Doctor's Note

This is the third of a video series on water. See the first two at How Many Glasses of Water Should We Drink a Day? and Does a Drink Of Water Make Children Smarter? Stay tuned—I’ve got more on the way.

Other healthy beverages include hibiscus tea (Hibiscus Tea vs. Plant-Based Diets for Hypertension) and green tea (Dietary Brain Wave Alteration).

What else can affect our mood?

What about the omega-3s in fish? That’s the subject of my next video: Fish Consumption and Suicide.

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  • Noe Marcial

    Let’s try the test here in Spain with 35 c… All of Spain is half dehydrated… Haha . What about the color of the pee? It is any chart? What it means if is quite yellow ? A now it is a relation with dehydration but are other factors that make that colour? I notice when I was close to a flue or some tthrout pain or omething like that the color gets much yellow … Even drinking equal amount of whater…

    • merrly

      I’m curious about this as well as color doesn’t seem to be a consistent factor of how much water is consumed or if one is dehydrated from what I’ve looked up.

      • Jeewanu

        The yellow color is from metabolism of haem groups. I’m just guessing but If you eat a lot of meat you could see an increase in color intensity compared to strictly plant foods I try to eat beetroot every day and my micturations are a beautiful orange color. La!

        • Robin

          I find when I take vitamin B my pee is bright yellow
          When dehydrated my pee is dark yellow
          Some times when I ride my bike 10 miles home from work up and down hills I get dehydrated dripping with sweat get home pee and drink to top off then shower and drink more. Its a really great ride on my one speed cruiser

      • largelytrue

        It should be obvious that the intensity of urine color depends both on amount of urine and the amount of coloring agent present within it. Water dilutes the colored solutes that are excreted, while other factors influence the amount of solutes that are excreted. On top of this, people don’t usually do a full accounting of their water balance, but mostly just judge in terms of what they have recently drunk and how much they seem to urinate.

        When you have a microbial illness there are a number of things that can happen which tend to dehydrate you. You can run a fever, increasing metabolic demands and the moisture lost from breathing and sweat. You can turn away from food which contains water, and vomit up part of your recent meal, which also contains water. You may experience diarrhea, which also adds to water loss.

        The yellow pigmentation of urine is most normally due to urobilin, which, like the bilirubin that makes feces brown, is a product of the body’s effort to discard heme. A lot of this comes from the cycling of old red blood cells, but people also vary in their consumption of heme iron.

        People on low-carb diets often seem to discuss weird-colored urine as a fairly commonplace thing (e.g., and sometimes attribute the yellow pigmentation to urea, which is a waste product that will tend to increase with massive protein consumption. This is an unlikely explanation, however, since urea is clear as a solid and in solution with water, and apparently quite resistant to color change reactions in general.

        Instead, it seems that an increase in yellow pigmentation on a low-carb diet would more often be due to the massive consumption of red meat: muscle tissue which contains myoglobin which contains heme. Massive supplementation of B-vitamin complex could be another cause of increased yellow pigmentation (evidently riboflavin has a very yellowish color), and since urine is basically a dumping ground for the body’s water-soluble wastes, there are many other possible contributers to urine color:

  • Daniel Wagle

    Could eating a lot of carbohydrates cause water storage, since it takes water to store glycogen?

    • Philip

      The information I’ve seen on this is that you can loose about 6 to 8 pounds in water weight if you fast or diet. Since “a pint’s a pound, the world, round,” for the weight of water, that’s six to eight pints of water bound up in the form of glycogen.

      • Brux

        “a pint’s a pound, the world, round,”

        Ha, never heard that before, thanks.

      • Carolyn

        In the UK a pint is 20 fluid ounces, and a pound is 16 oz, but I don’t think “a pint’s a pound and a quarter” really sounds as good!

        • Brux

          That’s interesting since this is called the English system?
          In the US we learn that a pint is two cups; a quart is four cups or two pints.
          What is a cup in the English system? … 10 ounces as opposed to 8 ounces?
          In your English system what is the relationship between a pint and a cup?

          • anon

            When we cook in the UK we tend to use scales rather than cups – I find using cups really irritating and if I find a US recipe the first thing I do is convert it to weights rather than volume (how the heck do you measure a cup of carrots for instance?)! I do have a set of cups though and a cup is 250ml so the conversion isn’t exact. 8 pints is a gallon here, but obviously total volume of the gallon will be bigger than your gallon. (This is from Carolyn again – I’m not sure whether I’ve remembered my password!)

