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Comment by rcombine | Hacker News Reader

>The well-known “8 x 8” rule — you should drink eight 8-ounce glasses of water a day — is not only daunting, it’s unfounded. In fact, nobody is sure where the idea came from, and science doesn’t support it. “It has no basis in fact,” says Michael Farrell, a professor at Monash University in Australia, who studies how the brain responds to thirst and other sensations.

> The average adult woman should consume about 11.4 cups of fluid per day (a cup equals 8 ounces) and men should consume 15.6 [...] Subtracting the 20% of water consumed through food, that means the average woman should drink about 9.1 cups of fluid daily, and a man should drink about 12.5.

8 times 8 ounces per day of fluid is 64 ounces of fluid per day, whereas ~9 cups per day of fluid times 8 ounces/cup is ~72 ounces of fluid per day. So isn't the recommendation actually _more_ than the 8x8 adage?

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It could have from Dr. Benjamin Batmanghelidj, author of Your Body's Many Cries for Water in which he claims that chronic dehydration is the source of most disease (and thus water is the cure). The 8x8 was a minimum threshold for his water treatment protocol as I recall. According to Dr. Batmanghelidj, feeling thirsty was not reliable as an indicator of need for water, as dehydration was more likely to manifest as pain or hunger than a feeling of thirst. His methods have been called into question. however.

Potential controversial opinion but what could really be wrong with: “When you’re hungry eat, when you’re thirsty, drink”.

Sorry but they just seem like such automatic functions I don’t see how it needs to be complicated any further.

Oftentimes what you think is hunger is thirst.

Babies who have stomach trouble sometimes over-eat because they mistake stomach pain for hunger.

So instinct/reactions aren't failsafe. Especially when we've loaded our diet with addicting things.

> Oftentimes what you think is hunger is thirst.

Anecdotally, often my thirst is disguised as looking for something to snack on that will cause me to salivate, like chocolate.

When I make a conscious decision to have a big glass of water or two, the craving goes away.

"Hunger" is more a function of time than a function of need, for one thing.

It is a variadic function of unlimited number of variables. :)

I' am pretty sure my meter is broke, I don't feel thirsty at all and have to consciously keep track of my "thirst".

To the point of not being able to sleep for a good part of 2018 due to severe pain, I couldn't lie down in any position or my body would ache terribly. It only got fixed after my wife asked me how much water I drink during the day, I had to think about it and my response was baffling even to me "ehr... one glass?". The sleep issues went away after a couple of days drinking more water.

Is anything weird going on with your serotonin levels? Genetic mutations? Antidepressants?

I seem to get dehydrated quite frequently as well. I simply forget to drink water and rarely do I get the thirsty feeling.

A good way I found to gain more sensitivity on whether i'm thirsty or hungry is to separate the two during meal times. When I have breakfast or lunch, I don't drink any water or juice, unless i'm having trouble getting it down my throat. I either do it half an hour before or after. I've been doing this for years now and now I can accurately feel when i'm truly thirsty or hungry. shrugs try it..

> unless i'm having trouble getting it down my throat.

If you have to get that far, are you certain to do the best job for your health?

Along those lines you could say “when you want something sweet eat something sweet” but that wouldn’t be good for your long term health.

But many people prefer routine and automation. Routine helps avoid wasting time and mental efforts by staying alerted to how exactly you feel at all times, not to mention the ease to misread your feeling.

I can only speak for myself, and find it really challenging to reliably evaluate my hungriness/thirstiness. If I can get hungry just by looking at food, or if I end up eating way too much because I've thought I was hungry (I wasn't!), then how on Earth can I possibly rely on such elusive indicators?

> Potential controversial opinion but what could really be wrong with: “When you’re hungry eat, when you’re thirsty, drink”.

That's how I got really fat.

The pop science consensus has been that the human evolved for a world of food scarcity, and when confronted with an unlimited supply of food, that system breaks down. That seems pretty plausible to me, looking at global obesity rates.

