While she couldn’t do the several day fast, we found out that it was quite feasible to do the “one meal per day” thing, which shares a lot of the health benefits, and its a lot more forgiving.

I was under the impression that this was really unhealthy though. My BMI is 19 so I'm close to being underweight. Isn't this unhealthy? Do people fast and not lose weight?

The underlying psychological issues and associated stresses is what IMO qualifies as “unhealthy”, in which case corresponding under- or over-eating could result in malnourishment or excess weight[0]. However, in absence of these issues or other factors suppressing your body’s hunger/satiety messaging, not eating some “standard amount” shouldn’t be an issue on its own[1].

I happen to know a person who fasts routinely. In case of that person it doesn’t seem to be motivated by hidden psychological issues (he does not strike me as a person who could be suffering from body dysmorphia/anorexia) but by a conscious health choice. As an example of his logic, recently he got COVID and from his words he “simply” didn’t eat for two days and was right back on his feet feeling great. It’s not my place to question his choices, and I myself try to space meals to spend 14–16 hours without food every day since it seems to leave me feeling better, so it was surprising to hear but not too outlandish. He is not bulky but not skinnier than me either[2].

(I’m not a doctor, but from a cursory check medicine does seem to classify eating disorders as “expressive”, i.e. indicative of underlying issues. I don’t know how medicine treats under-eating without a cause, I certainly hope they don’t try to force-“treat” someone to make them eat at a level medicine considers “normal”.)

[0] For the record, I don’t think one can truly address those root causes just by eating less or more.

[1] In fact IIRC lower metabolic rates have been correlated with longer lifespans, at least in mice and in snails if not in humans.

[2] I’m slightly underweight, and can eat quite a bit without gaining much weight. My sister is similar, and she quickly gets low blood sugar shakes if she doesn’t eat enough. I guess it’s a sign of fast metabolism.

Interesting! Here's a challenge for you: could you buy — and eat — 5000 calories of chips/candy/soda per day for the next 90 days. You may not walk/run more than 5km/day, nor engage in other exercise for more than 30m/day.

Please weigh yourself before & after this experiment.

It's probably also better to ease into it. So start with an 8 hour eating window and slowly decrease the window.

Getting enough calories and nutrients can be a challenge and is far from easy with the "standard western diet". I would really recommend seeking advice from a professional.

Have you been to a grocery store in the last 100 years? Getting enough calories and nutrients is dead simple, our stores are overflowing with fresh fruit, vegetables, nuts and meat. What is the "standard western diet"?

https://en.wikipedia.org/wiki/Western_pattern_diet, also referred to throughout the article as "The Standard American Diet".

I meant the combination can be a challenge if your on a narrow time feeding window.

Yes, you say "maybe she had other compounding factors" which is equivalent to saying her case was idiosyncratic. In which case, why try to generalise it at all then?

When I look around the city, I see a lot of underweight women of all ages, including childbearing age — whatever the hell we're defining that as.* Many of them will be underweight by skipping meals, full on fasting, or eating and forcing themselves to throw it up later. This is the society, the mentality we have created.

Some of them I am friends with, others I have never met but write about it. Some claim to struggle with fasting, others fast and mention nothing about the difficulty or ease, and others struggle to eat enough. And some eat whatever they want and don't regulate it at all.

The takeaway is that when it comes to nutrition, there are a lot of factors and every case is idiosyncratic. There are no general rules other than "eat so you don't die", "don't eat so much you explode" and "don't eat toxic or corrosive chemicals". And even then, different people will have different tolerances to not eating, eating too much, and eating poison.

Nutrition is poorly understood, poorly communicated, and the driving factor behind the freight train of bullshit marketing telling people that they need to be wafer-like, elven creatures.

Full transparency, I'm underweight according to what I'm sure is actually a pretty shoddy measurement of weight...ness, but I don't do anything special. I fast quite a lot but I don't actually have a fasting regime, it's not planned, I just don't eat for extended periods of time.

When I do eat, it's really not a remarkable experience so I don't feel a need to change my behaviour. I eat enough to not die or suffer health problems thus far.

_____

* Since it will be a subset of {all ages}, my reasoning is covered.

He said they later learned it's known that women react to fasting differently and can have negative side effects, which we also discovered from our doctor when trying to get pregnant - so don't really see anything anecdotal there.

My point is that any nutritional thing is anecdotal because people don't neatly slot into a category when it comes to nutrition.

