[cracell]

Try what exactly?

I've done 24 hour fasts several times and they basically just make me lose two days of productivity. One during the fast day because I'm completely worn down and another the next day as I'm still drained and takes a day of normal eating to get back to normal.

[Dove]

Try keto adaptation followed by fasting, at least once in your life. I mean, there are people who can't for health reasons, and I don't know if there are others for whom it won't "work" . . . but if it works it's a heck of a thing.

[MattRix]

Fasting doesn't work for me except when I'm on keto, where it's no problem... though I should note I'm not talking about full day fasting, just "Intermittent Fasting". I will wake up, have a coffee+butter (~100 calories), and then not eat anything else until 2pm. Oh and I often run a 10-15km run before lunch and feel great during it, I think keto helps there too.

[DiThi]

I had similar experiences: When I'm on keto, I'm feeling hungry much less, and much less intensely. Sometimes I skipped lunch because I was focused on something and wasn't feeling like interrupting whatever I was doing. More importantly, I didn't feel super hungry a couple of hours after. I guess I was constantly in fat burning mode so my body didn't need to be switching gears.

I stopped keto after a few months reaching my target weight, and was irritable and unfocused for 2-3 days.

[sasas]

It's generally after the third day you start to feel better. A friend is doing this now and reported on the 4th day he has incredible clarity.

[chiefalchemist]

A couple months ago I read an article about how the immune system "reboots" after 3 days of fasting. I'm not read yet, but I've been considering making it a quarterly event.

[astura]

"Reboot".sounds very woo-y so I'll explain the science behind it as I understand it. Fasting, after your glycogen reserves are depleted, lowers white blood cells. This in turns triggers the immune system to generate new cells. This seems to be helpful in patients undergoing chemotherapy.

It takes about 48 hours to deplete your glycogen, that's where "3 days" comes from - 2 to deplete glycogen then a third for immune system regeneration.

I say, give it a shot for sure. It's a lot easier to do once you've done it before. I practice fasting regularly.

[Dove]

Some explanation from "The Complete Guide to Fasting" by Jason Fung -- a book I very, very, very highly recommend to anyone unconvinced that fasting is a good idea, or needing guidance on how to do it.

------------

There appears to be significant research indicating a dramatic drop in inflammation, improvements in insulin signaling, and a near total “reset” of immune function with fasts of 3–5 days. Abnormal and or pre-cancerous cells appear to be pushed towards apoptosis, which essentially selects for healthy cell types. In total this describes a process which should (in theory) reverse many of the signs and symptoms of aging while reducing the processes that appear to be at play in autoimmunity and cancer.

. . .

In a process called apoptosis, also known as programmed cell death, cells that reach a certain age are programmed to commit suicide. While this may sound kind of macabre at first, the process constantly renews cell populations, making it essential for good health. But when just some cellular components need to be replaced, a process called autophagy kicks in.

The word autophagy, coined by Nobel Prize–winning scientist Christian de Duve, derives from the Greek auto (“self”) and phagein (“to eat”). So the word literally means “to eat oneself.” Autophagy is a form of cellular cleansing: it is a regulated, orderly process of breaking down and recycling cellular components when there’s no longer enough energy to sustain them. Once all the diseased or broken-down cellular parts have been cleansed, the body can start the process of renewal. New tissues and cells are built to replace those that were destroyed. In this way, the body renews itself. But it only works if the old parts are discarded first.

Our bodies are in a constant state of renewal. While we often focus on new cell growth, we sometimes forget that the first step in renewal is destroying the old, broken-down cellular machinery. But apoptosis and autophagy are both necessary to keep our bodies running well. When these processes are hijacked, diseases such as cancer occur, and the accumulation of older cellular components may be responsible for many of the effects of aging. These unwanted cellular components build up over time if autophagocytic processes are not routinely activated.

Increased levels of glucose, insulin, and proteins all turn off autophagy. And it doesn’t take much. Even as little as 3 grams of the amino acid leucine can stop autophagy. Here’s how it works: The mammalian target of rapamycin (mTOR) pathway is an important sensor of nutrient availability. When we eat carbohydrates or protein, insulin is secreted, and the increased insulin levels, or even just the amino acids from the breakdown of ingested protein, activate the mTOR pathway. The body senses that food is available and decides that since there’s plenty of energy to go around, there’s no need to eliminate the old subcellular machinery. The end result is the suppression of autophagy. In other words, the constant intake of food, such as snacking throughout the day, suppresses autophagy.

