Gua Feng Zhai gushu sheng pu'er

the 6th round; it stayed pleasant and kept transitioning

I'm trying the last sample of a set of teas from Tea Mania, shared by the owner Peter (many thanks!).  This represents the end of a number of sets of teas I had to try from the middle of 2025; kind of an interesting symbolic turning point.  I won't mind not reviewing much for a month or two, or if it's a slow year after that.  It's a nice experience related to trying the teas, but it involves at least an hour of focus and writing, and then more editing later on.  It's not the time that I'm short on, it's using up that much focus.

This tea was exceptional (I'm writing this just after writing the notes).  I think every single sample from them was, in different ways.  Some vendors are pretty good about only curating what works well.  Farmerleaf is sort of like that.  Yunnan Sourcing sells everything under the sun instead, which works in a different way.  Then it would be a different kind of discussion if their in-house versions are comparable.  I stopped ordering those roughly back when I first started to, just over a half dozen years ago, not because they didn't work out, but I just kept on exploring other things, and other sources.

I bought very little tea in 2025; flying back and forth to Honolulu and living expenses in that more expensive place shattered our Thai-based budget and income.  I bought a 500 gram Xiaguan tea ball locally last year, as an exception, in a Bangkok Chinatown shop (Jip Eu), but the rest I bought was mostly just gifts.  It worked out; I had some tea around to drink from before (as my wife tends to mention), and vendors helped by providing new teas to try.  I'm ordering a few inexpensive cakes from a favorite Vietnamese producer source just now, but in general I'll probably stick to that form this year too.

I get it why people buy teas like this one I review, more towards the $1 per gram scale.  They can afford it, and it represents a type of experience you can't access for 20 to 30 cents a gram.  There's something pleasant about drinking more basic, more limited teas too though.  The ever-escalating quality level or novelty theme experience expectations can be a sort of trap.  It would never be enough.  But then if someone can easily afford to spend a couple thousand dollars a year on tea then why not; there is range beyond this expense level that might even make sense.

I was going to add that past a certain quality level of material, or the experience enabled by one, it changes the experience to be one you can just focus on.  But maybe that goes too far.  I could drink a relatively basic Dian Hong, or even some good Darjeeling, or upper-medium quality green tea, and spend an hour outside in our driveway, between the garden spaces, watching our cats chase each other around.  The tea wouldn't be as refined, and it wouldn't change as much across infusions, but the basis of the experience is internal, not from that drink input.  

Maybe trying something new is a different thing; if this had been a Dian Hong I've already drank half a kilogram of the novelty of new experience wouldn't be there.  But still, I think cultivation of being present in the moment of a pleasant and extended experience is not tied to experiential variety, as much as approach and perspective.  It should be possible to drink ordinary tea in a shopping center parking lot and have a wonderful, peaceful experience.  I suppose the parts to tend to build up to the whole though, and an ocean view or green garden spaces would work better, and better tea.  

Like this one:

Gua Feng Zhai Gushu 2021  ($154 for a 200 gram cake)

Discover the exquisite craftsmanship of teamaster Panda with our Gua Feng Zhai Gushu, a distinguished tea known for its exceptional quality. Sourced from the renowned Gua Feng Zhai region, this tea is crafted from premium Gushu material, meticulously hand-pressed into pu-erh cakes at Yang Ming’s artisanal manufactory. The dedication to traditional, handmade processing and the careful selection of tea leaves are what set this tea apart, ensuring a product of unparalleled quality.

Gua Feng Zhai’s pu-erh teas are treasured for their rarity, produced in extremely limited quantities each year, making them highly coveted by collectors and tea enthusiasts alike. The Gua Feng Zhai Gushu is particularly suitable for long-term storage, with the potential to develop richer and increasingly complex aromas over time, offering a truly dynamic tea experience.

Harvest: Autumn 2021

Pressed: 2021

Typ: Sheng

Aroma: Strong, strong Cha Qi but also mellow taste

That's a bit heavy on marketing, but at least the tea is as good or better than the spin frames it as.  It's interesting that it's an autumn harvest tea.  Flavors and other aspects could vary some, but in general those tend to be less intense than spring harvest versions.  One comment here in the review kind of ties to that, but intensity was still pretty good.  Bitterness and astringency were quite moderate, so feel and flavor stand out more, especially flavor.