I am sure bamboozled meant it as a lower boundary.

In my opinion it works with food for almost all people and with fluids for many. I also drink more than enough just be drinking when I am thirsty. Some friends and also commenters here mention that their thirst doesn't work as well. So key is to know whether you can rely on your thirst.

>Potential controversial opinion but what could really be wrong with: “When you’re hungry eat, when you’re thirsty, drink

People forget to hydrate all the time, and can ignore their thirsty signals, or even not feel thirsty...

It's possible that until very recently we didn't have that much salt in our food, and so we didn't have time to evolve a proper response to that. And by "very recently" I mean a mere 200-300 years ago. Consider that in many cultures spilling salt is considered a bad omen, that most likely means salt was scarce not long ago.

Water + electrolyte imbalance are pretty big together. Unfortunately, people have been told to reduce salt, drink more water... etc. combined with refined, heavily processed foods. Confounded by the fact that too little of one electrolyte has similar symptoms to too much of others.

Most people don't even understand how to listen to their own bodies anymore, and doctors are more concerned with prescriptions that treating underlying issues.

> Most people don't even understand how to listen to their own bodies anymore, and doctors are more concerned with prescriptions that treating underlying issues.

Well said! It is the sad truth that doctors can be coerced by private companies into personal monetary benefits from selling their products.

The pop-sci wisdom is that what you get from the hypothalamus is a generalized primal desire. It may be triggered by thirst, but you experience it as a longing for food, sex, or sleep instead. Sometimes all of the above.

When you feel like this, you can recognize that thirst is also a likely explanation, and reach for water quickly and cheaply as a debugging step. At least rule it out before making tradeoffs to placate more expensive needs.

Well the first one is drinking straight water 8 ounces of water 8 times a day and the second statement is you need to drink that many ounces of fluid regardless of source. That includes the foods you eat and any liquids you drink. I think even the diuretics are included in that second figure.

Subtracting the 20% of water consumed through food

Sure sounds like the "8x8" recommendation (why not just say "half a gallon" or "2 liters"?) is actually a reasonable lower bound for what people should be drinking then.

Except it's well known that that is way too much water unless you are sweating a lot. If you drink that much, you'll just pee a lot, it won't actually do anything useful.

Since the article got something so basic wrong (and if it was intentional you would think they would mention that the numbers were similar), I decided to stop reading the article at that point, I don't need incorrect information.

Maybe it's an editing mistake?

The actual amount of water you need varies by exertion, and diet and all sorts of things, it's not a fixed amount.

Yes agreed, it's not helpful to search for a constant consumption requirement. A healthy and sedentary person, with a reasonable diet, on a cold, gray, damp day, does not need to consume much water.

>The actual amount of water you need varies by exertion, and diet and all sorts of things, it's not a fixed amount.

I completely agree with this statement.

>If you drink that much, you'll just pee a lot, it won't actually do anything useful.

I drink on average 6L of water a day. When I first started water-only fasting I was urinating constantly. I discovered that this was because I would drink a lot in one sitting, (as a 'meal' replica) and then interspersed throughout the day.

Once I changed my consumption style to ~150mL frequently I found that my body used the water better. Once it realized that a "constant supply" was readily available (and didn't need to worry about feast/famine cycles) I retained what I needed and more casually urinated the processed water.

My body can better manage itself when I drink 150ml 40x a day then it can manage 1L 6x a day.

If the body was previously worried about "feast/famine" of water before, wouldn't it retain water rather than pee it all out?

The body doesn't really have any way to retain [liquid] water without causing medical issues. There's no storage compartment except for fat that could be metabolized into water.

You can also store water, for a short time, mixed into fiber in food that was recently eaten.

But drunk more gradually thorugh the day, it is able to be 'retained'?

Asking in good faith, taken independently each of your comments make perfect sense to me!

I'm not implying I have 'water pouches' or anything as silly. 1.5L of water in my stomach gets processed as quickly as my kidneys can manage. Thus I urinate out a large % of that liquid intake before use can be made of it.