    • steve41337

      I don’t know the answer to your questions but I will offer the following personal observation. After my first three years on a 100% plant-based diet (with no added oil) I notice I cannot drink as much water. I used to drink on average two or more quarts a day (assuming I was not outside working) and since eliminating meat, fish, cheese, and milk I have a hard time downing more than 1 to 1.5 quarts a day. Someone told me that it takes a lot of water to digest protein compared to carbs. Is there anyone who can confirm if that is true?

      • largelytrue

        A pretty direct effect of protein catabolism is the production of urea, which is expelled by the body. More urea to expel would probably tend to promote greater urine volume, there being less work required of the kidneys to eliminate the urea when the urine volume is allowed to be larger. This would prompt more water drinking, but another important effect is that most animal foods are comparatively dry to begin with, which could account for part of the difference that you are apparently noticing.

        It doesn’t seem that the metabolic water from oxidizing a calorie of macronutrient depends too much on the type of macronutrient in humans, at 41, 55, and 107 grams water per 100 grams protein, carbohydrate, and fat, respectively ( ), though carbohydrate liberates a little more per calorie than either fat or protein. This makes intuitive sense, since carbohydrate is generally the most efficiently stored form in biology in terms of retaining the energy used to build it, while fat is the most efficient source of stored energy per unit mass or volume, and protein is generally a secondary energy source, being more important as a structural component and an enzymatic tool that closely follows the instructions of the genetic code.

        1 part glycogen is stored together with 3-4 parts water in the body, but it’s important to understand the exact sense in which this water can be said to be stored. It isn’t simply available to go into the plasma whenever it is needed, but rather it is locked up in the matrix which stores the glycogen. As your body takes the glycogen out of storage and uses it, the water will be liberated.

  • Plantstrongdoc M.D.

    Diuretics are often prescribed (hypertension, oedema, heart failure) to the elderly population – one well known side effect is dehydration. The elderly frequently dont drink enough water for various reasons – they dont feel thirst as well as a younger person, deliberately so they don’t have to go to the restroom so often, to avoid getting up at night and so on. Conspicuously many of the older population are prescribed antidepressants. There may well be a connection.

  • Rodger

    When you think about it, how silly is the need for written guidelines to tell us how much water to drink when we have an instinct called thirst which informs us better, more accurately, and quite naturally? On the other hand, forced drinking resulting in too much water can cause low sodium concentration (hyponatremia) along with encephalopathy. So, it seems that too much water is just as bad as too little. The bottom line is: follow your thirst, not some cheesy bogus advise. See:

    • Brux

      I’ve heard that thirst sensation sometimes works and sometimes not. That older people either lose their sense of thirst or do not follow it. There must be some reason people get dehydrated otherwise we would not be talking about it.

      These days it could be that our sense of hunger and thirst are thrown off by other things. 100 years ago how often did anyone drink soft drinks, or flavored drinks? I think most people drink water.

      • Charzie

        I was thinking the same thing. The more unnatural our lives get, the more we lose our natural abilities!!! I know so many people who NEVER take a drink of water at all! It boggles me because I am a H2O chugger!

      • Leo

        Thirst and hunger center are close together in the pituitary, almost winding around each other like a ball of spaghetti. Many feel thirst, but interprets it as hunger and go to the fridge to eat something.

      • Allan

        Thirst is also mistaken for hunger in many cases. Water (alkaline) is my field of study and I’ve learned many things about this wonderful substance we use everyday. Did you know if you are growing your veggies with water that has had the chemicals removed they will taste different and better? Water which is cleaned of contaminants is much better for you to drink.

    • Psych MD

      I have seen a number of schizophrenics over the years with psychogenic polydipsia, an irrational urge to drink water. Several diluted their electrolytes to the point they began seizing.

      • ReluctantVegan

        I have a friend who has been on lithium for 16yrs and is trying to wean himself off by reducing his Li by 6% a month. Before he started reducing, he came to our house for dinner and drank about 7 dinner glasses of water throughout the evening. It was excessive. He said the lithium made him dehydrated, but I think it was a psychological tick “psychogenic polydipsia”. He kept peeing all night – so I guess he wasn’t dehydrated. Maybe he should get checked for diabetes, but he is very trim – doesn’t fit the picture.