This probably is a high demand local area, as this implies, or more or less plainly says.  That would be why an autumn harvest version is being sold for this pricing, which for how good this tea is seems like a pretty good value.  I end up concluding that it seems good to me now, that waiting to see how it changes in another decade wouldn't make sense (mentioned in that listing, about aging potential), but I guess that's a judgement call.

It would've been interesting to see more of a flavor list in this description, since I'd guess that it has changed some in the past 5 years.  Those descriptions always vary by interpretation anyway, as the one that follows would.

Review:

Infusion #1:  the dry tea scent was really fruity.  Fruit comes across quite a bit in this first light infusion.  It's close enough to dried mango.  I'll probably keep changing that, or adding to it, but that works for now.  

The tea already has pretty good depth and balance, even though it's just getting started.  Complexity is limited, but it's not even wetted yet.  There's a nice mineral layer base, and creaminess.  That's more common in oolong but it can come up in some sheng, in a different way.  This tastes like pear too, now that I think of it.  That might be an overall favorite aspect inclusion, for me, when balanced with other flavors that match with it.

#2:  Pear, dried mango, and mineral base is already a good start for description this round.  There's a warmer range aspect that matches nicely with the rest, but it's integrated, not easy to describe.  As always in this range interpreting it as partly floral also works.  The two themes might even connect; chrysanthemum has a nice warm, rich, floral texture, and part of this is like that.  

It's complex enough that someone like Don Mei could go on and on describing this round for 10 minutes.  Maybe it does also taste a little like butter cookie, or like a yellow cake.  Maybe seeing it as including a hint of spice also works, just a touch of nutmeg, or maybe there is a light citrus edge.  Take all that with a grain of salt; it's complex, and there is more to it, but I think the first half dozen aspects that I mentioned make the most sense as an interpretation.

It's unusually good.  Does that come across in listing the flavor aspects?  It balances well, and that mix of depth, sweetness, complexity, and overall balance is just great.  There is enough bright range to complement the richer, deeper flavors perfectly, and it's just not a heavy or challenging tea.  Feel is full but aspects like astringency and bitterness don't really come to mind.

For being a 2021 tea this hasn't transitioned that much, but probably some.  This is where more gradual, not so hot and humid storage really shines.  In Bangkok this would've been heavier and further along by now, but it's better this way, I think.  It would probably good in a different way in another 15 years, but to me it's too good now not to just drink it.

#3:  it might integrate and balance even better, even though it's similar.  Mineral picks up, and it had been pronounced before.  I guess that's part of the "depth" people claim relates to gushu forms.  And then another part, or other parts, might be harder to pin down.  One positive input could just relate to it being this good.

Fruit does stand out less, giving up space for that mineral and warm richness.  I guess that also makes the floral range seem to stand out more.  You could probably emphasize the lighter, brighter flavor range by brewing this even faster (I'm using around 10 seconds), and ramp up feel and heavier aspects by letting it brew longer.  To me this is pretty good, a nice balance.  Maybe brewing it a few seconds faster would be as good, or possibly slightly better, and over a few rounds that would get you an extra round.  I'll try it brewed fast next round.

#4:  a flash infusion is probably a little too light.  It still includes plenty of flavor, but the feel thins out.  That really fast brew pacing is more for sheng versions that are overly intense.  A spice note like sassafras shows up, tried out this way.  Or maybe it was evolving towards that anyway.  Again it's quite pleasant.  

It has worked out well to try this tea last from the set of samples Peter shared; it's really pleasant and distinctive.  It will be interesting to see what this sells for.  It reminds me of a past personal favorite from Nannuo, that probably wasn't this good, but that paralleled some of these flavors.

#5:  spice range definitely picks up, but it's broader than the sassafras was last round.  Describing it clearly isn't going to work, even in parts.  One part is that, and another is a driftwood sort of sweet and dry woodiness, like how balsa wood smells.  Then that's rounded out with root spice, more like ginseng, maybe just not quite as punchy and medicinal as ginseng (which is also subtle, in a different sense).  It has changed a lot over the last three rounds.  That really short infusion approach could also relate to slowing the transition, or trying to, to get the most out of the tea where it's at in the cycle.  

