Drink Less Water?

White-haired woman in white shirt standing in kitchen pouring water into a glass.Dear Mark,

I always hear that I should be drinking eight glasses of water a day, but it takes a lot of unnatural effort to get close to that. Is it just me? What’s your take on the water rule?



As you know by now, my job is to question Conventional Wisdom. One of the classic health paradigms I’ve always had a problem with is the blanket recommendation by the general health community that we all should be consuming copious amounts of water. It just doesn’t make sense to me and it never has. Face it, Grok did NOT walk around with a canteen or an Evian bottle affixed to his loincloth. He and the Grok family thought Nalgene was the name of the tribe across the valley and they never owned a sippy cup with which to gulp down mass quantities of H20. Day after day it was a drop here and a mouthful there – if a source of water other than a dewy leaf was even available. Since Grok and his cadre probably didn’t spend too much time hanging around the water hole. (All those predators you know…) 8 glasses of water a day is unlikely a physiological necessity, not to mention an evolutionarily relevant model. Grok obtained most of his water directly from the food he ate, and I believe that we probably should, too.

I don’t get thirsty very often. I rarely drink so much as a single glass of water during my normal daily routine. When I was a runner, and later as a triathlete, I would go out for long runs or rides without much water – if any at all. Sure I’d drink a bit to recover lost sweat when I returned home, but if I was riding for less than two hours, or unless it was unusually hot, I didn’t even put a water bottle on my bike. Even today when we take a break playing Ultimate Frisbee on hot Sunday afternoons, I have to force myself to drink sometimes when I might just as easily skip the water altogether. Meanwhile, I see people at the gym with 2-gallon bottles of Arrowhead, fully intent on polishing them off before dinner, thirsty or not. So, am I flaunting conventional wisdom at my own peril? Or am I just doing what comes naturally to a Primal being?

Water drop

Years ago someone put forth the idea that we all needed to drink 8 glasses of water a day. Perhaps it came from a series of studies in the 1940s after which the Food and Nutrition Board of the Institute of Medicine opined that the “RDA” for water should be roughly 1 ml per calorie consumed. At their recommended 2000 calories a day, that worked out to 2 liters a day, or roughly 8 eight-ounce glasses. Lost in the translation somewhere was an important caveat that much – if not most – of the water we required could actually be obtained from the foods we eat. In other words, it simply was not necessary to actually drink 8 glasses a day. And since the recommended diet at the time included substantial portions of water-sopping grains, maybe that initial recommendation was too high for someone eschewing grains altogether. (On a related note people will tend to drink more if the beverage is flavored. And, guess, what: carbohydrates (particularly sweet tastes) encourage increased fluid intake. So, it’s useful to ask if the hankering is real thirst or a flavor related craving.)

Nevertheless, over the years, this hydration mandate has become burned into the health consciousness of most people. It appears that nearly every health guru (except yours truly) hammers on this point. Food doesn’t seem to count at all anymore. Eight means eight. And forget including coffee, tea, soft drinks or beer because Conventional Wisdom says that these are diuretics and therefore only increase your requirement for pure water. Of course, that’s wrong, because coffee, tea, soft drinks and alcoholic beverages do actually add to water intake rather than detract from it. Alcohol and caffeine only become significantly diuretic in very large and otherwise dangerous amounts. But I really wonder if all that extra water – however you take it in – is necessary or even healthy if you are already consuming lots of vegetables and other healthy Primal Blueprint food. The average person is said to obtain 20% of his/her water from foods throughout the day. If the bulk of your diet is vegetables and fruit, this percentage is assuredly higher.

Water Glass

Contrary to what your neighbor might advise you, there is no evidence that drinking eight or more glasses prevents constipation, kidney stones, bladder cancer, urinary tract infections or that it guarantees you’ll have clear skin and a toxic-free liver. Yet these are often cited as the main reasons to drink so much. And forget the so-called hyper-hydration properties of “clustered water,” “ionized super waters,” “penta-water” and the rest of the scam-waters, about which I have blogged in past posts. Water is water is water.

On the other hand, there are some possible health consequences of overdoing this hydration thing. Chronic over-consumption of water can cause the relative concentration of important electrolytes in the blood to drop, a condition called hyponatremia (Wikipedia), which in turn forces water out of the bloodstream and into cells, causing them to swell. Not a big deal for a muscle cell, but catastrophic when it’s a brain cell and there’s no extra space to expand into. Each year we read about people in endurance contests who sweat profusely, overcompensate by replacing the water but not the salts and wind up with cerebral edema. Last year a woman died in a radio-sponsored “water drinking contest,” drinking only about two gallons in a short period of time. Of course, those are extreme examples, but I do have several readers who have shared with me their intent on getting “100 ounces a day”, and I have to advise them to cut way back.

(The following contains my own personal hypotheses. I would love to see some research done in these areas. If anyone is aware of any please drop me a line.)

Conventional Wisdom suggests that drinking water with your meals is fine – even recommended. But I suspect that some heretofore undiagnosed digestive issues may arise when people drink significant amounts of water or other fluids with their meals. The digestive process starts with, and depends on, a very acidic environment in the stomach (a pH of 1 to 2 ideally). That highly acidic environment also controls the timing of when the stomach empties. When you drink lots of fluid at a meal, you are substantially diluting the stomach acid and diminishing its ability to effectively digest your food. I would guess that many cases of GERD, gas, stomach upset and other common complaints might be addressed simply by NOT drinking so much water throughout the day and refraining entirely from drinking while eating. (Except maybe a little wine, which, having a pH closer to stomach acid has been shown to aid in digestion) This might also explain why some proteins that only break down under optimum acid conditions pass into the intestines only partially digested and thus might be recognized by the immune system as “foreign invaders”, setting up some immune response that gets diagnosed as a food allergy.

Furthermore, unbeknownst to many people, the stomach is one of the first lines of defense in your immune system. Bacteria and yeast that are regularly consumed along with your food can be quickly and easily dispensed with in a very acidic stomach, preventing what might otherwise become a short term bout of food poisoning or a possible longer term GI tract infection. Dilute all your meals with water, however, and the pH rises enough to possibly allow those same bacteria to pass through to the intestines where all hell can break loose. Literally.

Even cold and flu viruses that permeate the air around us are generally rendered harmless when they reach a normally acidic stomach, (after being breathed in and drained with mucous into the stomach). Drinking a ton of water all day long just might disarm that security measure as well.

Measuring Cup

So how much water does a person need? I think this question exemplifies our tendency to over-think many aspects of our health and well-being. I’ve mentioned on a number of occasions that animals seem to get along just fine on their own instinct. Do we really think we evolved any differently? Thirst is a physiological instinct that is there for a reason. Still, the makers of this bogus rule also tell us that the thirst instinct comes “too late”: we’re already on our way to dehydration once we get to that point! This is where the paleo-perspective comes in handy. Has our “defective” thirst instinct been leading us wrong – for tens of millions of years? I think you know where I stand on this one. So if you actually feel thirsty, by all means have a drink. For anyone interested in a little history of the rule (and confirmation that thirst doesn’t signal dehydration), check this (PDF) out.

Our individual need for water depends on numerous factors. Activity level, body size, environment (humidity level and altitude, most significantly), quality of health, age, and pregnancy/breastfeeding impose the most legitimate variations. In general, we want to replace the fluids we lose in a day, and intensive activity (with its accompanying sweat) will increase the amount of fluid we need. (For prolonged, intensive exercise and/or significant water intake, it’s essential to balance salt/electrolytes with water.) The drier our climate, the more water we tend to lose, but unless you’re sitting out in the blazing sun for hours at a time, it doesn’t make a huge difference. Altitude, because of the body’s more laborious breathing, can increase our need. Those who are ill can require more, depending on their condition and any treatments they’re receiving. (People with kidney disease, kidney stones, a history of bladder cancer, or a tendency for urinary tract infections are usually advised to drink more.) Women who are pregnant or nursing definitely need to drink more. Finally, I mention age not because older men and women necessarily need more water. In fact, if they’re more sedentary, they probably need less. However, some research has shown that as we age our thirst instinct may not be quite as sharp as it used to be.

For most of us, however, we can safely rely on that brain stem of ours to tell us when it’s time to belly up to the drinking fountain.

One final word on water intake:

Bottled water is a joke. If you don’t trust your tap, get a simple Reverse Osmosis filtering system.

Thanks for your questions, and keep ‘em coming!

massdistraction, Snap®, paulbence photography, phoosh Flickr Photos (CC)

Further Reading:

Water is Water is Water. Even When It’s Scam Water.

10 Ways to “Get Primal”

Would Grok Chow the Cheese Plate?

