Could there be such a thing as too much autophagy?


Hi everyone, just wanted to know if any of you are teaming up keto/carnivore with IF and what types of fasts you do? I have both done 20:4, 18:6 but my body I’ve discovered feels most comfortable doing 16:8. I typically eat 2-3 meals a day, though I add in a morning snack of a tiny handful of nuts and a square or two of dark chocolate with my green tea, it’s one of my old habits I refused to give up. I have played with the idea of trying OMAD but I don’t believe I am yet ready for that, though I will be doing it on Christmas day as my partner traditionally always has, I shall try it his way this year, so as to not ruin our appetites for the big Christmas meal :slightly_smiling_face: But anyway, do any if you think there could be such a thing as too much autophagy? I’ve read about countless benefits you may reap from IF, but also about problems and potential cell death, so, as always, there is conflicting information out there. Dr Jason Fung covers the topic well, but I don’t think even he has delved into the possibility if there ever being such a thing as too much autophagy and it actually ending up being harmful instead of beneficial. Again it boils down to reasons for doing it, metabolic health, medical history, etc, but my current belief is that low-level fasting seems beneficial, but that caution should perhaps be adviced when it comes to extended fasts. And I could be entirely wrong. I don’t ever mind being wrong if I end up learning something useful in the end.

(Allie) #2

I would think that as autophagy only happens to old and damaged cells, it would be difficult for it to happen too much, unless there’s another serious issue going on that is causing way too many damaged cells but if that were the case, that would be the biggest problem rather than any effects from autophagy.


Yes I think in a healthy person autophagy is probably very safe. The science gets a lot more complicated in the case of cancer, where they both state autophagy could be beneficial in such a case, but also encourage the growth and spread of cancer cells. I think only in the case of someone having or having had cancer autophagy could become a two-edged sword. But for most, for healthy individuals, the benefits probably far out weigh the risks. I told my mother about IF and now she is doing it and becoming interested in its effects, which is great. I have had cancer in the past so I am not sure where I stand with fasting. I believe for me and people who have been in my situation IF (intermittent fasting) is still beneficial, but I personally would be wary of extended fasts.


Any chance of a link to some of the studies you’ve been reading?


Hi, the latest article I read was this one from ncbi,by%20a%20series%20of%20proteins.

I’ll copy a couple paragraphs: “in cancer cells, autophagy suppresses tumorigenesis by inhibiting cancer-cell survival and inducing cell death, but it also facilitates tumorigenesis by promoting cancer-cell proliferation and tumor growth.”

“In cancer biology, autophagy plays dual roles in tumor promotion and suppression and contributes to cancer-cell development and proliferation.”

Now I don’t know how any of this applies to someone who has had cancer, but is cancer free, such as in my case. I’ve been cancer free for three years now, and am going strong. For most healthy people I don’t believe autophagy could be anything but beneficial, but even then perhaps, too much could potentially cause problems. I’m not an expert, I just don’t think there’s been enough research into it and that more is needed.


Great, thanks - I’ll have a read.

(May the blessing of bacon be always with you) #7

A lot of people combine keto with intermittent fasting or time-restricted eating. On the other hand, it appears that carnivores mostly do not fast, and do not recommend it. Personally, I have issues with fasting, so I usually don’t.

Once you are at the point where you find yourself skipping meals because you forgot to eat, that is a good time to experiment with fasting, to see if it works for you. Don’t force your body into something it’s not ready for.

No, I don’t. It is a tightly-regulated process. The body doesn’t just go scavenging tissues for no reason.

The only time the body might break down needed muscle, say, is when we are in the middle of a famine (this is the nutritional equivalent of burning the furniture because we ran out of firewood). It is the reason we strongly advise against not eating enough food. I suppose you could consider that as “too much autophagy,” come to think of it.

(May the blessing of bacon be always with you) #8

Granted, I’m reading this out of context, but I think it is a misunderstanding. Dr. Thomas Seyfried, a noted oncologist, strongly holds that cancer is the result of metabolic damage from consuming too much glucose (i.e., carbohydrate). Normally a damaged cell shuts down and is scavenged by autophagy, but the wrong kind of damage can encourage proliferation instead of shutdown. I don’t see how autophagy could contribute to that proliferation, but I might be missing something.