Of course these flavors link well with the pronounced base mineral tone, which isn't dropping out.  Feel and aftertaste are significant, but those can be more intense in some other versions.  Overall balance is the nicest part, the way it all comes together each round.  Usually I'm bored with writing notes by this point but I'll describe one more round, even though it will probably change some after that.

#6:  it changes less than it had over last rounds.  Mineral and warm spice tones pick up enough that it's taking on a more savory character.  Probably as a much younger tea astringency and bitterness would have been a bigger input, and these warm tones wouldn't have been nearly as pronounced.  To me this represents when partial aging works, when limited transition can be positive, even without trying it then.  

Then again I would've liked the intense bright flavors when this was quite new, even with more bitterness and astringency included.  Bright floral range and lighter fruit range probably would have stood out.  It's nice like this; these warm tones work.  The tea retaining some light and bright range makes them balance well.  Again I wouldn't wait a few years to drink this to see how all that changes; it's in a nice place now.

2022 Lishan Tie Guan Yin, 2021 Formosa Tie Guan Yin

Lishan left, in all photos (much greener and lighter in brewed color)

I'm back to reviewing, covering two oolong versions from Tea Mania, a vendor based in Switzerland.  These were contributed for review, more or less, and also just shared by the owner as a tea friend (many thanks!).

Their teas are pretty solid, so I went into trying these with high expectations.  They lived up to them.  That can be a problem, expecting teas to be on the far side of above average, because if anything is missing some of the expected type-typical aspect range, and aspects that serve as quality indicators, or just isn't a tight match to preference, then it can seem all the worse, where with more neutral expectations that would just be normal.

I wanted to add a little personal update here as well.  I've just returned from living in Hawaii again for a month, staying where my kids go to school in Honolulu.  That was the second month long outing there in the last half a year, and I'll go back again in two more months, for the end of Keoni's senior year there.  It has been quite an interesting four year cycle.  Of course that education was the goal, and that part worked.  Switching over employment back to the US didn't.  Living between the two locations and cultures wasn't really intended.

I suppose because I've spent most of the last 18 1/2 years here in Bangkok, and I still spend far more than half the year here, there isn't really any adjustment to work through going back to Thailand.  In Honolulu I feel like I am adjusting for the first couple of weeks, and it could feel more natural for the entire first month.  Of course it's fantastic there; that helps.  I swam in the ocean, out to a flag about 200 meters out, at least a dozen times in a month.  Running goes better there, due to the cooler climate, just not so much this time related to an Achilles tendon problem.  

I met an interesting tea contact there this time, but left out telling that story, in part to avoid going through the permission step, and because there wasn't that much of a consistent story to it.  It felt like meeting new friends; it was nice.  Discussion was all over the place, as it should be.

No matter where I spend time with the kids things go great, so either place, or anywhere else, is suitable for that.

Back to business here; I'll try to look up listings for what I tried.

The first one I couldn't find; it's not this:  Lishan Tieguanyin  ($31 for 50 grams), even though that's also from 2022.  That's too oxidized; it really can't be the same tea.  Or maybe it is, and that just seems completely impossible to me. 

It's lighter, more like this one:  Lishan Medium Roast ($25 for 50 grams).  But that's made from Qing Xin cultivar, and it's not the right year either (from 2015).  They might buy a lot at one time and then be ok with selling it out over years.  It might be similar to this version, Gaoshan Tieguanyin, just from a different year, with that one listed from 2025.

That second one seems to be this:

2021 Formosa Tieguanyin  ($25 for 50 grams)

Formosa Tieguanyin, hailing from Pinglin and harvested during the spring season, undergoes traditional processing methods, resulting in a tea with a medium to strong degree of oxidation. This oxidation level is notably reflected in the green leaves with a delicate red edge, creating a  a beautiful amber liquor.

The aroma of Formosa Tieguanyin is robust and floral, a quintessential trait of spring teas, accompanied by subtle toasted notes that add depth to its profile. Its fragrance evokes hints of jasmine and magnolia, creating a harmonious bouquet. Depending on the quality of the water used, it may reveal a refreshing, slightly acidic note, adding to its complexity. As you savor this tea, you’ll notice a gentle spiciness and honey-like undertones in the cup, making it a truly multisensory experience.