Subscribe to Mark’s Daily Apple feeds

Sponsor note:
This post was brought to you by the Damage Control Master Formula, independently proven as the most comprehensive high-potency antioxidant multivitamin available anywhere. With the highest antioxidant per dollar value and a complete anti-aging, stress, and cognition profile, the Master Formula is truly the only multivitamin supplement you will ever need. Toss out the drawers full of dozens of different supplements with questionable potency and efficacy and experience the proven Damage Control difference!

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

If you'd like to add an avatar to all of your comments click here!

121 thoughts on “Drink Less Water?”

Leave a Reply

Your email address will not be published. Required fields are marked *

  1. Thanks for the post mark, I especially like the last two points you made: water needs vary greatly upon numerous factors and $1.00/16 oz. of bottled water is a joke.

    1. I’m betting that all the sodium in modern diets is why we “need” all that water. it’s actually a fix to a problem w/ the modern diet. meanwhile, “drink when you’re thirsty”, which will be lots for some, and little for others, sure seems like pretty good advice.

      1. Listen to your body. Listen to your body. Your body speaks in feelings and desires. Listen to your body.

  2. GREAT post Mark.
    The little water I drink daily is to take your vitamins 😉

    Interesting tid bit;
    My 9 year old son plays roller hockey.
    When he comes of the “ice” on the bench all his team mates guzzle large containers of gatorade and water. For a while I kept on telling him to drink some water……because I never saw him really drinking. When I asked him about it he said he just wasn’t thirsty. I then realized that I’m the same way. But with all the coaches yelling “get some water” to the kids, I forgot that about myself. He is also the only really lean kid on the team.


    1. does your son eat the paleo way? I am wondering because I have a 10 year old daughter and I still give her whole grains. I fear that if I don’t she won’t grow properly or something. I’ve been fed to much healthy advise over the years and I just cant get over it. I still have this voice inside my head telling me that this might not be safe for kids.

      1. I recommend you to read “grain brain” by Dr Perlmutter, you will have a clearer perspective on whole grains and gluten.

  3. The past several weeks i’ve been snacking on watermelon. It quenches my thirst and i find myself not drinking water. Watermelon is my favorite summertime snack, it sure beats a glass of water when you’re thirsty on a hot day!

  4. I drink like a horse. Always have. I can put down 4 glasses of water with breakfast. Funny thing is, I never even bothered checking myself against an 8 glass a day rule. Never cared if I had too much or t0o little water. Water is water, right? Ah well, maybe I’ll cut back a little. Also, I’m a 250lb dude, so my water requirements might be on the high end.

  5. Couldn’t agree more with the joke that is bottled water! Imagine explaining this to someone in the 50’s…

    ME: Hey, Mr. 1950’s guy, I’m from the future.
    1950’s GUY: Swell. What’s it like.
    ME: Get this, there’s a coffee shop called Starbucks on every block of this city!
    1950’s GUY: Sounds great, how’s their pie?
    ME: No pie, just coffee.
    1950’s GUY: Good coffee?
    ME: Sure.
    1950’s GUY: How much does it cost?
    ME: Five dollars.
    1950’s GUY: …
    ME: …
    1950’s GUY: Wow, inflation sure is a mean devil. How much for frozen peas, 500 dollars?
    ME: 80 cents.
    1950’s GUY: Coffee costs six times more than peas! What if I don’t want coffee!
    ME: Simple, you can buy some water.
    1950’s GUY: …BUY water?
    ME: yep.
    1950’s GUY: How much does water cost?
    ME: Same as coffee.

  6. $5 for coffee? You’re right, that’s a good joke.

    An Americano is from $1.85 to $2.50 at Starbucks or just about anywhere else, depending on size and location (extra shots of espresso raise the price a bit).

    Americanos are shot(s) of espresso in hot water. I prefer an Americano to drip brewed coffee because it is freshly made for me, not pre-made and sitting around who knows how long. Espresso, even watered down, also tastes better than drip brewed coffee (especially old drip coffee) and has less caffeine.

  7. ..have a read about Lee and DeVores long term studies of the !San; also how they buggered up one group with bore holes thinking they were doing ’em a favour (thats a whole other eco-philisophical point that suggests we as a species are ttruly buggered.
    Also having spent a coupla years in Bots and Nam and seen these climes firt hand pre Nalgene..water was obviously scarce and they survived(or not) fine

  8. I pulled so many muscles during flag football one year because I drank too many liquids every day(100+ ounces of water, 8 cups of coffee, 4 beers). Bad stuff!

  9. Hallelujah! I thought I was the only person in the world who thinks that chugging water all day long is unnatural.

    To all the people who tell me that tea or coffee or fruit “doesn’t count”, I always ask them, “OK, how about if I swallowed a spoonful of coffee beans or the contents of a tea bag, and then drank a glass of water with it? You think that would be OK, right?” They usually don’t know how to answer that.

  10. Great post Mark.
    I would humbly agree on many points. The amount of water you take in should correlate to your activity level, your current state of fitness, and of course your dietary consumption (which includes all those wonderful processed and Sodium saturated foods)
    By the time your actually thirsty, it’s too late, your body’s h2O supply is depleted.
    I don’t think there is such a thing as drinking too much water. Your body can and does know how to handle the excess, but yes we should take into consideration how much at one time your consuming!
    Thanks for the great info as always.

    1. Just one question…How can a person’s water supply be depleted? Seeing that we are made up of more water than anything, we’d be dead if that were the case. I’m not sure I agree that 84 oz of water each day is bad for a person though. I have gotten myself up to that and once you start, it is quite easy. I’m sure it helps to keep up flushed out. If we ate healthy food, it wouldn’t be so necessary. Back when people ate meat, fruit and veggies and didn’t have processed foods, they probably got more water from their foods. Today, we have to flush the toxins out after eating the bad food choices all day. I agree that water is best drank throughout the day rather than with a meal. Interesting subject. Also, I find that when I do drink more water, I feel better, more alert and less bloating.

      1. Even a small decrease in hydration (2-3% if I recall correctly) has a marked, negative effect on performance. For most people, slight dehydration may not be an issue, but for athletes, proper hydration is key. This does not mean massive amounts of water, but water and nutrients when needed. Timing matters as well.

  11. I was wondering if the high grain and simple carb consumption in North America was in part to blame/explain the phenomenon of water bottling. When I was a kid, a million years ago, people just didn’t seem to require so much fluid. No one ever drank a litre of coffee in one shot.

    Maybe back then people didn’t eat like donkeys/horses/cows: grazing on carbs.

    I’ve done some reading on water recently. It seems that the North American ‘fad’ concerning ‘pure’ water is actually counterproductive. High calcium and magnesium levels in drinking water are associated with lower risk of sudden death from heart attack. So what’s the deal with all these near distilled waters? Those Europeans with their spas figured out something on an empirical basis: hard water is good for the body.

  12. I really agree with this and I’m glad it’s been posted.

    Whenever someone tells me that by the time I’m thirsty I’m dehydrated, I just reply that it’s careless of Mother Nature to have messed up such a basic feedback mechanism so badly.

    Here’s another link along the same lines: https://tinyurl.com/zwc

    And it’s easy to spend $5 for the fancy coffee-based drinks, which is presumably what the previous poster had in mind.

  13. I’ll just throw in that I used to drink water all day long (probably close to a gallon), was quite literally a stick, and ate a bowl of oatmeal a day as about the only consistently eaten carbohydrate. I get thirsty very easily and I hate the feeling of having a dry mouth. So the more filtered tap water, the better.

    1. That just goes to show that everybody is different and that no health industry should “force” people to consume the same amount of water in order to be classified as “healthy.” The health industry needs to take into account that God created us differently. This whole “be healthy” movement is counteractive because it is stressing out citizens “including myself.” We as humans need to just trust God in everything and ought not worry about anything.

      1. I agree, i grew up in a difficult home, we never were told about taking care of our heath…we were kids. I came from 2 generations of smokers. I started smoking at 17. I drank coffee, ate reasonably well…had my share of the drugs and bar scene. Left my mid 20’s with alot of painfully stuffed emotions. Information health started popping up all over. All of the sudden you are faced with oh my God…i need to take care of my health. Meanwhile, the stress came from the thought, because now we find ourselves focusing on the problem, where there was no problem, which seems to escalate…makes you wonder…is this all in my mind?

  14. Dr. Gabe Mirkin has an interesting post that implies that professional bike racers have better kidney function because they often become dehydrated. Here’s a partial quote: “The researchers found that frequent dehydration accompanied by drinking large amounts of water did not cause kidney damage. This repeated stress on the kidneys may even explain why the professional cyclists had better kidney function than the less-active participants.” https://www.drmirkin.com/public/ezine051808.html

    1. Long amounts of sitting can compromise kidney function through lack of blood flow.

  15. Good article, in fact you’ve stated something I’ve often thought about myself. I just don’t seem to need 8 glasses a day.

