangs @Polly1 First, Fangs… doubtful you are older. (67 here) And I did NOT realize my typo. But it’s a great typo, isn’t it? Why can’t we all just eat along? I’m sure I’ll find reason to use that phrase this thanksgiving. 