One of the unique attributes of this Formosa Tieguanyin is its enduring finish in the mouth. The reverberation of its flavors persists over an extended period, inviting you to savor and contemplate its intricate character in meditative silence. Thanks to its traditional processing, this tea is well-suited for storage without compromising its aroma. Over time, as it matures, the aroma transforms, unveiling its own distinct charm.

Harvest date: spring 2021

Aroma: floral notes, reminiscent of jasmine and magnolia, honey undertones

Oxidation: approx. 50%.

Roasting: medium

Terroir: Pinglin, Taiwan

I'm more familiar with sheng pu'er pricing, so I won't be able to add much about the relative value of these.  Are they good for costing in the 50 cents a gram range?  I think so.  You don't find versions as inexpensive as some other types range for better quality Taiwanese oolong; it seems you pay to get versions in that category.  Up towards $1 a gram is normal, and the 50 cents per gram range for good versions is quite fair.

Maybe that's not so much, or maybe it's out of some people's budgets; it just depends on expectations.  But I doubt that you can find anything in a similar quality level in a lower price range.  There must be some decent oolong out there for less, but these have all been exceptional, well beyond decent.

I usually talk through input factors a lot more.  This doesn't discuss any differences related to Tie Guan Yin and more standard Qing Xin variations, and barely touches on the aging issue, that these are nearly 4 and 5 years old.  It works to just describe them.

Review:

2022 Lishan:  this is a bit overbrewed (ok, maybe even more than a bit); I was looking at something online and left it for over a minute.  Not ideal as controlled review processes go, but the tea will be fine.

It's a little strong, but still quite pleasant.  It will interesting seeing how a light version works out, the opposite sequence I normally experience both forms in.  Mineral tone is positive.  Feel is thick and full.  A vegetal range note is harder to place; it integrates well, and it's not negative, but it's less clearly positive.  This includes plenty of that type-typical mineral base and floral range, it's just in an unusual form for being brewed a bit strong.  

Nothing negative stands out; this is one purpose of using stronger infusions, to identify flaws better.  That vegetal range should lighten at a normal infusion strength.

2021 Formosa:  this is in a completely different flavor and character range.  It was more oxidized and more roasted, most likely.  I've always loved that effect when those two things balance well.  I think they will for this version, but again being brewed slightly strong doesn't show it's true potential, beyond highlighting that it doesn't include certain kinds of flaws.  

There's an interesting spice range in this, difficult to determine between root spice and bark spice range.  My first guess is that it spans both; it's quite complex.  One part actually is along the line of cinnamon, but there's a lot more to it.  It will help trying it lighter; that can work better for separating flavors.

Of course both have full feel and pronounced aftertaste expression, brewed a little strong.

Lishan #2:  creamy, light, sweet, and rich.  It is much better in a conventional infusion strength, but it wasn't so bad extra strong.  There's a characteristic high mountain oolong range this covers really well, a mix of base mineral, creaminess, and floral range.  I suppose this is probably identifiable as a region-specific example, and I've tried plenty of tea from different areas in Taiwan, but not enough over the last few years to stay familiar with that.  It's hard enough tracking how that goes for pu'er, which I drink much more of.  

If Tie Guan Yin is an exception for plant type for this area--which it says in a different product description--maybe the type-typical character would be harder to identify, without a lot of exposure.

It's very pleasant.  It didn't lose any brightness of freshness over nearly 4 years of settling (it's from 2022).  It probably did change, and if I'd been drinking a lot of oolong for the past half dozen years I could speculate about how.  Picking up depth?  Who knows.

I can't identify that bright floral range as a specific flower aspect flavor but anyone with even limited exposure with Taiwanese oolongs would already have a pretty good idea of what I mean.  It's not vegetal at all, in this form; that part switches back over, from when brewed too strong, back to floral range, and a flavor that actually seems a little like cream.

Formosa:  more pleasant, again, but of course just a lighter experience of the first round.  Those layers of warm and sweet spice really stand out.  Warm mineral and rich, round sort of feel complement them.  Sweetness is pleasant, for both of these.  Part of the warm, sweet range seems to resemble honey, or maybe that's caramel.  Or maybe both; this is on the complex side.  It's not far off dried fruit but I'm not noticing that standing out.  For being less distinct that could really be floral range instead.