    I used to live in Oman & Quatar, in the middle of the desert (when I was younger) and even back then, in 40 – 50 degrees heat, I didn’t seem to need the full 8 glasses of water a day.

    Now I’m in the UK and I drink perhaps 4 glasses a day max. I do have a very healthy diet though. Whilst I think this conventional wisdom isn’t a bad thing, I also think its importance has been overstated and if you just drink when you are thirsty you’ll be fine.

  16. My believe is that there is such a thing as drinking “too much” water. I use to drink way too much. Years ago I followed advice from a very wise man to drink way less and i noticed how much better i felt!!! Drinking “too much” water is NOT healthy!

    1. Donna, this is interesting. Would you mind explaining more? I grew up watching my mom carry her glass of water around everywhere and now I do the same. I easily drink 2 gallons a day because I simply feel a little thirsty all the time. I also pee a ton. It’s a little annoying but I figure if I am thirsty I should drink. Maybe I am compensating for something else. Maybe it’s the minerals I want? Maybe I am being hyper sensitive and I can train my body to need less like you did. I am not even THAT active anymore. I don’t drink much alcohol or coffee because that seriously exacerbates the problem! Anyway- I wonder what is going on

  17. I’m like Lou. I just drink a ton of fluids. Always seemed to be that way. I have a liter in the morning with breakfast and on the ride to work. Then couple cups of dark roast and then water the rest of the day. Especially with my meals!? If its dinner I will go through a couple pints of ice water no problem. If it’s iced tea when my parents are in. It’s at least four pints. No sugar though. When I’m working out riding more so than when I lift, I go through water quick also.

    Now its all unhealthy 🙁 Hopefully the effects aren’t too detrimental because for the most part I’m just thristy not actively trying to get my eight glasses.

    If you think $1/16oz is bad (and I hate buying water because its silly and the waste), I just got back from my honeymoon in Italy where at the most expensive we had 3 bottles of Pellegrino with one dinner for 5euro each for less than 700ml. Of course the won’t give you tap water. It was about 15 euros for 2L of water. Don’t do the exchange rate conversion it will make you sick.

  18. Uh-oh…I think I’m In trouble…..well, not really. But I have always been constantly thirsty. I don’t care about the 8 glasses thing,I just drink when I’m thirsty.ever since I can remember I wanted water all the time. I always keep a big , glass juice bottle with me filled with filtered tap water and I drink anywhewre from 2 quarts to 2 gallons in a day, depending on the day. I’m extremely active and I talk alot( this is what my mother blames). But if I don’t drink when I’m thirsty I get a migraine. The water rule is silly because every person is different, we’re all an experiment of one.

  19. Really interesting concept. I’ve never come close to meeting the water recommendations (even the old 8 glasses of water a day one was too much, let alone the newer ones, which I think are at least 91 ounces for women and 125 ounces for men), but it’s always something I’ve worried about in terms of sports performance. What do you make of the studies that show performance is affected when you’ve lost even 2 percent of your body weight due to dehydration?

  20. JenS,

    Of course working out hard and long changes everything. It’s an unnatural act that requires an unnatural compensatory act (drinking more than you otherwise might). training and racing in the heat without water is suicide (figuratively if not literally). I lost 12 pounds running my first Boston Marathon in hot temps at age 20 (144 to 132). Stupid now, but we didn’t know better 35 years ago.

  21. You start off so well offering evidence-based debunking of a common myth. Then you go on to offer new myths that have no evidence to back them up or are entirely wrong.It seems you employ the same level of evidence to draw your conclusions that you point out initially as being faulty.

    You define hyponatremia as a reduction in all important electrolytes, it only refers to lowering of sodium levels in the blood. The closest word to your definition would be hypo-osmolality. You probably overestimate the risk of water intoxication for a healthy adult. Their intake must excede their ability to excrete water, which is about 900 ml/hr. You can do it, but it requires effort. It is rare enough that when someone pulls it off they often make the news.

    What evidence is there that 8 oz of water at a meal will “substantially dilute the stomach acid”? Ph is a logarithmic scale. To get from 1 to 3 requires a 100 fold dilution. Even if you assume a minimal volume of acid in the stomach, say 25 ml, you’d be talking about chugging about 2.5 liters to get to pH 3, which is still adequately acidic. A large meal accomplishes this shift…for maybe a minute. On what basis do you conclude that water is even more effective at doing this. Rising to 3 or 4 during a meal has no effect on effectiveness of digestion so how are you able to conclude that a glass of water with a meal will “diminish its ability to digest your food.”

    You offer a guess that many cases of GERD are caused by water intake. So now you are speculating that somehow drinking water contributes to lower esophageal sphincter incompetence. How do you guess that water causes this localized muscular dysfunction? By slightly diluting stomach acid? This seems like either wild speculation or a very uneducated guess by someone who is presenting themselves as quite learned on this topic.

    What evidence is there that wine’s effects on digestion are pH related? (none) Ah, but there is something that can effect esophageal sphincter tone!

    What evidence is there that the tiny fluctuation in stomach pH from drinking water or for that matter the larger fluctuation associated with food intake effect the antibacterial effectiveness of the stomach? (none)

    What evidence is there that the tiny fluctuation in stomach pH from drinking water or for that matter the larger fluctuation associated with food intake effect the digestion of proteins in such a way that would effect immune response/allergies? (none)

    In fact most theories of incomplete protein digestion triggering food allergies relate to the infant’s gut where gaps exit for undigested/ partially digested proteins to access the bloodstream and not to the adult gut.

    Infectious agents that spread through ingestion and effect the gut are, not surprisingly adapted to the acid environment and not contracted due to an elevation of gut pH.

    Cold and flu viruses are adapted to respiratory cells (the flu is a respiratory illness and not a GI illness, though some people call that “flu”). If they survive the acid environment of the stomach, they are unlikely to find respiratory cells beyond there in the gut. Some respiratory pathogens can cause significant problems elsewhere (TB for example) and stomach acid may have some effect when those pathogens are swallowed.

    I think it is great that you look critically at common conclusions based on shaky evidence or evidence that has been misinterpreted. However, to debunk 1 and then offer 7 or 8 new conclusions based on no evidence or on faulty understandings of GI function and pathology seems to pretty much destroy the whole point that you started off making…unless this was a clever exercise to see how many people noticed that you debunked one common misperception only to repeatedly make the same mistake that created the need for debunking in the first place. If that is the case, then Bravo! Well done!

    1. I applaud you. I mean, Mark has some good points, but I find some of his claims extreme. You make excellent points. I know when I fail to drink at least 8 cups of water I get tired, cranky, and everything goes downhill. With water, I eat less, I have more energy, and I feel better. And I tested this, I did 4 days of drinking water when I felt like it, and today was the 5th day and in the morning I woke up with a nasty headache (like i did for the past 2 days) and I was sluggish, and cranky… Then I drank some water in the late afternoon, and I had a surge of energy and my moods lifted.
      Drink less water = bad mojo for me. So for Mark to tell people that drinking 8 cups of water to be healthy is a “myth” is misinformation. Because I know that when I drink 6-8 cups of water a day I feel my best, and actually my digestion goes a lot smoother, eating the same things I do with water being the only variable. I turn into a monster when I only go by drinking when I feel like it. The fatigue is unbearable by the way… I sat all day and felt exhausted like I ran a marathon, when I spent the whole day sitting… And I’m a long distance runner and I was about to trip over myself running a mile (and I had a nice 3 days of doing nothing!).
      Sorry Mark, not one of your strongest articles.

    2. If you want your viewpoint to be taken seriously, you need to learn the difference between the words “effect” and “affect”.

  22. Arjuna,

    First off, thanks for your very detailed and thoughtful comment. I appreciate that you took the time to address this so thoroughly.

    Your points are well-taken, but I think I was quite clear that I was not offering conclusions. I was looking at a lifestyle that assumed “more water is better” and from there, speculated what might be happening in some cases. I sprinkled terms like “I suspect”, “I would guess”, “might explain”, “possibly” in reference to “a ton of water”,”lots of fluid” or “dilute every meal.”

    I never sugested that “8 ounces with a meal” could disrupt digestion for everyone or anyone. I was suggesting that maybe someone who has partial hypochlorhydria already or a stomach pH of 3-4 or is taking PPIs can easily cross the line with excessive water consumption. From there I offered some possible health scenarios. Some may appear a little far-fetched from a traditional AMA POV, but that’s what opens the door to discussion. If we want to start more serious debate on “evidence for immune responses”, we’d have to agree that evidence exists to suport both sides of the issue…as happens so often in medicine. If there were a right answer, everyone would agree.