        • Psych MD

          I don’t prescribe lithium much these days. Long-term lithium use is fairly frequently associated with thyroid and kidney complications and periodic blood testing is mandatory. As for your friend, I would hope that the lithium is being prescribed by a psychiatrist and that he/she is managing the change. Furthermore, the principle indication for lithium is bipolar disorder. Assuming that is the case here, another mood stabilizer would need to be started in its place to avoid a relapse.

          • ReluctantVegan

            Thanks for that good info. He does have bipolar disorder – I don’t know if he is being managed by a psychiatrist at this point – I doubt it as he hasn’t mentioned starting an alternate med. I’ll pass on what you said. Thank you.

    • steve41337

      There have been studies that show thirst cannot be trusted to know when you’re dehydrated. If thirst can be trusted as a sign perhaps the problem is paying attention and doing something about your thirst? Think about the video we all just watched here and the chart that showed so many folks were dehydrated. Dah! My favorite study was one mentioned by Dr. B. in one of his books I read years ago involved a large group of people who were observed through a two way mirror during a day long seminar. The entire day during the seminar water was withheld and not available to the attendees. During the last 1/2 hour or so they put water pitchers and glasses on each table and the seminar participants were watched by study observers behind the mirror. One of the findings was that the older you are the less you can trust thirst to keep you hydrated. Some people never drink water. And I have met people who proudly tell me they don’t drink water because they don’t like it.

  • Brux

    1:58 >> “Cold water gets sucked into the body about 20% faster”

    You learn something every day I guess … I never would have thought that.

    • Wade Patton

      probably something to do with density. I had heard this many many moons ago, never doubted it.

  • Charzie

    Getting older definitely plays a role, but I think taking certain, and especially multiple pharmaceuticals is a huge issue that compounds it! (Sadly I learned from PAST experience!) Other age groups are so warped by the chemically created taste-pandering industries they seem to have forgotten water completely! Sad and scary!

    • Plantstrongdoc M.D.

      Electrolyte disturbances eg. low sodium also has a negative effect on brain function – Again the elderly are at the highest risk. Various frequently prescribed drugs can lead to low sodium – eg. diuretics, antidepressants and NSAIDs (over the counter painkillers). Especially if you combine the drugs – and we all know an elderly with hypertension, depression and arthritis (all preventable and possible treatable with a plant based diet – but instead we take drugs that create a fourth problem)

  • Panchito

    Three components, ceramides, cholesterol, and saturated fat make up the skin barrier that prevents moisture loss. If you suffer from dry skin, usually associated with dehydration, take a look at the following quote from Wikipedia:

    “Ceramide is the main component of the stratum corneum of the epidermis layer of human skin.[10][11]
    Together with cholesterol and saturated fatty acids, ceramide creates a
    water-impermeable, protective organ to prevent excessive water loss due
    to evaporation as well as a barrier against the entry of
    microorganisms.[11] With aging there is a decline in ceramide and cholesterol in the stratum corneum of humans.[12]”

    Wheat oil is supposedly rich in phytoceramides.

  • jj

    There are people who think they are hungry when they are actually thirsty.

    • ReluctantVegan

      I have experienced this. I think I am hungry, take a bite of something and realize that I am not interested in eating or that I am already full. At some point (before I ate WFPB diet) I realized I should consider the possibility that I may be thirsty rather than hungry. So now, if it is not mealtime and I feel hungry, I try water first, and then if that doesn’t work, I try food. Sometimes I still forget and try a snack that doesn’t satisfy, and then remember water.

  • Leo

    I did some calculations. If you drink 0.5 liter of water at 12 ° C = 4 degrees F, and your body warms it up to body temperature, 12 kCal is needed.

    To do this you need to use 1.3 g fat or 4 g carbohydrate, or 4 g of protein. A kind of weight loss …

    Or more dramatically, the heating corresponds to the same energy as to lift 500 kg 10 meters above the ground, which corresponds to the ceiling of the third floor

    • thorn324

      Leo, I think you’ve a few errors in your calculations. (1) 12° C = 53.6° F. (4° F is 28° F below freezing: so though the water may be potable it most certainly wouldn’t be pourable—or drinkable at 4° F!) (2) 4g of carbohydrate or protein = 16 kCal since each of those macronutrients is 4, not 3, kCal per gram.

  • Leo

    I remember a funny thing. The body has a lymphatic system that removes waste substances. The brain has no room for lymphatic vessels. Therefore, the brain shrinks in the night to be flushed clean by the lymph fluid. In the morning, the brain has expanded again.

    A good night’s sleep is important for maintaining a detoxified brain.