Also echo the mental clarity side of fasting. The weight loss was great, but how I felt was even better.

The crazy thing is, if you can get to 7 days, anything past that is just mental and you can go as long as you have the body fat to sustain the fast, provided you're keeping an eye on your electrolytes and not drinking too much water.

Don't you think it's too dangerous to name it essential life experience and recommend it to random people on the internet?

I'm really asking, I'm not knowledgeable about this at all, and my questions stem from pure gut feeling.

Obviously if you feel differently, talk with your doctor. I am not a doctor, and this is not medical advice. I thought that went without saying on the internet, but just to be extra careful, there it is.

Couple of caveats in the almost. Pregnancy, Eating Disorders, Elite Athletes functioning at under 5% bodyfat, and again the key word being _healthy_ here. If you have any kind of condition, disorder, disease, etc. obviously talk to a medical professional.

Most people just don't have the desire to do it, and if you're not used to fasting and eating a standard diet, the first few days will make you feel terrible both physically and mentally. Just like anything, it gets easier with practice.

That's sort of the rub in cavalierly recommending things to the general population, even when they're only somewhat extreme. There are plenty of undiagnosed conditions out there, and the further you move from the center of the distribution, the more you're going to sweep up potential risk in ways that aren't easily caught with a simple "not applicable if".

I say this as someone who fasts pretty often, though usually not more than 2 days. It's the same reason I wouldn't recommend everyone go out and take 200 mcg of LSD, "unless you have a mental health condition". This world of perfect information about one's own health that you're imagining simply doesn't exist. (Again, I say this as someone who thinks LSD is wonderful and salutary and has recommended it to many many friends in person with the appropriate personalized caveats).

Perhaps someone here with medical experience can chime in, but I agree 7 days seems a bit extreme for most people.

The only major health risk is refeeding syndrome, and even then it's only really notable if you're an alcoholic or have anorexia. If you're otherwise healthy with normal sodium/potassium/etc. intake and you take it slow when refeeding, I don't think it's particularly dangerous. Obviously, talk to your doctor, and it's probably good to get blood work before doing something like this.

There's just not a metabolic pathway for breaking down muscle/organ tissue for energy when you have adequate fat stores. We would have died off as a species a long time ago if that were the case.

In the grand scheme of things, if you have the body fat, 7 days is nothing for a fast.

Edit: To those asking, yes. I fasted for 60 days, water and electrolytes, no calories.

I remember his post from a few months back - found it rather inspiring.

Quite frequently I hit over 10k steps/day on my step tracker, sometimes double that. I live in the middle of a major city and walk everywhere, and this was before work from home.

If you’re looking for exercise/fasting advice check out my fat per unit time post elsewhere in this thread.

Humans have weathered long durations of food insecurity for much of their existence. If the default metabolic solution to fasting was harvesting energy from skeletal muscle and smooth muscle... well that strategy wouldn't work for very long, would it? The lowest hanging fruit is muscle/liver glycogen, and fat mass after that.

Breaking down proteins (gluconeogenesis) is a metabolically expensive process, requiring large energy input for low energy output. The body is wholly invested in protecting these vital organs. Skeletal muscle has a reputation for being fickle, subject to change based on stimulus and energy demands, but those adjustments are most significant and relevant to those who are invested in maximizing lean mass (athletes, bodybuilders, statistical outliers).

Fasting is relatively protein-sparing, all things considered. The observations of apparent muscle loss can be attributed to loss of muscle turgidity - a reduction in glycogen, intracellular fluid, and electrolytes. The difference between fed and fasted states, both visual and internal perceptions, are quite extreme.

Are extended fasts ideal, or even generally recommended, for someone with the singular goal of building muscle? Absolutely not. But it is a flexible tool when goals shift towards catabolic outcomes (losing weight). Furthermore, the downstream benefits of fasting can translate to improvements in insulin sensitivity, nutrient partitioning, muscle-building, and body composition... which are relevant to anabolic outcomes.

"A 27-year-old male patient fasted under supervision for 382 days and has subsequently maintained his normal weight."

By comparison 7 days is trivial. More to the point, a 7 day fast with medical supervision should be safe, if it is not, the supervisor will advise against it.

A better way of looking at it is to take it incrementally

* skipping breakfast

* skipping breakfast and lunch

* skipping a whole day

* eating one meal every two days

* eating one meal every three days

* ...you get the point...