    As I state here often, my posts are representative of a primal point of view. I look at how we live and then suggest ways we might be thwarting our “evolved design”. I certainly use this site as an evolving wiki for my own POV and encourage people to speak up as you have. Your input today helps with that.

    Hope to hear more from you.

  23. Mark,

    Thanks for your reply.

    I think that you may have missed the main point of my comment. The point was that you hold those you disagree with to a higher standard than you apply to your own writing. I saw all the “I suspect”, “I would guess”, etc. I’m sure you know that all those phrases can be summed up in one category. They are called “weasel words” because they are often used to precede an opinion for which the author has no foundation. Many people who are familiar with logic and critical thinking will recognize all the weasel words and discount what you are writing but there are still many who are swayed by them or unaware that they signal faulty arguments. So, if I understand correctly, you admit there is no basis for your assertions but feel they are OK to disseminate as long as you include the weasel words?

    The point was that you noted that those who recommend 64 oz of water a day have no basis for that opinion so it shouldn’t be heeded. I agree. A strong secondary point to your opening is that we should critically examine claims from all sides. Again, I am in complete agreement! You then offered your own unfounded opinions, admittedly surrounded by weasel words.

    I also completely missed where you qualified that you were offering an opinion about people with pre-existing achlorhydria or those taking PPIs. Unfortunately, I’m still unable to locate that in your original post. Could you quote it for me?

    In fact you said, “When you drink lots of fluid at a meal, you are substantially diluting the stomach acid and diminishing its ability to effectively digest your food. ” This proverbial “you” surely sounds like the statement is a general proclamation. It certainly doesn’t say “when you people with achlorhydria” or when you people taking PPIs”. Maybe you meant to add that qualification but forgot. If so, it would be appropriate to edit your post for future readers and even possibly change the title to indicate the narrow application of the opinions you are offering. Other commenters could certainly weigh in on their reading of the post but I don’t see anything that suggests this qualification.

    You go on to suggest that whatever we may disagree about bears some relation to “Primal POV” vs “traditional AMA POV”. First, thank you for assigning me a point of view. I’m not sure you know me well enough to do that. This logical fallacy is currently very in vogue, what with Fox News and all the science deniers who claim that misinterpreting climate science is just a different POV. I must admit it can be frustrating when someone attempts to skirt the factual and logical issues being raised by assigning someone else a point of view and attributing the difference to that. I don’t think the existence of hydrogen ions, the logarithmic nature of the pH scale, or the defect that underlies GERD, as examples, represent any particular POV. There is evidence to support these facts.

    Same with the issue of immune responses. Scientists understand how to weight data and critically assess the relative value of studies. Understanding the scientific process they understand that for a variety of reasons there will be data on both sides of any issue. The problem arises when the value of the data is not examined and we believe that having some data that contradicts the mass of good data means the good data is wrong. Again, please see the climate change debate. This basic misunderstanding of science is used constantly to suggest that issues for which we have a preponderence of good evidence are “unsettled”.

    I appreciate that your intention is positive and you hope to inform people on healthy living. I appreciate your attempts to debunk unfounded assertions such as high water intake. It is an admirable endevour and a serious one. I only hope that you will apply the same standard to your own assertions. A good place to start might be that if you really want to educate people then if you feel you need weasel words to qualify your statement, leave that statement out.

    1. I’d like to point out that Mark said this is my personal hypothesis. You know what a hypothesis is, right? Speculation is the foundation of science. Mark goes on to speculate on some of the ramifications of this hypothesis. Hence these aren’t ‘weasel words’. I find his speculation credible and interesting.

      Without hypotheses, one cannot proceed to theories by applying the scientific method. A hypothesis (drinking too much water might lower stomach pH) can then be tested by making a prediction (people who drink lots of water have a higher incidence of prandially acquired disease) and testing it in a controlled manner.

      The internet has turned everyone into an expert on logical fallacies, but of course the majority of people don’t really understand them. It’s the logical fallacy fallacy.

      1. Only he said drinking lots of water would dilute the acid. If it lowered the pH, that would mean water makes it MORE acidic.

  24. Arjuna,

    You are aware that this is a BLOG, are you not? Do you understand that a blog is not held to the same standards as, say, a medical journal?

    As Mark states in his disclaimer:

    The views expressed on this site are my opinions. My words or any contributions from my staff should not be taken as a substitute for qualified medical expertise. I don’t really censor Aaron or Sara or the rest of my staff (though I do review all their contributions).

    So, while I’m a “health guy” with a biology degree and many years of fitness, health and nutrition experience to my credit, my views are just that – my views. I hope you’ll find the blog to be helpful, challenging, engaging and compelling.

    I, for one, am really enjoying his thoughts on the subject, even as unbacked by medical research as they may be.

  25. Arjuna,

    I’m afraid we are getting bogged down in minutiae here. You call them “weasel words”. I call them disclaimers. You argue that I assigned you an AMA POV; I didn’t. I just acknowledged that from that POV, my ideas might seem unique.

    You argue:”I don’t think the existence of hydrogen ions, the logarithmic nature of the pH scale, or the defect that underlies GERD, as examples, represent any particular POV. There is evidence to support these facts.” and yet you lump these all into a category of facts (the very same approach you accuse me of doing) when the so-called “defect” that underlies GERD is not known for certain in all cases(ie, is not a fact). There are many known and/or suspected causes of GERD and many can be eliminated with simple lifestyle change. Maybe less water at meals is one. While you argue that I shouldn’t suggest copious water at a meal is a possible cause, you can’t say for sure that it’s not.

    Anyway, let’s agree to disagree on these points and move on.

  26. I apologize dragonmamma. I realize it is a blog but didn’t realize that implied that false information was on the menu. Thank you for clarifying that for me. You apparently found something in that disclaimer that implied that false information should not be pointed out or challenged. I didn’t. That may be my mistake.

    Some people do care if the health information they consume is true. I can see that for you it is most important that it is “enjoyable”. I didn’t mean to offend your sensibilities. I agree with you that the writing here is enjoyable. We just have a disagreement about whether truth is also an important aspect of health information. Enjoyable writing that is not true is called fiction. If this blog is fiction, I hope it would be labeled someplace as fiction. Then I could have avoided displeasing you.

    It appeared to be non-fiction. It had a comment section, which I assumed was for comments. The author seems capable of a civil discussion. I discussed. Sorry if that went against policy.

    If your criteria for useful health information is the enjoyment that you receive from it then I wouldn’t think it would serve you to join a conversation on whether or not it is true information. Why not just continue to enjoy?

  27. Sorry to interrupt, but…can anyone explain more about balancing salt/electrolytes with water after heavy exercise? After training I normally drain a water bottle pretty fast but never think about replacing salts.

  28. You took then words right out of my mouth its true the more I drink water the easier it gets but my natural instinct is not to drink water.I could never figure out how water was doing me any good because within five to ten minutes after drinking I need to urinate and its always pure water it seems to me if you get your water with food it would take longer to digest therefore doing more good.Also I would like for you to talk about potassium I think this is far more important two years ago I was swelling.deoressed,almost passing out when I would get up and worst of all my legs would feel like they were crawling all the time I also have been running for many years and never supplementing but not one of my doctors that I went to told me to take potassium in fact one doctor gave me a prescription for restless leg syndrome but even it persisted I finally started doing some research and found that we actually need 4500 milligrams of potassium per day so I tried it all my symptoms went away and know I know when my body screams for potassium.Thank you for helping us fix things without making it be about popping pills.

  29. Hey Mark

    What a post to get my mom to read. She always asks “Did u drink water?”. At tims I use to wonder if that was true about 8 glases. This post is a great way to look at th 8 glasses in a day.

  30. You touched on the grains sopping up water, but have you put any thought into the water that we intentionally cook out of our food? Mainly fresh living/raw fruits and vegetables. Did Grok cook the fruit he would find? Would you eat the orange? Or, would you burn it first?

  31. Just curious, I have always just my water consumption on the color of my urine. It’s been darker lately since I have mainly been drinking tea and only water when I am thristy. Does this darker color have anything to do with my health? Does it make a difference?

  32. Cara,

    I don’t think the color of your urine has anything to do with your health in general (unless you had just finished a marathon and were urinating “coke-colored”). Otherwise, just let your thirst be your guide. And that doesn’t mean you can’t enjoy a spot of tea even when you’re NOT thirsty!