  • David Hochstettler

    I like water but I don’t drink anything. I eat about 7 pounds of food a day (plant based diet) which is about 95 per cent water. If I drink very much water I am up all night visiting the restroom. Is it bad that I don’t drink?

    • Psych MD

      That is interesting. I never considered the total mass of food I eat. I eat a lot of nuts, seeds, and grain, all of which are relatively dry. I do drink about 8 lbs. of tea (and 0.5 lbs. of red wine) per day.

    • Wade Patton

      NO. If your urine frequency and color are good, then you’re good. Right after I went smoothie/raw foodie some years ago I went on a 60-mile bike ride. I tried to drink like I used to drink (water on long rides). I wound up having to stop every 10 miles!!! I was more hydrated than ever and my elevated usage did NOT require the “usual” level of water consumption. Folks need to drink and urinate regularly-will vary according to many factors. Eating whole, especially raw, foods will greatly decrease the amount of “extra” water necessary.

  • Psych MD

    It’s an amusing coincidence that an hour ago I was standing in line at a checkout stand and saw a display for “Liquid Genius,” “inspired by the clouds.” I scoffed at the time but apparently, according to this video, they may be on to something. They can legitimately claim that their product can make your brain larger.

  • Youcef

    I generally find your videos worthwhile and very interesting.
    But the effect of dehydration on mood? I thought it was April 1st but it isn’t.
    I wonder what era we live in when people of high science, collect articles that cost thousands of dollars of funding to find out that dehydration affects our mood?!
    Have you even been thirsty in your life? Ever? Or even remotely been in touch with how your body feels?
    What next?
    Does being hungry affect our mood?
    Does being sexually aroused affect our mood?
    Does feeling too cold affect our mood?
    Does feeling too hot affect our mood?
    Does having fever affect our mood?

    Please, for the sake of the content value of this website don’t dwell into the high science of trivialities.

    I’d like to see a video about how to help people that can’t drink, people that don’t like water and are in a chronic state of dehydration. I call them hydrophobic and I know a few. Perhaps there are methods, techniques, etc…I think that would really help rather suggesting people (who are the most likely to be hydrophobic ones) to what drink 750 mL of water to see how much they pee in an hour. That’s is IMPOSSIBLE for many hydrophobics to consider such amounts without some sort of tweak.

    • Plantstrongdoc M.D.

      I disagree. This is very relevant. You don’t feel chronic dehydration – there is no thirst. Hunger, cold, fever and so on are linked to emotions. The cause of fatigue, lower levels of vigor, confusion and bad mood, can be something that you are not aware of – chronic dehydration (not thirst). Most people probably know if they are sexually aroused…..

      • Youcef

        @Plantstrongdoc M.D.
        The question is “Does dehydration affect our mood?”
        You said : “The cause of fatigue, lower levels of vigor, confusion and bad mood, can be something that you are not aware of – chronic dehydration”

        My answer:
        Right. Well, here are a few exercises to avoid finding oneself in a situation of such ignorance about the source of the problem:
        1) Put a plant in your office/room. Describe your primary responsibility with the plant.
        1a) Fail that responsability chronically, and observe if it has or not affected the mood of the plant.
        2) Open a book about the history of our planet, and write down all the references about the importance of water as the base for life.
        3) Search for the percentage of water :
        a) by weight (human body)
        b) by molecular percentage (human body)
        c) by percentage of graphical representations in medical textbooks that display water in the environment (of a molecule, a cell, of DNA…)

        In other videos, I was occasionally very critical but on rather biological
        trivialities. This video really marks a whole new level of
        disconnection with the most fundamental biology but also reality of life. Very concerned!

    • steve41337

      I strongly disagree with you. Dr. F. Badmanghelidj spend his entire life studying the effects of water on the body and claims to have cured thousands of people of depression by simply having them drink more water. He once made an offer through a TV station in PA (via an auto parts company owner who advertised in the local area) offering $25,000.00 to anyone in the area with a child with asthma they could not cure in two weeks by simply having them drink less sugary soft drinks and more plain ole water. They claim they never had to pay out a penny.