Lishan #3:  maybe vegetal range does enter back in a bit, infused a little stronger than last time, but not overbrewed.  Intensity is good, but that was true when brewed quite light too.  Floral range is still pleasant, and creamy feel and some cream flavor stands out.  The mineral base is quite strong.  

This is exactly what many people would be looking for in a Taiwanese oolong experience.  It's familiar range.  I like it, I guess apparently just not enough to break from drinking pu'er all of the time to seek it out (and some black tea, but that's limited, more a main alternate).  I could drink this regularly and appreciate it.  In a limited sense pu'er seems more intense (sheng pu'er, I mean, of course), including bitterness, strong flavors, and a particular astringency.  But this is very complex and intense in flavor, and the rich feel and aftertaste provide secondary supporting experience.

Formosa:  I could speculate about another half dozen flavors being included in this, it's that complex.  But describing it as primarily in spice flavor range, a broad set of inclusions within that, and including mineral base, sweetness, and other range like caramel mostly gets it.  

It would work to interpret part as being a rich, heavy floral range, or seeing some of that towards-earthiness range connecting with dried fruit.  Maybe dried longan?  Only people who have tried dried longan would recognize how much of a compliment that is.  It's probably my favorite dried tropical fruit.  There's something so catchy about it that once you start eating it it can be hard to stop.  It doesn't stick around for long.  Of course once you think of the association it seems obvious, and accurate.  Let's say this tastes like dried longan, and set aside the rich floral part for now.

In later rounds the roast input didn't integrate as well, which is actually normal for this range of oolong.  I didn't take notes past these early rounds but it held up to brew quite a number more.

Both are really good.  Both are extreme examples of the positive potential of Taiwanese oolong.  I'm curious what the aging input contributed, nearly 5 and nearly 6 years for both.  They mellowed and deepened?  It almost had to be positive, given where these are now.  

There isn't a hint of negative aspect range in either.  That can be hard to appreciate, noticing something that isn't there.  And intensity and complexity is great for both.  If this more oxidized and roasted version isn't too costly it would be ideal for buying quite a bit of, to drink over the next decade, and then to experience as a truly aged version (which of course would seem all the more true after 20 years, not "only" 16).  

Looking back at the included price, added during editing, this is 50 cents a gram.  It could pay off to buy some to drink and some to forget about for awhile.  

I left out part of the personal backstory, about the tasting.  I had changed countries less than a week before, which didn't add too much jet lag, but I had cut my thumb hand-washing a knife earlier that morning, and went on to get stitches later.  I don't think it threw off my perspective much, but in retrospect it was a little strange doing a relaxing tea tasting between those two steps.  I didn't think the injury was so bad.

Our cats are just now experiencing exploring the outdoors, two kittens that are about half a year old now, or I guess maybe even 8 months.  That's not so distracting, more a pleasant step to witness.  They both just learned to climb trees this weekend.  I do end up getting up a lot, from a table outside, to check that they're not walking out into the soi / alley, going around our gate.  On a later day I climbed that tree myself, to help one down, since she hasn't figured out the down-climb process yet.

Life is all about those ups and downs, isn't it?  In two months I'll be a more direct part of my kids experiences, which I just hear about by video call now.  There's lots more drama when I'm not there, which I guess is partly a good sign, that I help keep it all tracking well when I am there.

Fasting basics, and a bit more on background and approach

this picture has food in it, but relaxing in nature with tea could be helpful while fasting

I mentioned that fasting may have improved my health in relation to aging aspects in a Reddit thread, and in a second comment covered basics on how to fast.  It all works as a great summary of the topic.  

Let's start with the first part, what seemed to improve as a result of fasting practice:

I'm really also pursuing health instead of avoiding aspects related to aging, or longevity related "biohacking." But I tried out fasting awhile back (maybe 2 1/2 years ago), and it seemed to make a difference. Now I try to fast for 5 days at a time 4 times per year.

It's hard pushing that to the next level for description, listing out likely benefits. I think I'm a little mentally clearer, and my energy level seems more stable, especially when running. That second part is a reference to metabolic flexibility; people are said to be able to use fat energy better when they routinely experience ketosis.

It's possible that it is offsetting other aging effects, but not in a way I can clearly link and justify. The few grey hairs I had mostly returned to being colored. That could've been for some other reason though; I exercised more around the same time, adjusted diet, and added a bit of supplementation to help with exercise recovery. My health checkup blood markers have all improved somewhat, but I'd expect exercise to be related to that.