Conversely, when mTOR is dormant— when it’s not being triggered by increased insulin levels or amino acids from ingested food— autophagy is promoted. As the body senses the temporary absence of nutrients, it must prioritize which cellular parts to keep. The oldest and most worn-out cellular parts get discarded, and amino acids from the broken-down cell parts are delivered to the liver, which uses them to create glucose during gluconeogenesis. They may also be incorporated into new proteins. It’s important to note that the dormancy of mTOR is only related to short-term nutrient availability and not the presence of stored energy, such as liver glycogen or body fat. Whether the body has stored energy is irrelevant for mTOR and therefore for autophagy.

This is why the strongest stimulus to autophagy currently known is fasting, and why fasting alone, unique among diets, stimulates autophagy — simple caloric restriction or dieting isn’t enough.

Fung, Jason; Moore, Jimmy. The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended (p. 151-153). Victory Belt Publishing. Kindle Edition.

[chiefalchemist]

Thanks. I'll have look into that book. Until then: How often is it recommended you do a 3-5 day fast? And is there a significant boost (?) from the first one, since in theory there's more junk to clean out?

[Dove]

The book in particular doesn't give a regimen -- it's more of a toolset approach. Here are your options, here are the goals they're useful for accomplishing, here are some tips, here are some dangers. I would definitely read it before embarking on a program (or even planning or choosing one).

You can also work directly with the author's foundation at https://idmprogram.com if you prefer.

With that said, he doesn't really talk about three to five day fasts much. It's kind of a suboptimal length. He talks about 24-48 hour fasts for weight and diabetes control, and 7-14 day fasts as cancer preventatives. The former is recommended multiple times per week, and the latter is recommended once per year. But again -- it depends on who you are and what your goals are.

[astura]

There is a lot of woo around fasting and the research, by in large, has not been done yet (if ever). So all we have is educated guesses.

My advice is just give 3 days an initial shot to see what it's like.

[bonestamp2]

Can confirm the 2-3 day transition and the clarity on the other side. But, you need to be well prepared for the transition and afterwards to ensure a worthwhile journey. Do lots of reading ahead of time to make sure you have everything you need to sustain after the transition.

[astura]

I think you're confusing fasting (simply abstaining from food) with some sort of religious or spiritual practice.

My first fast was 4 days when I was a teenager and it started as a joke "let's fast for the whole week then go to a buffet to see how much we can eat." That lead me to fast Monday-Thursday and we went to the buffet on Friday. Guess how much "clarity" that brought me? None.

[bonestamp2]

No, "simply abstaining from food" is not what I do. In fact, I eat quite a lot of food. But, it's the types of food that matter, which is what this thread is about. Being on a nutritious but very low (net) carb diet puts your body in ketosis -- it changes the way your body metabolizes food and stored body fat for energy. This is very different from fasting and/or abstaining from food and also very different from religion. The clarity is real and widely reported by others who achieve ketosis.

[Dove]

I would be careful not to overgeneralize from your personal experience, particularly not from a badly prepared / unguided experience.

A sense of clarity after three or four days is something a lot of people report -- certainly enough to say it is a real phenomenon. I don't know if the experience is universal, but it does seem to be quite common.

[astura]

Once again, you're confusing a personal religious/spiritual practice with the physical act of abstaining from food. They aren't the same. I never said it wasn't real, I certainly believe you feel it - If you're looking for a spiritual experience you'll certainly get one. I never said other people won't have similar experiences, in fact, cleansing rituals are a part of most of the world's religions.

It's just that you are not speaking of fasting itself, you are speaking of a spiritual practice that incorporates fasting.

Besides, I have a ton of experience fasting, I fast very frequently, short fasts every week (1 to 2 days), long fasts every once in a while, when I feel like it. I enjoy the physical feeling of fasting. I was merely speaking about the very first time I fasted.

[lotharbot]

> "you're confusing a personal religious/spiritual practice with the physical act of abstaining from food"

No, she is not (being married to her, I can speak with some authority regarding her intent.)

She does not fast as a part of a religious practice, but as part of a dietary one. And has likewise been reading dietary, not religious, guides to fasting. And it is a commonly reported experience for people to have a degree of increased focus/clarity on about day 4 of an extended fast. It can come in a religious/spiritual form, but can also simply be "man, I'm really on top of things today" -- as if the biochemistry of the body after 80-90 hours of deliberate fasting puts the brain into a mode of hyperfocus.