I think the article I read and quoted from was referring to the effects of autophagy upon cancer cells when cancer had already struck. I didn’t understand from that that autophagy in itself would cause cancer in a healthy person. My cancer might very well have been caused by metabolic damage as I ate a very high carb, low fat, low sodium diet at the time and also had a chocolate addiction. But according to Dr Fung cancer happens because of long term chronic inflammation which I have also suffered from, and it might be that that too is caused by metabolic damage, from a poor diet. I am also awaiting the result of a coeliac blood test which may or may not throw some light on it, as I had to give up gluten. Anyway, I find it interesting that carnivores feel less inclined to do fasts as ever since I have been cutting down on my carbs, to just about 10 grams now and am eating primarily meat and fish, I have been more hungry, and so I eat whenever the body requests it, but generally tend to stop after 18:00. And that seems to be working swell.

(May the blessing of bacon be always with you) #10

One of the problems is that autophagy doesn’t seem to work on cancer cells, or have I got that wrong? Cells are supposed to die (apoptosis) when they get too old, or if something goes seriously wrong with them. Part of the problem with cancer is that this process goes awry when certain types of damage occur. And it’s a type of damage that prevents the normal mechanisms of the body, such as autophagy, from dealing with it properly.

I guess it’s just more evidence that we didn’t evolve to cope well with a high-carbohydrate diet.

(Laurie) #11

I usually have 2 meals: one at noon and one at 5 pm.

There are two reasons for this, one at each end of the day.

  1. I’m not hungry in the morning.
  2. I try to limit my nighttime eating, because in the evening I tend to eat for pleasure, not hunger.

Sometimes I do eat earlier or later, for example, if my schedule changes or if I didn’t eat enough supper.

I’ve read enough to convince me that daily intermittent fasting is a good idea, and it’s easy (for me), so why not?

I’m not really interested in autophagy at this point, so I don’t know much about it.


I honestly don’t understand the science behind it enough to know why autophagy can cause proliferation of cancer cells. But yes, they are abnormal cells and so the body becomes unable to handle them, kind of like invaders with some unknown, mysterious powers and superior forces. I remember when I was undergoing chemotherapy I perused several articles on autophagy and cancer trying to make a decision whether to fast or not. In the end I ended up eating normally, following more conventional advice, making sure I ate the typically recommended variety of fruits and vegetables, but I gave up sugar, or so I thought. I never knew anything about fructose’s effect upon the liver back then. Anyway, I do believe when the body is given the right building blocks it can rebuild and recover from metabolic damage but how long that will take, well … who can say. But any sign of healing is a whisper from your body that it is doing well.


I think there’s some low-level autophagy going on all the time really, like when we sleep, that’s a fast in itself. And I can’t see anything problematic with time-restricted eating such as the decision not to eat in the evening, as we were never meant to be eating all the time like the peckish snack nation we became, eating and snacking from early morning long into the evening (I was an absolute snack-monster in the past before I learned about insulin). The body is meant to have a rest time, to recover, after all it’s got such an awful lot of complicated jobs to do.

(Doug) #14

@never2late - good questions, and congratulations on being cancer-free.

In general, I would say no. Even fairly lean people have fasted for many, many days in a row, without apparent problems. People with substantial fat to lose have fasted many weeks, even many months; same deal.

I noticed the fast durations you mentioned. Even eating just once a day (unless it were to be nothing but fat) pretty well prevents any initiation of autophagy or increase in it in humans. It’s really not until the third or fourth day when autophagy is significantly increased/started.

It’s quite individual; some people hate longer fasts and/or feel really crappy on them. Even one given person may experience fasts differently at different times or ages.

To generalize, I think that there is value for many people in fasting. Or just “not eating” even if only for 12 or 16 hours. Insulin declines and one’s average insulin level for the whole day will be lower. For those of us who are insulin-resistant, that’s a huge and immensely desirable goal (regardless of the mix of fasting and ketogenic eating to achieve it).

While this isn’t about autophagy, per se, the benefits that many people have gotten from fasting, like from ketogenic eating, are impressive. Keto - again, for many people - provides metabolic healing, while fasting is what really made for weight/fat loss.

There is something to that, with certain types of cancer. There are more than a hundred types, so there’s no blanket statements concerning autophagy that will apply. In that NCBI article you linked to, reference #72 mentions nonsmall cell lung cancer. Or, #118 - with some types of prostate cancer, autophagy appears to increase cancer cell drug resistance. So, if somebody already has it, then I’d say maybe long fasts are not advisable. And it’s not always going to be “yes” or “no” - with some types of cancer autophagy both promotes growth and metastasis as well as inhibiting them.