  33. Mark,

    Just as a note, I thought I could interest you in a post that I recently read from Lifehacker. It was a note that the BMJ tried to debunk a few medical myths. One that caught my eye was the fact that everyone should drink 8 glasses of water daily. I thought I would paste the relevant text here to save you some time:

    As taken from https://www.bmj.com/cgi/content/full/335/7633/1288:

    “The advice to drink at least eight glasses of water a day can be found throughout the popular press. One origin may be a 1945 recommendation that stated: A suitable allowance of water for adults is 2.5 litres daily in most instances. An ordinary standard for diverse persons is 1 millilitre for each calorie of food. Most of this quantity is contained in prepared foods. If the last, crucial sentence is ignored, the statement could be interpreted as instruction to drink eight glasses of water a day.

    Another endorsement may have come from a prominent nutritionist, Frederick Stare, who once recommended, without references, the consumption “around 6 to 8 glasses per 24 hours,” which could be “in the form of coffee, tea, milk, soft drinks, beer, etc.” The complete lack of evidence supporting the recommendation to drink six to eight glasses of water a day is exhaustively catalogued in an invited review by Heinz Valtin in the American Journal of Physiology.

    Furthermore, existing studies suggest that adequate fluid intake is usually met through typical daily consumption of juice, milk, and even caffeinated drinks. In contrast, drinking excess amounts of water can be dangerous, resulting in water intoxication, hyponatraemia, and even death.”

    Although I may not agree fully, I believe this will help your argument.

    Your Digital Trainer,

    Jeremiah Bell

  34. I’ve been looking for this post since June 2008 and I FINALLY FOUND IT!

    I’ve been telling my coworkers they really need to cut back on the water, mainly because it’s silly to pay for it and because we have a delicious water fountain and the tap tastes like lead pipes and rocks. They all seem to be stuck on the RDA of 6 to 8 a day; they’re also mostly overweight, have mobility issues and a constant case of bad breath and or a whiff of body odor when the temp is high enough to promote a bead of sweat. I attribute a lot of this to the overzealous water intake and inadequate “healthy” food ingestion.
    I’m an enigma to most because they rarely see me consume water (and I can “not eat” for days)…but can always count on me having my coffee, juice or tea, a salad or any type veggie cooked or raw and yogurt or on occasion rice. I’ve NEVER had acne or skin problems, and although I find it difficult to gain weight I haven’t changed that much since high school- can even still wear some of the clothes. As well, I’ve been known to “reject” water; ran track and cross country in HS and water always came back up so I’d take minuscule sips (like Grok) or not at all, the hotter it is the less I want to drink. I don’t sweat profusely, nor do I have issues with BO…again, not so with my “camelesque” (no pun but it could easily fit) counterparts. Am I truly an enigma or am I just happily following my primal instinct and letting my body tell me what it needs?

  35. I wrote my master’s thesis on water consumption, and he’s right that the 8 glasses of water a day is a misinterpreted piece of data that stuck. There is a big difference between glasses of water and your total water consumption (which includes consumption from food).

    The amount of water you need varies by person. I am a runner who lives in the Sonoran Desert and has urinary issues that are assuaged with drinking lots of water, so I actually drink at least 6-8 glasses a day. But I’d never suggest that other people do the same thing.

  36. Times are a changin’ and so should our outlook on ALL aspects of life. We are and have been for a hundred years or so, a re-thinking world. What was rule even a couple years ago may very well be proved drool as of yesterday. Science is everything but ever changing so never become so dead set as to cancel out anything 100%.
    That being said, how the heck did you ever feel that a quality comparison of us as human beings, living in the enviroment that we do, should rely on what Grok did as “makes sense”
    Pardon my ridicule but come on! Grok didn’t need much water so we don’t either. I won’t even get into a heated and extremely educational debate over this but I really enjoyed reading the previous one. However, your statement is as wide open for trouncing as I have ever seen. How about this one…” Grok was never seen filling his gas guzzleling Escalade up with Premium Unleaded fuel”
    Times are a changin’ and thanks to people such as yourself, so are opinions but lets try not to slay the dragons with swords dull as bricks.
    By the way, if you think water is water is water…you have never seen the effects of a rain storm on all things growing compared to the constant yet inadequate watering using an irrigation system on city water…Miraculous is the difference ! Have an awesome day.

  37. But your primal diet makes me soooooo thirsty!! I crave cruciferous veggies too!

  38. Coming back to the points raised by Arjuna: I appreciate much of what i read in this blog, but i always make an effort to cross-check. In this case, i read the pdf reporting the study on the 8by8 “myth” and found *that* rather skewed in its interpretation! What stroke me most was the discussion of the danger of ingesting too much water. It reported 3 cases of death and attributed them to water, when it was clear that in all cases, it was not the water causing the death, but the simultaneous ingestion of antidiuretic drugs (once a medicine, twice extasy). While this is clear from the text, the way it is reported seems to imply that too much water can be dangerous in general, while the real conclusion is: extasy messes up with your body and its signals and mechanisms! (so do most pharmaceuticals, by the way)
    Regarding thirst, i am a low drinker, and am never thirsty, but i have to admit that whenever i take the “drink 2-3 liters of water” prescription seriously and make a point of drinking more, after 2-3 days i start to be thirsty much more often, and to want to drink more, and i feel much better in terms of energy level and mental clarity. I have also found out that drinking one liter when i have a headache makes it go away. And the point raised about eating coffee beans and drinking water separately and most people not being able to react to that: obviously Dragonmamma only talks to slow or superficial thinkers, because it is clear that the problem is the diuretic effect of caffeine, not of “coffee”: so, eating coffee beans may or may not be problematic, to the extent that caffeine can be absorbed by the digestive system without having been extracted and made available by steaming, boiling or filtering. If the absorption from beans is the same as that from coffee, then obviously the reply is: yes, it would be exactly the same as drinking coffee, and you should drink as much extra pure water as it takes to compensate for the caffeine intake.
    To paraphrase Nike: *just think!*.
    My conclusion is that yes, i agree with Mark that our evolution has equipped us with all mechanisms that will let us know when we need more water, *but* our current lifestyle, with unnatural food, medicines and other chemicals, unnatural schedules etc, may mess up with those mechanisms. We are not as instinctual needs and connected with our body as wild animals any more: we have become like those domestic cats who will only eat fish when it is cooked and will even eat carbohydrate-rich sweets! So no, we cannot trust the signals from our brain stem, unless we are *clean*.
    I think Arjuna is right, in pointing out that we should make a much bigger effort to evaluate all the evidence, both analytically and by personal experimentation. And only communicate what we are reasonably confident about.

  39. Started drinking more water than ever about 2 mos ago. Within the last week discovered I have GERD/Acid Reflux. Thought maybe the acid in the water was the issue. Maybe it’s just the excessive consumption…needless to say will be backing off!

  40. I drink water when I’m thirsty, end of discussion. In the winter, this can equate into a cup or two per day. I’ve never had problems with dehydration; my urine remains a healthy yellowish color.

    In the summer, of course, I need more water, but drinking it plain doesn’t always help – I get sick of the stuff and still feel thirsty – so I supplement with cucumbers.

  41. As a practitioner of Chinese medicine I have an opinion about anything that “everyone” should do. As I see it, we are all wildly unique individuals. Yes, there is a “blueprint”, but the differences are significant.

    Who should drink a lot of water? Those with a “dry” constitution. Or those who tend to process their fluids quickly. For many of us, drinking too much water leads to digestive problems which (guess what) leads to weight accumulation.

  42. Gotta agree with Michael on this one.

    I’ve always been a thirsty guy. My son is the same way. I’ve never drank water just for the sake of it, but because I get parched fairly often. I also do very difficult workouts so I sweat a lot. I know, I know…not very Primal of me. I just like pushing myself–always have.

    I actually went in for some tests last year due to a kidney injury and discovered that I am a naturally dry person. So it made a lot of sense that I drink water often. I was doing it because my body was telling me I needed it. Does everyone need to drink 8 glasses of water per day? Probably not. But I know the Primal approach towards water isn’t the right one for me.

    Interesting reading though…and certainly makes you wonder about some of it.

    1. The Primal approach *IS* listening to your body and drinking what you need…

  43. A friend of the family drank in excess of two gallons of water per day. Making it more dangerous, was that she weighed less then 100 pounds. While driving, she had a seizure and smashed the car into a lightpost. Blood tests were done and showed that her electrolytes were nearly to the point of non-existance, causing the seizure. The doctor told her to stop drinking so much water and start eating food. Luckily, she didn’t kill anyone.

  44. IMO if you’re thirsty then it’s too late. Staying hydrated also does wonders for your joints since places like tendons don’t get as much blood flow as your muscles.

