Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
9 Jun

Drink Less Water?

Drink WaterDear 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?

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You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. 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.

    Suttikorn J. wrote on May 25th, 2011
  2. I have always felt this way. I drink when I am thirsty. Thanks for your point of view Mark.

    Leah VanHoose wrote on August 2nd, 2011
  3. 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.


    James wrote on August 2nd, 2011
  4. 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.

    astral travel projection wrote on August 20th, 2011
  5. 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.

    miss J wrote on September 16th, 2011
  6. 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…

    Gladmore wrote on October 24th, 2011
  7. I thought drinking water helps prevent constipation

    Steve wrote on December 2nd, 2011
  8. 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!!

    weight loss drink wrote on December 10th, 2011
  9. 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 ( )

    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.

    Scott wrote on December 31st, 2011
  10. Take a look at this study…(drinking less water leads to high blood sugar)

    Not sure who to believe, lol.

    Anyways, I’ve started drinking 3 to 4 litres a day (while dieting – low carbs, slow carbs, I’m not sure). I’m down about 7 lbs in 3 weeks. (got about 15 – 20 to go).

    Joe wrote on January 11th, 2012
    • 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.

      Snapper wrote on May 21st, 2012
  11. 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

    Mary wrote on January 25th, 2012
  12. 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.

    Ali wrote on February 21st, 2012
  13. 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.

    Molly K wrote on May 18th, 2012
    • Oh one other thing. I heard somewhere (probably from 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?

      Molly K wrote on May 18th, 2012
      • 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.

        Snapper wrote on May 21st, 2012
  14. 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.

    Turling wrote on May 18th, 2012
  15. 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.

    Snapper wrote on May 21st, 2012
    • 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.


      pam wrote on May 22nd, 2012
  16. 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.

    Cathy wrote on June 28th, 2012
  17. 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

    Bob Magness wrote on September 28th, 2012
  18. 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.

    Michael wrote on January 31st, 2013
  19. 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.

    Rebecca wrote on February 2nd, 2013
  20. 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

    Tizz wrote on February 28th, 2013

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