There is a much more generalized positive slant for autophagy towards cancer in that autophagy’s “house-cleaning” prevents the development of many types of cancerous cells. Additionally, some types of cancer “eat sugar” and grow faster with higher blood sugar, so keto/fasting/autophagy should all be going hand-in-hand with fighting cancer, there.

Good point, Paul. The body tries to keep itself cancer-free, Sometimes, after decades of abuse, it needs a little extra help.

In general I think we can say that avoiding inflammation helps avoid cancer. Keto, fasting, autophagy - these all go towards stopping the damage and possible reversing some effects of what is basically ‘too much’ stuff, certain stuff, in our past. It’s not only with respect to cancer that benefits may be had. Cognitive problems and degeneration, Alzheimer’s Disease, etc., show some promise for prevention/treatment, there.

In some of our tissues, a low level of autophagy is supposed to be going all the time. And that’s regardless of sleeping or not, eating or not. Most of our nervous system is this way - composed of cells that are postmitotic. They can’t divide and multiply like in most of our tissues.

In tissues with cells that can divide, the effects of old,damaged, faulty cells are diluted out by new healthy cells coming in. But, for example, most of our nervous system is stuck with the cells it has. So, those cells need to remain metabolically active, alive, and functioning properly. Autophagy clears out the debris and damaged parts which can mess those cells up.


Autophagy happens no matter what, it’s part of what our bodies do, Fasting or not, Keto or not. Fasting just turns up the volume on it a little bit. We’re always breaking down old broken down proteins and cells and either recycling or trashing what’s damaged. Just like almost everything our bodies do, with very little exception, it’s self-regulating.

(May the blessing of bacon be always with you) #16

As Prof. Bikman says, catabolic and anabolic processes are always going on all the time; the real difference is whether the overall tendency is catabolism or anabolism. Proteins have a lifespan, and need to be broken down all the time; likewise, tissue building needs to be happening all the time as well.


This is interesting because I was reading the other week about cutting out glucose in an effort to restrict fuel to cancer cells, and one of the cancers where the cells transform to using non-glucose fuel sources was prostate cancer.

Which fits directly with what you go on to say - with the cancers that thrive on sugar, keto/fasting/autophagy does feel like a sensible dietary approach.

(Ohio ) #18

The beauty of keto is the ability to fast. The more you dial in your keto the easier it gets.

FYI. I also occasionally do green tea and chocolate however the caffeine will drive up your appetite later on. I counter this effect in chocolate by making my own with peppermint (& walnuts!) which is an appetite suppressant.


Hi thanks for your reply. I don’t know about any of the other cancers, there are so many, but what I had was breast cancer, a particularly aggressive and fast growing kind. I did as I remember while waiting for my first surgery, try to starve the cancer. I was barely eating anything then. And it might have slowed the cancer down, because although I had to have all my lymph nodes removed in my left arm, they actually only found the cancer in the one lymph node that was taken during my mastectomy. All the other lymph nodes were clean. I also had a full body scan at the time, also clean. So it might have been that my decision to eat hardly anything at all while waiting for my op was the right one. But then, when I was having chemotherapy, I did my research around that and as there was also some conflicting information regarding fasting during chemo and it potentially making the drugs less able to target the cancer cells, I chose not to fast. That appears to have been the right decision as chemotherapy was fairly uneventful apart from losing all my hair including eye brows. I joked about looking like humpty dumpty’s sister to my kids for a while, they were very OK with all the physical changes I went through. Anyway, it is difficult to say whether to induce autohagy or not in the case of cancer, I also have no idea if autophagy could be a harmful thing if you’ve had cancer in the past. But, apart from low energy which is an unfortunate side effect of Tamoxifen, I am feeling pretty good on my current WOE which I have been teaming up with IF. And I am hopeful this new ketogenic journey I am on will heal any metabolic damage sufficiently that over time my energy and health may further improve.


Yes I’ve noticed that too. My breakfast this morning after my usual walk was a 4-egg omelette with a side dish of 5 rashers of bacon. Haven’t been hungry at all after that heavy meal, but enjoyed a bit later a delicious coffee with cream. I have changed my eating habits so much on this WOE, how I ever could believe I was healthy the way I used to eat, snacking on dark chocolate, fruits and trail mixes constantly, is beyond me. Your chocolate version sound really good. Which is the appetite suppressant, peppermint or walnut?