  45. Everything in balance. Do we need water regularly? Yes. Do some people need more than others? Yes. Did Grok have more nourishing food, plants and fruits with higher water and noutrient concentrations? Probably. So he could get a lot more water from his food. (I don’t buy the argument that modern wo/man gets all he/she needs from his/her food. We live in a fast-paced society where most people are eating non-organic processed foods…it would be wise for those folks to drink water throughout their day. 6 glasses, 8 glasses…whatever. It really isn’t that hard to drink 8 cups of water a day, but if you feel you don’t quite need that much…no problem. I will say that I know from personal experience that you CAN drink too much water all at once. I have known two people who have done that and put themselves in the hospital. Like someone said earlier, there is a level at which your body can’t process all the water that is put into it at one time and it will make you pass out, ill or even kill you. But this level is pretty high, Two gallons of water a for your average person is definitely too much. But I drank a about a gallon a day while pregnant with twins and felt great. I don’t remember the amount my friend drank. One friend did it to be macho (pretty dumb in my book) The other friend was actually in a bike marathon and she was drinking nothing but water and not putting enough salt/electrolytes back into her system. Balance is key. If you consistently deprive your body of water it is possible that you will throw off your feedback mechanism and then drinking more water will cause you to get thirsty more often basically resetting your feedback mechanism. But it really does depend on the person and their level of physical activity, where they live and their body type.

  46. I’m not going to try to get into any debates here, just wanted to throw in my own experience. I’ve always noticed that I performed and felt better when drinking more water throughout the day. I actually used to drink a gallon a day and felt pretty damn good when I did.

  47. Bottled water IS a joke! I collect spring water now. I am not sure it is much better for me, but it tastes better and there is a less likely chance it contains chlorine. I LOVE your site btw!

  48. i think 8 glasses/day is a stupid, one-size-fits-all advice.

    I’m a small: 159 cm & 46 kg (102 lb for you guys)

    when i used to drink 8 glasses/day (in addition to meals, coffee/tea/fruits like what they told u); the result was i just lived on the toilet & i felt bloated a lot.

    really no fun, especially, getting up every 20-25 min in the swimming pool; getting up 3-5 times/night, stopping for bathroom every 1 hr during travel by car/airplane. it also made me feel cold all the time

    now i only drink when i’m thirty. that means about 1000 ml (~ 4 cups/day), 1/2 of what is recommended.

    there is no sign of dehydration (from the urine color).

    + i sleep so much better.


  49. how can the water bottle companies go wrong , by selling water more expensive than gas, and we watch the gas prices like vrazy, but we never complain about the prices of water, though it costs much , much less to produce. in islam there is a rule that says one third of your stomach is for food, the second is for water , and the third is for air; breathing, my allah bless all of us.

  50. Eight cups of water per day is a lie like everything else in mainstream America. I drink a pint per day if I’m vigilant about it, and that’s living in central FL.

    May Allah remove Himself from this blog, by the way.

  51. THAT WAS FUN…I am writing a post on water and Diabetes for my blog “Tribal Diabetics.com” I thought…”First let me slide over to Marks Daily Apple. I know there must be great articles to cite and then I will pass the links on to my readers to follow up in Mark’s world.” Then I read all the comments and I was all up in the battles of Arjuna. Man, I really feel dumb for not coming up with one of his points on the proper “truths”.

    I am going to hustle right now to find his health blog where he is part of the solution instead of part of the problem. Uh oh, can’t find it. Can Arjuna find me and lead me to the promised land? He is brave, I will give him that, to wander into what he knows will be a hostile world. However Arjuna, it is easy to shoot from the dark recesses of the audience and much harder to shoot back with all the stage lights of the world in your eyes. Put the lights on yourself, as Mark and myself have done, by posting your own blog. Be part of the solution and not part of the problem.

  52. Re: GERD (or heartburn), the best theory I’ve read is Norm Robillard’s. He hypothesizes that carbohydrates create gas when they’re digested and the gas pushes up the contents of the stomach. In people with a weak lower esophageal sphincter muscle, this results in heartburn. It seems to me if you’re drinking a lot of water, there are more contents in your stomach and they’re more likely to reach the LES. (And according to our friend Arjuna, the water won’t alter stomach pH much.) So possibly, guzzling water could contribute to GERD. Hope that isn’t too weasel-y. 😉

  53. I’m sorry but a blog like this is FAR more likely to kill somebody than drinking 8 cups of water per day… or 30 cups for that matter.

  54. I like Arjuna’s comments and questioning of Marks post, and am disappointed by some people immediatley posting that it is a blog to try and squash her points.Blog or not, facts should not just be thrown out the window because it can be calssified as someones opinion.She questioned him in a civil manner, and the more civil opinions the better.

    Bottled water? It is what it is.It is a great convenient way for people to drink water when they are on the go.It can be had *alot* cheaper than some here claim-ie “several dollars per gallon”.I’d much rather drink it than the city water with chemical sterilizers, chlorine,lead, and UNnatural fluoride in it.The same water that is piped through plastic piping in modern buildings, through leaded pipe and leaded solder joints in older buildings as well.

    As for how much water….simple, drink enough so that your pee is very light yellow.Dark amber pee is a sign you are not hydrated and your body needs to work that much harder to expel waste.Pee that is the color of water is not needed, and probably makes your body work just as hard getting rid of excess water.

  55. Thirsty person here, too. I used to get horrible headaches in high school, and after some conversations with my mom, she recalled an article about drinking water and asked how much I drank during the day. I was maybe having a drink with lunch and that would be about it.

    Started carrying a bottle around with me in high school and I haven’t stopped. I drink quite a bit more than average (I’d guess that I fill a 32-oz Nalgene bottle 6 or 7 times over the course of a day).

    I notice a very direct cause and effect when I’m unable to drink the right amount for me – my body will feel more “tight” and “tense” (for lack of a better term) and if I go more than a few (waking) hours, I’ll get a headache. For me, headaches are an extremely rare thing because I’ve been able to identify dehydration as one trigger – and that’s very easy to deal with.

    As for bottled water … it’s a rare thing for me to drink it. When I am in situations where I need to buy it, I’ll buy 1- or 2-gallon containers and fill my Nalgene from them. Cheaper and significantly less wasteful than single-serve bottles.

  56. Damn, i have been a slave to the whole “1-2 gallons of water every day” myth since i got into bodybuilding several years ago. Any kind of bodybuilding is LONG behind me, but i still continue to chug water on a daily basis, with meals as well. Now that you mention it, i can’t help but think this might be a cause for my GERD! Im gonna try to stop drinking so much dang water and see what happens, but im pretty confident this will solve it. Great article Mark.

  57. Love that you have the balls to say these kinds of things.

    I’ve been telling my health conscious friends this for years as they accuse me of being dehydrated and of dehydrating my son because I don’t force-feed tons of water down his throat. We get plenty in our normal day drinking and foods.

    I do occasionally feel thirsty..and when I do…I DRINK some water!

    It’s not rocket science..I believe our bodies will tell us when they’re in need of something. (and I’ve always tended be be healthier than my water-chugging friends)

    Also, good call on bottled water.
    Why pay for something that’s running out your faucet…and it’s an environmental nightmare. The oil needed for the bottle and for shipping this heavy stuff is 100% waste.

  58. I am glad you mentioned that the amount of water needed could be based on the actual foods we eat. I have often wondered if the amount of sodium in one’s diet could contribute to the need for water (or lack thereof). Back in Florida, where the humidity is so high I felt like I needed gills, I also had a very low-salt diet. I didn’t cook with it or anything. Interestingly, at that time, I HATED drinking water. Once I moved out west, with the drier air, I wanted it more. Even in Washington, where I live now, I still like water a little more than I did in Florida (but I still have a hard time with 8 glasses a day, or 1/2 oz for every pound of body weight).

    I would also like to know how to replace salts after strenuous activity. My body’s air conditioning works very well (i.e. I sweat a lot) when I exercise. My endurance is higher than many people’s, but I also need to replenish. I drink water because i want to avoid those disgusting sugar-water drinks. But how do I replace potassium and other salts (without ridiculously high-carb options like bananas)?


  59. Dear Mark,

    I’ve been trying to research for the amount of water we should drink per day until I read your blog.
    The reason for my research is that, I’m visiting one Chinese Doctor( Chinese traditional way of healing ) and the doctor let me drink one Chinese Herbal medicine and inform me that I should drink very less water in one day.
    The thought of drinking less water is quite new and strange to me, cos I’ve been told from everywhere that we need to drink at least 6 to eight glasses of water per day.
    Anyway, I ask the doctor for the reason of it. His answer is quite similar to your blog. He said that in our daily meals, there’s water every where. We actually don’t need to drink more water. Too much water in our system will be harmful not helpful.
    He advise that we should be very careful with what we eat. In Chinese ways food are divided into two categories, the Yin and Yang. Yin is cold substance and Yang is hot substance. We should try to balance our dietary between Yin and Yang.
    Today is the tenth day I am trying to practice his eating concept. I found out that I actually don’t feel too thirsty even I don’t drink water the whole day.