      • largelytrue

        I suspect that you’ve gone pretty deep down the rabbit-hole of anecdote and are probably lumping too much hope into one cure-all mechanism, where you should instead have some skepticism about the intellectual character of the person making the claims. Seriously, the late Dr. Batman denied that HIV causes AIDS:

        Note that he wasn’t willing to submit to the rigors of peer review before posturing as if his ideas on this matter had the authority of institutional science, either. The Journal of Science in Medicine, Simplified, was published by the Foundation for the Simple in Medicine. This publishing corporation was founded and controlled by — you guessed it — Dr. Batman himself:

        There is a wide range of people who seem to advocate that urine should always be clear, and we can see some attractiveness in the idea for the apparently ‘pure’ connotations and the apparent ease by which the criterion can be checked. That said though, the classic 8-point scale is not exceptionally well-validated for accuracy with self-assessment and the relationship with overhydration at the low end of the scale is not well explored: By definition, clear urine opens up the possibility of overhydration, and trying to have clear urine at all times will accentuate this effect.

    • largelytrue

      Obviously being thirsty affects mood in a general sort of way. We perceive a need that tends to intrude on our mind, become more intense with time, and makes us feel unhappy on some level that the need is not fulfilled. Even so, the effect on our mood of these kinds of signals from our body varies quite a lot from one situation to another. Sexual arousal is a strong example of this, I think. Even more important is the point that thirst doesn’t exactly equate with dehydration in some groups of people, which is part of what has been motivating this research.

      So no, it’s not necessarily trivial to ask if dehydration (as opposed to thirst) has a significant and persistent effect on mood, and what sort of effect this is if so. You yourself seem to be interested in the people who insist that they are not thirsty (why is it that you don’t take their word for it in these cases?) but who aren’t euhydrated in your opinion. The extent to which we can be dehydrated without feeling thirsty is worrisome, because it presents situations where we can’t rely on how we feel to regulate our bodily hydration, even in principle. However, the study on which Greger’s water challenge is derived ( ) suggests that, for “healthy men” at least, thirst itself is an active sign of ‘dehydration’ in the sense that worsens mood and impairs performance on certain cognitive tasks (-2% body weight). The researchers in fact remark that the onset of thirst somewhat precedes the mental impairment, as healthy people start to perceive thirst at 1-2% loss. A secondary measure through a “challenge” is valuable, but not as valuable in this kind of group as it might be for others who might be expected to have greater problems with sensing thirst or with planning their behavior so that feelings of elevated thirst do not arise.

      The more impressive idea on euhydration in the healthy is from Greger’s other video, where a cardiovascular benefit to drinking water on top of the diet was noted in Adventists, who eat a comparatively healthy diet overall:

      Even this result is a bit less impressive, though, for those who think that they have taken measures which already place them at low risk for ischemic events, and absent a more refined understanding of what exactly led to the benefit and how. Pushing blood viscosity down a bit is probably good, but the increased loss of minerals and salts may outweigh the cardiovascular benefit in some people, especially on a water-cooked plant-based diet such as many people here adopt. Drinking several cups of fluids throughout the day should probably be regarded as normal for most people, but that isn’t the whole story, either.

  • KHanPark

    Drink water. Not sugar water

  • windabella55
  • Bat Marty

    Raw foodist think that humans need to learn to drink because for us is not natural to drink water but instead we were designed to eat mostly fruit and that’s where we’d get our water. That could explain why we don’t feel the natural urge to drink most of the times. When I eat raw ;mostly fruits and veggies( I never drink water but I go to the bathroom a lot thus I am never dehydrated. (Also a beginning of arthritis went away since I added much raw food in my diet last year)

    • Wade Patton

      Yes, one of the primary things most cooking methods do is remove water from the food. Anything processed generally has had the water removed. THIS is why most people need to consume so much “extra” water. It is to replace all the water that was originally IN THE FOODS they are consuming modified forms of. If a raw foodie tries to drink the “required” amount of water, he/she will go crazy urinating all day. Tune in to your body and common sense rather than “hard and fast rules” as to such basic things. Life was simpler when chilled water was freely distributed around this country. Here in the South iced water was automatically delivered to every person who sat down in a restaurant, GRATIS.

  • windabella55
  • Rodrigo Cardoso

    Portuguese translation will begin in this link. Feel free to help complete it:

  • Rodrigo Cardoso

    Now also available in Portuguese:

  • Antinutrient

    I am currently fighting a – possible virus induced – chronic headache and I have learned that I need to drink significantly more than I used to do in order to keep the symptoms down. I currently average around 3 liters of water a day, depending on weather conditions (Scandinavian climate), on top of the water I get from food. I have noticed that even the slightest dehydration makes my headache a lot worse and this happens a long time before I feel any thirst at all – also it seems that fluids from food, beverages and juices does not do the job, it needs to be clean water.

    So again, how much water you need depends very much on your situation and condition.