Then someone asked about the details, in the form of these questions:

Curious about your fasting. Water only? For how long? How do you transition back to food?

My answer ran a bit long, since it seemed I could cover a few other basics, beyond those three questions:

Past 3 days you really need to supplement electrolytes, but that's it, sodium, potassium, and magnesium. People who fast often tend to drink things with no calories, and I drink tea or herb teas / tisanes, and sometimes a diet soda, but not often. I've never heard of anyone trying to eat something solid with no calories; that's not typical fasting. People avoid eating a single calorie, even though eating 10 to 20 might not re-trigger digestion response.

I try to fast 4 times a year for 5 days at a time. There's no clear reason for why 5 days at once or 20 days per year would be optimum; people sort out what they think will work on their own. Autophagy, a recycling process for inactive cells or damaged cellular material, is said to peak at or after 48 hours, but autophagy routinely happens to some extent, and that kind of hearsay input is only so reliable.

Transitioning back to food is a lot more difficult when you fast for 2 or 3 weeks, instead of 5 to 7 days. You can still get it wrong fasting for 5 days, but that has only happened to me once. I would normally eat a burger and fries to resume eating, but a natural version of it, using quality meat (pork; I live in Thailand and we don't eat much beef here), decent bread, home-made fries, often from sweet potatoes, and vegetables, spinach and tomato.

I once quit early for some reason and ate McDonald's food instead, thinking it would also work, but it didn't, and it took a couple of days to get past severe diarrhea. Beyond that, not eating fast food or junk, which is kind of common sense, people advise to avoid sugar. Probably moderating fiber right away would be as well, although you can eat a normal amount of it.

One benefit of fasting that may not be so intuitive is that it changes your relationship with food. The habitual eating, or "food noise," drops out. Not on the first couple of fasts, but eventually it does. You can reset to a better diet. You can only make so much change at one time, or it won't stick, but over the course of a few fasts you could completely reset what you eat and your related eating habits, and it wouldn't seem nearly as difficult as making extreme changes while still eating.

One potential negative, depending on how people see it, is that I think my metabolism might have slowed slightly, that I eat a little less and maintain the same body weight. I've gained weight in the last 2 1/2 years, but I've been exercising a lot, and I think it's mostly muscle weight. People discuss a risk of losing muscle mass during fasts but I'm certain that I don't. 5 days isn't that long a time period, and my body would have access to protein in my digestive system the first day.

To make it easier people recommend switching to a very low carbohydrate diet for a couple of days prior to the fast. Not necessarily to enter ketosis, but that is the general idea. An extreme version of that would be to not eat any carbs at all for 4 to 5 days, and you might enter ketosis then. If you are already using only fat and protein for energy, and mostly fat, it should be easier to switch to using body fat, in theory.

Later on you really do seem to take on greater "metabolic flexibility," an ability to use different energy sources, or at least it seems to me that I never feel any energy issues when I run, which I attribute to this. I'll run for 12 km for routine outings (3 times every 8 or 9 days) and energy level is never an issue, even though I'm 57, and everything works a little less effectively at this age.

And that's most of it.  I could add a little about what tea I tend to drink, given this is a tea blog, but that doesn't run long, because most types seem not to work well.  I can drink shou / shu pu'er, and sometimes go with aged white tea.  I would guess that some forms of hei cha would also be fine, and I've had positive results experimenting with that, but it would depend on the type.  Harsher Liu Bao wouldn't work at all, and milder Fu zhuan would probably be fine.

I think herb teas / tisanes are even more flexible, that few of those would upset your stomach.  I experience great results from drinking those, but I think it might be mostly because I'll brew a couple of rounds of a large mug of one, and drinking an extra liter of water is probably helpful.  You really should drink at least 3 liters a day while fasting, more than it feels natural to drink, and a full gallon (around 4 liters) is more the optimum people recommend.  Your body is said to use a lot of water by processing energy through ketosis.  

Again all of this is hearsay, which can only be confirmed so effectively through experimentation.  But I can notice that if I don't drink a lot of water I suffer negative effects, and that it takes a lot of electrolyte input to seem to balance that factor.  It's on the order of 2 grams per day of both sodium and potassium; an awful lot.  You don't need that much magnesium; maybe 400 mg.  All of this isn't dosing recommendations, and I suspect what works best for people would vary by a lot of factors, like body size, local climate (if they're sweating), rate of metabolism, energy use, and so on.  