  60. Mark,

    You are completely delusional in thinking that this is a healthy recommendation at any level. Whether it’s for a triathlete, a body builder, or a kid playing baseball at the neighborhood park, we all need at least this recommended intake of water…unless you are ok with being an average subspecies at any sport or whatever you do in life, best of luck.


  61. Throughout the awesome pattern of things you actually receive an A just for effort. Where you actually lost us was first on your particulars. As it is said, the devil is in the details… And that couldn’t be more accurate at this point. Having said that, allow me inform you what exactly did give good results. The writing is incredibly powerful and that is most likely why I am making the effort to comment. I do not really make it a regular habit of doing that. Second, while I can certainly see the jumps in logic you make, I am definitely not confident of how you seem to connect your ideas which in turn make the actual conclusion. For now I shall yield to your point however hope in the future you actually link your dots much better.

  62. Okay, I definitely see the point of both sides, those who say consume and those who say don’t consume much water. My best advice to people is to just take both sides with a grain of salt. Do everything in moderation. No one is God and knows the absolute truth about anything. Evidence is just statistical data that suggests an explanation. We as humans, just use our 5 senses to make sense of the world, but God could easily turn the tables on our “factual data.” We just have a human perception of the world. Now, I might seem contradictory because you might say “Well, your believing the Bible (the inspired word of God) to be absolute truth,” but believe me, no one wants to reckon with God. He loves us; he is also a just and fair God (he must punish us for our wrong actions) If you are doubtful about believing in God, you are better off believing in him, so you are not in a screwed up position once you die. If you believe in Jesus, God promises that your sins are forgiven if you repent. People, I apologize for changing the topic, but it is very necessary for people to hear this “good news” message.

  63. Why do you recommend reverse osmosis water? I have heard drinking RO, DI, or distilled water can cause mineral deficiencies? Is there any truth to this?

    I know we get most of the minerals and vitamins we need from food (or supplements in the modern world), but I haven’t accepted the drinking of RO water yet.

    Funny… I drink filtered tap water but buy distilled water for my potted plants…

  64. Hello, i think that i noticed you visited my website so i came to go back the prefer?.I am attempting to to find things to improve my website!I suppose its adequate to use a few of your ideas!!

  65. Thanks for the article Mark.

    I’ve read differing opinions on how much water we should be drinking, and also when we should drink it.

    In the book Your Body’s Many Cries for Water, Dr Batmanghelidj says a glass of water 30 mins before a meal will aid in digestion, and then to drink another glass 30 mins after the meal ( https://www.watercure.com/ )

    Dr Mercola, someone whos articles I’ve read for the last few years says to just drink enough for your urine to be light yellow in colour and the amount of water needed to achieve this will vary for everyone.

    I’m fairly new to Paleo eating, but what you say here regarding our ancestors does make sense to me. Although when you see dogs and other animals in the wild drinking pure water I guess our hunter gatherer ancestors may not have gotten ALL their water from food alone, just the majority of it.

    I go through phases of drinking more water and then I soon get bored of it. Before I started eating a more paleo type diet i always had dry mouth, I would try drinking water to fix it but that never seemed to work, and drinking more water seemed to just make me more thirsty and it was a viscous cycle. Only when i drank sweetened beverages did my dry mouth disappear.

    I started drinking more water again a couple of weeks ago, what I’ve noticed is I’m more hungry soon after I drink a glass, I saw this is a good thing, stimulating my appetite and helping my digestion, but now I’m not so sure. Also I sometimes suffer from red patches of skin on my face, eating paleo has helped it, I think it might be dairy related, but I have noticed when I suddently start drinking more water the red patches come back the next day and sometimes my skin feels more dry.

    Eating paleo has sometimes left me very hungry and now I wonder if it could be due to the extra water i was drinking. When i got back into increasing my water consumption several months back it made me sleepy initially, but that phase passed after a few weeks.

    I also liked adding a liberal amount of unrefined sea salt to my food and think this have been another bad practice. I have adrenal issues and am hoping paelo will fix that and figured my salt craving was related to that.

    Sorry for the lngthy post, now I’m going to be cutting back on the water I drink for a while to see the effects and redcuing or eliminating the amount of salt I add to my food.

    1. That study is worthless. It states there is no evidence of cause and effect, and there’s not.

      It’s interesting, nonetheless, because there are vasopressin receptors in the liver. We tend to produce more vasopressin during the night and as the night goes on, and this might be one of the body’s ways of keeping blood sugars stable as we “fast” during the night.

      So intersting study, even though I think they’re barking waaaay up the wrong tree.

  66. I am a “thirsty person”, however I don’t drink it all the time; in the morning I guzzle half a liter, then in the afternoon I usually have a couple of glasses, and the evening I might have a glass if I am really thirsty. I drink more if I am fasting, I guess because I am not eating food with water in it? I mostly don’t think at all about it except when I get thirsty. I am trying to cut back, definitely was drinking far too much before. I sort of gauge it on how often I am going to the bathroom. :p

  67. I really don’t think drinking water with meals is a bad idea, and I don’t really get where that idea comes from. Even if it does dilute your stomach acid, your stomach can produce more, plus the water diffuses out of your stomach- it’s not like a water balloon or something.

    When I’m eating, I drink lots of water, and it’s not because I’m forcing myself to. If I tried to eat a meal and didn’t have any water, I’d frickin hate it; I’d be so thirsty!

    I really don’t think this is unusual- this is why restaurants serve water at meals, and keep coming around to refill your glass. If it was BAD for you to drink water while eating, why would we have an instinctual urge to do it? It seems anti-Primal to claim that.

    Also, I want to say that for me, this isn’t due to carbs. Even eating meat and veggies (no grains), I’m still thirsty.

  68. I tend to sweat and drink a lot, and obviously more when I go to the gym and workout. I probably tend to have about 2.5 litres of tap water a day and can even drink anyway up to 4 litres a day (that’s usually when I’m fasting). This post changes the way I think about water, although I think at least for now I will still drink a lot, I’m not sure why but I’ve always seemed to drink large amounts of water everyday, but will try to experiment and see what happens if I drink less.

    1. Oh one other thing. I heard somewhere (probably from livestrong.com) that your body can take up to 6 litres daily, although I’m sure your body would have side effects if you had that much. How much can your body take? Is my 2.5-3.5 litres damaging or just really thirsty?

      1. If you drink over 3 litres per day without an obvious reason, and can’t help it, you might consider getting tested for diabetes insipidus (nothing to do with regular diabetes). It’s unlikely you have it, but that’s about the level of fluid intake that, if unexplained, they’ll generally recommend being tested. It’s easily tested.

  69. My father-in-laws girlfriend had a seizure while driving in January and hit a telephone pole. She’s fine, luckily. The doctor stated she had the seizure, because she drinks too much water which flushed all the electrolytes from her system and made her “whacky” (his word, obviously medical jargon). Drink when your thirsty he said. Thirst is not the beginning of dehydration.

  70. Mark, thanks for the thought-provoking article. There are so many comments here, I’m not sure whether anyone has mentioned vasopressin. If you chronically drink a more fluid than required, you will chronically reduce how much vasopressin you produce; otherwise, you will become hyponatremic, which becomes life-threatening as you have pointed out.

    About a decade ago, I was (incorrectly) diagnosed with diabetes insipidus due to inability to produce sufficient vasopressin. Vasopressin stops you from losing fluid. When you don’t have enough vasopressin, you drink a LOT (5+ litres per day). I can tell you that for me, at least, it was very unpleasant drinking this much fluid.

    One of the things I noticed was that I constantly felt very cold. Now, I’m being speculative here: I wonder whether this has anything to do with the fact that vasopressin increases peripheral vasoconstriction, which reduces heat loss.

    In the spirit of your whole philosophy, it would seem to make a lot of sense that vasopressin does this. Typically, when it is cold, we don’t sweat and we don’t need to drink as much. Provided we don’t drink excessively, we will produce vasopressin and it will help the vasoconstriction needed to regulate body temperature. Perhaps. I can’t seem to find out whether this is accurate. What I do know is that I tend to feel cold when I drink excessive fluid, and have insipid/dilute urine (which definitively indicates a lack of vasopressin).

    Vasopressin has known functions in memory and possible effects on sleep, among other things.

    Chronically drinking excessive fluid means chronically suppressing the release of vasopressin.

    I doubt human beings are supposed to do this.

    In my case, it turned out that I could produce vasopressin once I stopped excessive fluid intake, and I now think I know what caused the excessive fluid intake at the time.

    I saw an endocrinologist whose PhD focused specifically on vasopressin. He told me that if he saw his patients walking around with water bottles, he’d be very concerned about it.