I don't think OP would advocate just jumping right into it. Start small, work up from there, listen to your body. You wouldn't jump right into running a full marathon.

I believe I say multiple times in this thread nobody should just jump in and do 60 days, however I believe anyone (caveat-ed up thread) can 'jump in' and do 7 days at any point in their life.

It won't be easy, it'll be especially hard if you've never fasted before and are on a standard diet, but it won't be dangerous. It'll just probably be the most difficult physical and mental thing you've ever done.

Also, thanks for linking to my spreadsheet up there.

I'm not sure starting a western diet without medical supervision is a better idea given 75% of the west is overweight or obese. Unless you have medical conditions a 7 days fast is a walk in the park in term of health

Mistake 1: Drinking pure water. Your body does need some specific minerals even when fasting. Cole Robinson, a fasting focused youtuber (who is not for everyone), has shared a Magnesium, Sodium, Potassium, Sodium Bicarbonate & Water recipe he calls Snake Juice that keeps electrolytes steady during a fast.

Mistake 2: Drinking liquids that break the fast. I've watched youtube videos of fasters add things like diet soda, gatorade, and even jello to their fast. That defeats the whole purpose and negates any positive effect.

It's not that easy. You have to properly substitute electrolytes - sodium, potassium and magnesium. And that is almost impossible without small doses of carbs.

My longest fasting was 42 days. I did 28 days three times before. I'm fasting more or less regularly (once per year) for about 25 years.

Don't do very long fasting without guidance of a doctor. Your heart needs properly balanced electrolytes.

EDIT: I've just seen your other comments here also underlining the need of electrolytes. I still leave my comment here for the other readers ...

From what I've seen there is actually research into it and the weight loss/fitness benefits don't seem to be any better than any other calorie restriction when equating calories (slightly worse for muscle mass when combined with exercise in one study IIRC), and other claims seem overblown.

Layne Norton has a couple of good study reviews (eg. https://www.youtube.com/watch?v=0PyBoKSv2tI)

That being said - this is highly individual stuff - even if something doesn't work for 99% of people - it doesn't matter if it works for you - and it's easy to try.

It's just important to have realistic expectations about these things, because overhyping tends to lead to motivation spikes - you get enthusiastic and then you get disappointed and crash to 0.

I recently did a significant amount of caloric restriction, from probably 2500/day down to more like 1500/day. The first day was awful. The second day wasn't so bad. By the fourth day this new amount of calories feels fine. I had to give myself permission to do basically nothing for several days though because I just didn't have it in me.

Whatever you need to do or narrative to tell yourself why you don't need to eat, do it. Keep busy, work, clean the house or volunteer. By keeping occupied, the mind will not seek food out of boredom and ritual.

Eat once a day. Typically I "reward" myself with the evening meal after fasting through the day. There are different kinds of fasts but the one which seems to work best for me is 1-big-meal a day type fast. The rest of the day, I can drink water or black coffee.

1) Remove from your mind the idea that huner is suffering. It's all in your head. It's merely a mild discomfort.

If you ate last night and woke up in the morning, you are not hungry. You are just used to eat in the morning. Your body will not suffer any thing from skipping breakfast. It alerady has more than enough energy storage. It was designed to tap into it.

2) Surround yourself in a virtual environment where fasting and accepting hunger is the norm and expcted and obvious thing to do.

Read blogs about fasting. Watch youtube videos about fasting. Read books about fasting. Watch how people who consistently fast are healthy and fit.

3) Understand that there are two types of pleasure. Fleeting pleasures, and lasting pleasures. The fleeting pleasure are the sensual. They are momentary and quickly go away. If you spend your life chasing fleeting pleasures, you will be miserable.

Lasting pleasures - if you can call them so - are mental states. Contentment. Feeling in control of your life. These don't come from things. They come from what you value and the way you conduct yourself in the world. If you have no value, you will be controlled by your desires.

Some people think this is freedom: to do whatever you desire. To me, it's slavery. Because when you follow this path your life will be miserable.

Some people try to cheat by pretending that their misery is actually happiness. You see it in the people who insist that fat is healthy and beautfil and hot!

4) Understand that your mind is distributed. Even if you resolve to fasting, there will be some component of your mind that really really wants to just keep eating. Sometimes it might come out and win. Accept that such a thing could happen. When it does happen, don't be too hard on yoruself. Try to understand why it's happening. But anyway, go back right away. Understand that many other components of your mind want to continue doing the right thing.