Some people probably become very inactive while fasting, even though it works well for me to walk a good bit while not eating.  It's relaxing, and it takes my mind off not eating.  My thinking is that light activity helps over the first couple of days to switch over to full ketosis, so I'm not going through that adjustment period for three days, which seems to be the normal time-frame.  I've experimented with running while fasting, and that's fine, I can, but I suspect recovery is impacted, taking in no protein for days.  So I've never really pushed it, never running too far.  Maybe only 2+ miles / 4 km to test it out?

From there other factors seem vague.  People might try to do more meditation, to lean into a more spiritual side of the experience, or at least to offset anxiety that might come from the mild underlying stress of not eating.  I first fasted based on someone telling me that they fast for spiritual purposes, to replicate what yogis and Jesus experienced.  Maybe there's something to all of that.  It's a profound feeling experience.  I can't do it justice by description, and it takes a few fasting trials for the early stress to settle out, and for hunger experience to subside, so that you get on to experiencing different dimensions of it.

Then people might discuss how to deal with that stress and the "intrusive thoughts" part better, food noise.  All of that just varies by person, and largely drops out with more exposure, again after a few fasts.  Hunger experience really is extreme and novel the first 2 or 3 times.  I don't mean the psychological expectation either; your body is unfamiliar with the process, and doesn't know to drop the hunger trigger in the same way.  Put another way, in physiological terms, you seem to produce a lot more ghrelin in those early trials, and your digestion response doesn't slow down at all, instead increasing, but later on it's the opposite, and you don't think of food much, or hear your stomach growl, and experience gas, and so on. 

I guess one last part I didn't cover is that I recommend people start with no more than 24 hours duration.  Of course I didn't; I tried to start with 5 days, and then failed after three, when I noticed that you experience severe symptoms from not supplementing electrolytes, like trouble sleeping, muscle cramps, and what seem to be heart palpitations, an irregular heartbeat.  But it would probably be so much easier to do a couple of 24 hour fasts, then a couple of 48 hour versions, then 3 days, then 4, and so on.  I've never made it much past 5; a different form of acclimation seems to apply to go beyond that.  I'm sure with a few trials it would be fine, but for me 5 days covers what I'm pursuing, hopefully triggering an autophagy / health maintenance response.

Two more tangents

I could probably keep considering extra tangents at length.  I've participated in discussions of fasting practice and experience in a Reddit sub for a few years now (where there is a good electrolytes wiki reference), r/fasting, so parts keep coming up.  I'll stop at two last points, the first related to the input of artificial sweeteners.  Are those ok?  

People are in two different camps related to that.  One group thinks that those could potentially trigger an insulin release, which would be a bad thing, and that at a minimum their purpose in fasting is to avoid chemical inputs.  As an example, some people think taking a multivitamin makes a lot of sense, since you are skipping ingesting all nutrition, and others see it as a sort of cleanse function to keep intake of everything to an absolute minimum.  

No one really knows if there is a negative effect from drinking a diet soda, or sweetening tea with stevia or aspartame.  I mean related to fasting, but I guess there is also a broader concern about these things.  I've drank nearly a dozen artificially sweetened drinks over the last 2 1/2 years while fasting and notice no negative effects.  That's not much of a sample size, and the opposite of a well-controlled review process.

The other subject is perhaps the trickiest part of fasting, getting electrolytes sorted out (beyond not eating when you are hungry).  This problem comes in a few parts:  

-how much sodium, potassium and magnesium do you need?

-does it matter which compounds provide those, and which are optimum?

-what is the best intake form (eg. in a drink solution, should that be flavored, what can you take in a pill form, or what won't work in that form)?

-how frequently should you ingest it, or put another way, what dose can you tolerate at one time?

1.  (amount of electrolytes):  The wiki reference in the r/fasting sub provides input on this, but the high end of the suggested range there is awfully high (many grams of both sodium and potassium).  People need to experiment and sort out what works for them.  I've already mentioned a general range, about 2 grams each of sodium and potassium, and about 400 mg of magnesium per day.  That's not advice, not even offered as a starting point, just mention of the general range.  It's a lot.