    He also said it’s often very difficult to dinstinguish between polydipsia (excessive thirst/fluid intake) and diabetes insipidus (inability to make or respond to vasopressin).

    So like you, I take on board comments here that some may need to drink more fluid, and of course I understand some of what you say in the article is speculative. Also like you, I find it very difficult to believe that human beings are designed to drink fluid in excess of what they require. I also wonder what unforseen consequences there are, and think that chronic suppression of vasopressin shouldn’t be overlooked.

    1. Snapper,

      vasopressin is new to me. thanks.

      your theory about too much water -> less vasopression -> cold is very interesting

      i’ve been reading Primal Mind Primal Body; she, like some others, says that most are chronically dehydrated on a cellular level. i am pretty skeptical.


  71. My teenagers have always been homeschooled and allowed to eat and drink when they want. What I find interesting is that they drink very little. My son will make hot tea in the morning and have a cup of water later in the day, but otherwise that is all. Same with my daughter. They drink very little. However, they eat fruits and veggies throughout the day. I always like observing them because they haven’t been influenced by as many outside sources and follow more of their natural rhythms.

  72. Mark,

    Have you ever read “Your Body’s Many Cries For Water”. I has a lot of interesting things about water. I’m not saying it would change your POV, but you should read it, nevertheless.

    The most compelling thought I encountered on the subject of water in your blog is the idea that the evolved thirst mechanism would be imperfect. I find that hard to believe. Nevertheless, the author of “Your Body’s Many Cries For Water” performed many clinical studies on water with which I believe you should acquaint yourself.

    Bob Magness
    825 Harbor Oak Lane
    Clearwater, FL 33756

  73. This is why Grok drinks less.
    Fats releases more water in the blood.

    “How to get that push? Some might say drink more water. But ingested water doesn’t reach capillaries, at least not very effectively. What does cause efficient water production at the capillary level? Metabolism, and according to biochemistry texts:

    * consumption of 10 grams of protein releases 4 grams of water
    * consumption of 10 grams of carbohydrates releases 6 grams of water
    * consumption of 10 grams of fat releases 10 grams of water.

    “This release of water comes only when sufficient oxygen is present in the blood., and moderate, regular exercise is the most effective way to release more oxygen into the blood.

    “Sufficient oxygen plus a metabolism in which cells live predominately on fats results in the most efficient pump, the healthiest circulation, and a healthier heart. Thus the strategy with any “dis-ease” of the heart is to slowly increase the percentage of healthy fats in your diet while at the same time increasing the amount of moderate exercise you do.




  74. I drink a lot of tea and sparkling water just because I enjoy it, and I often chug about 8oz of icy cold water in the morning simply because I’m super thirsty, but I found when I was trying to get eight 8oz glasses a day, ignoring coffee as a source of hydration(following that trusy old CW, eh?) I was literally forcing water into my mouth and I was peeing like crazy!

    Now I usually have my coffee, some tea, a glass of sparkling water and maybe some plain water if I’m really thirsty. I feel fine! Following my thirst is probably the best idea, because I think about it and why would my body fail to alert me when it’s time for water? Well, it wouldn’t, I don’t think.

  75. Hi Mark,
    I have been trying to watch what I eat in hopes of losing about 40-50 pounds and while on this journey I have been drinking around 64oz of water a day, Well i had a stent put in on Oct 25th and almost died. Ever since trying to lose weight, I drink nothing but water and I can’t lose weight because the scale keeps going up and down which I assume is water weight. Well I went to my Heart Dr today for my 4mo check-up and wanted to be put on a water pill to help with this water issue, my Dr told me to stop drinking so much water and all these yrs we have been told the opposite. So will drinking less water increase my weight loss for good ? I don’t limit anything in the way of food and eat everything in moderation because I don’t feel anyone should go without what they want. I am NOT diabetic and I do exercise, I just need advice and see why I can’t seem to lose instead of juggling numbers on the scale Can you help please ? Thanks

  76. Nice post Mark! I was wondering about the primal take on water since fresh water sources would probably be more prone to parasites and other disease than getting your intake from food. The dilution of stomach acids is also an interesting take!

    Anyway, my question is about water intake as applied to ketosis. In keto they recommend additional water and electrolytes for the process tends to dehydrate people. Should I continue to supplement water for keto, or should I quit worrying about it as much?

  77. “– if a source of water other than a dewy leaf was even available.”

    Grok didn’t live like Survivorman in the middle of nowhere. Almost all of their societies lived directly on or close to a major water source; and if they didn’t, they were experts at extracting water.

  78. I know this is a really old post, but I have a question. I’m the opposite when it comes to drinking water – I ALWAYS want to drink something. I’ve been that way my entire life – my preschool teachers thought I had diabetes because I drank so much, but I don’t. I also can’t think that my water requirements are -that- high, being a 105 pound female. I do run outside a few times a week and am in general very active, but I barely sweat. I just go to the bathroom A LOT. Could there be any reason for my incessant thirst?

  79. ever since i’ve read the book “your bodies many cries for water” by dr. batmanghelidj i’ve been drinking a lot more water, especially in the morning before breakfast – usually around 16 oz. and 12 oz. of tea. i do get really cold drinking lots of water. the funny thing is i don’t pee much. is that normal?

  80. This has really opened my eyes. To think that all these years, all these digestive issues and migraines and all the cr*p caused by my gluten intolerance could have been avoided by me not chugging water and juice? Wow.

  81. The book Fiber Menace has taught me that the 8 glasses of water a day is to include all sources. That is from what you drink to what you eat and from oxidation. You eat approximately 3 cups of water a day. Even more if you eat a lot of and vegetables. You produce 2 cups a day through oxidation and that leaves approximately 3 cups to drink.
    You drink too much water and it depletes your body of vital minerals. Especially potassium and sodium chloride. You need potassium to lube your poo. You need salt for your body to be able to make hydro chloric acid for your stomach.
    You should never drink during or after a meal. It just dilutes your stomach acid and so your body needs to produce more to get to proper levels. This can cause heart burn and delays digestion.
    He also said you shouldn’t have to urinated anymore then 3 to 5 times a day and never at night. You are drinking to much if that is the case and if your urine is clear and in large volumes.
    I highly recommend his book Fiber Menace it has taught me a lot. You can read the first chapter for free at http://www.gutsense.org

  82. Water- looking to do the wright thing for my water intake.

  83. I am really feeling like a fool right now about forcing my 3 year old daughter to drink water when she really doesn’t want to (and eats a pretty primal diet compared to most kids). When she’s thirsty she asks for it. And a bigger fool about drinking water when I haven’t really felt like but just did because “we are supposed to drink 8 or so glasses of water a day”. I am beginning to realize that trusting your body’s signals are more intelligent than blanked advise we have been dished out.

  84. I think I drink too much water and my mom is worried about me displacing my sodium because I am a runner. I don’t know how to prevent myself from drinking so much because I always feel thirsty. I keep asking for help from my parents, but they don’t seem to know what to do either because they always avoid my questions. I also am always hungry and I don’t know how to stop eating, because I am slowly but surely gaining weight, like a couple of pounds a month. I try to run harder or more, but this makes me hungrier and thirstier and then just exhausts me, so I am like running around in a circle. I don’t know what to do. You seem like a smart guy so maybe you can help.

  85. Having grown up in Africa I’d observe that any early man drinking even small quantities of unfiltered or unboiled water would be unlikely to live very long. Waterborne diseases would have done for him long before marauding carnivores.
    Assuming that he wasn’t stupid, (and if he was would we as a species have survived this long?) he would have had at least an inkling of the danger. Even today you will not find herders and people who live in the bush drinking water they find in streams and rivers.
    Early man would not have had very efficient means to carry water with him in expeditions so I would think it’s a fair bet that he got almost all his water from the food he ate and that he took the chance to eat fruit whenever he could. Fruit being the perfect filter and container for water in the wild.
    If they were cooking food then most of their water would have been contained in stew like dishes which are still a staple of African indigenous cooking. Those habits probably travelled with him as he spread out around the world and not until he discovered high altitude meltwater streams in the north would he have dared to drink much fresh water.
    With that in mind I imagine from a physiological point of view we are adapted to extract the water we need for normal to moderately strenuous activity directly from our food. Early man would probably have avoided super intense activity that made him sweat a lot or he would cover himself in mud or oil to prevent excessive sweating and loss of water that he couldn’t easily replenish.

  86. ROW takes the good things out of water.
    They say to drink water when you have a salt craving because you are probably missing some minerals.
    But you say drink ROW….

  87. I actually gave up on keto because i felt anxious and tired all the time, now I realise its because i was flushing all my electrolytes out constantly, too much water!

  88. Lance Armstrong, the ultimate lab rat post cancer, religiously drank 2 gallons of distilled water a day. Wonder why?