Continually drinking small amounts doesn't overwhelm my stomach and therefore it feels like I urinate less, and 'retain' that water.

Wow, 6 liters? you drink 40 times a day?

(24h - 8h) * 60 min/h / 40 = 24 min

So you stop what you're doing every half an hour and drink get a glass of water and drink it? Or do you have constant supply at your desk or how are the logistics?

I have a 1.5L Naglene bottle at my desk, and a water cooler 10 feet away in front of the server-room doors.

So cold water is always close.

I also drink when I'm at home.

I don't understand why you're downvoted. At the very least, the article is inconsistent on this point:

8 cups / day is widely reported - and suggested in the article itself - to be too high as a minimum, and yet the article actually ends up concluding that you need to be drinking more than that.

What people often take away from that is that they should drink eight glasses of water _in addition to_ everything else they might consume--soda, juice, coffee, and anything else that has water in it. And they think there's a rule they need to adhere to, and not trust the fact that our bodies are actually pretty good at letting us know when we need water.

>soda, juice, coffee

Don't consume these. They have the opposite effect of dehydrating you.

If these have a dehydrating effect, it will be (literally) drowned out by the amount of water consumed. It will be a vast net-positive.

I was always told that when growing up but I never understood how drinking soda would actually cause a net loss of fluids. A quick search shows that my suspicions were correct. Even though drinking soda doesn't hydrate you as much as drinking water, it does not dehydrate you.

https://duckduckgo.com/?q=does+soda+dehydrate+you&ia=web

This is one of these often repeated half-truths: See, for example, [1] and many many more.

[1] http://www.bbc.com/future/story/20140402-are-coffee-and-tea-...

If that were true, we'd have mass dehydration deaths on the daily.

You would need to drink a massive amount for it to be lethal.

Instead what you see are obese individuals because drinking soda has the net effect of making you more thirsty, causing people to drink more soda. Which is exactly what the soda makers want you to do, and will fund studies to make you believe otherwise.

If you truly believe that these will net-dehydrate you, it should be pretty easy to prove - just survive for 1 week drinking only soda/juice/coffee. If you die of dehydration, we'll admit you were right :)

I can confidently admit that when I was a stupid teenager, I had consisted on Soda & Coffee and potentially only getting raw water content absorbed from foods for multiple weeks on end.

I've survived for years drinking mostly iced tea, with a soda in the morning instead of coffee. I can count the number of times I drink plain water in a week on one hand (after exercise, basically)

> bodies are actually pretty good at letting us know when we need water.

My body certainly isn't.

Then you need to see a doctor about that.

What kind of psycho drinks water by the 8 fl. oz. glass?

I had to look up what 8 fl oz is in a sane unit(236ml), and that seems perfectly normal to me - pretty much all glasses that you can buy here are 250ml. If you buy a 330ml can of coke you can usually pour most of it in with some left for a top-up.

I wouldn't call anyone a 'psycho' for not adhering, but personally I'd typically pour a pint (568ml) of water, at home.

Of course, at any restaurant glasses given with water for the table are going to be somewhere much nearer your 236ml, so there's really nothing psychotic about it.

> Of course, at any restaurant glasses given with water for the table are going to be somewhere much nearer your 236ml, so there's really nothing psychotic about it.

Bingo. It's not hard to sip on a average sized glass of water during a meal. I routinely kill a 750ml water bottle at the gym or when hiking.

The distinction is between “8x8 glasses of water, independent of all other fluids you ingest” pseudoscientific rule, and “9.1 - 12.5 glasses of non-alcoholic fluids, which includes juice, milk, coffee, tea, etc, not just water”

Drink 6 cups of coffee, a glass of OJ, and 2 glasses of water would be just fine for an adult Woman, but the “rule” convinces people they’re still falling 6 glasses short of water.

Six cups of coffee?! I think you might have other problems.

Your body gets used to it and it basically feels one cup of weak coffee followed by five cups of water.

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