One thing to keep in mind is that you are trying to ingest a certain dosage of sodium (for example), not necessarily sodium chloride.  The chloride part may work out to be essential, for all I know, but it's necessary to keep straight that calculating input of sodium, and the others, requires some way to account for the other part of the salt compound, what that contributes to weight (dose).  That wiki reference helps with that.

2. (which compounds to take):  for sodium it's down to sodium chloride (table salt) and sodium bicarbonate (baking soda).  I don't like the taste of baking soda in a salt solution, so I only use table salt.  For potassium the main form you run across is potassium chloride, so that's what I use, but it's not the only form.  You can buy it as a table salt replacement in grocery stores; I've bought it in Wal-Mart in the US and Tops in Thailand.  It costs almost nothing, and works well as a supplement to balance out your electrolyte input when you aren't fasting.

Then magnesium is where things get complicated.  I use magnesium oxide, because it's the cheapest, but people recommend different versions, or recommend avoiding different versions.  Over and over people say one compound has a strong laxative effect and another is relatively optimum, it just might not match which they prefer.  It would work to look up discussions in that group (sub) to use as input, maybe as a sort of voting process, going with what people tend to say the most.  Using a search function in any social media group is an extreme step, but it would work.

3.  (best intake form):  you can just take magnesium as a pill; that dose is so low that it wouldn't be a problem.  It might be nice if you could take it in the morning and then a couple of hours before bed, because it's said to support sleep.  

The other two, sodium and potassium, are harder.  The standard approach is to make up a solution of quite a bit of water and those salts and drink that throughout the day.  It seems to work well for me to treat that as a meal, to drink some at breakfast, lunch, and dinner time, and some in the evening.  Too much at one time causes a strong laxative effect, but breaking it into four parts offsets that.

People tend to not mention other tricks or approaches very much.  Since you don't eat anything there's no way to couple it with food, and it would make limited sense to drink a very salty version of coffee or tea.  I've mixed it with tisanes before, and that's promising, but it's too much extra work.  If you use a base flavor tisane and dried citrus rind, and a little sweetener (stevia, some chemical form, whatever) it is a bit like gatorade.  You need to keep drinking a lot of water to help process it, and support energy use from fat through ketosis.  Experimenting with what works for you seems critical.

4.  (maximum electrolyte dose at one time):  Again you'd need to experiment to sort this out.  I'm sure that ingesting a gram each of sodium and potassium at one time would go badly, for almost anyone, so you need to break it up into at least 3 different intakes, and 4 might work better, or others might prefer a half dozen.  

You might think a laxative effect wouldn't be possible, after 3 or 4 days without eating, but you would be wrong.  Apparently your body continues to release a limited amount of digestive fluid, which may drop with acclimation, so you can experience multiple very odd, liquid bowel movements over a 5 day period.  Ingesting a lot of salt / electrolyte at one time triggers that.  Not just magnesium either; the other two can have that effect.

In general my stomach feels better than one would expect; I have few problems or issues.  If I were to drink green tea or black coffee maybe that wouldn't be true.  I've had no problems with any tisanes, so it doesn't work to recommend which work best.

Conclusions

All of this went a little light on the benefits part, but I think that would vary by person, and my input would seem like claims that I really can't support.  Did it offset aging effects?  It seems so, but who knows.  Do I experience more metabolic flexibility, more energy while running due to more efficient fat use?  The same.  And mental clarity is the same; maybe that improved, but it's hard to identify, and impossible to be clear on causes.

I also skipped over lots of negative effects that occur in those first few trials.  Beyond being desperately hungry I experienced energy level fluctuations, sleepiness, dizziness, trouble focusing, and boredom.  I would go with my wife to a market or restaurant and that really heightened the desire to eat.  By the 4th or 5th fast all of that was moderate, and by the 10th or 12th I wouldn't be reminded that I was even fasting many times in a day.

There are periods of mental clarity and productivity that happen, after some exposure, that are also hard to describe.  At times I can get 6 hours worth of creative work done in an hour.  It's hard to focus or channel that; it happens when it happens.  It's possible to stay busier than normal, over the entire fast, but past a certain stress level it all seems to crash.  It adds some underlying stress, so you have to be careful.  You don't need to moderate the demands on your time and productivity, but you can't push it too far either.