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Is Water Weight a Myth?

klmcneil1klmcneil1 Posts: 26Member Member Posts: 26Member Member
I always wondered why, if you were fasting or doing very low carb or something, people would say that your initial, fast weight loss would be "mostly water weight." That just didn't make any sense to me, why if you're still consuming plenty of fluids but not calories, your body wouldn't be using your fat stores.

So I looked into it a bit and found a lot of explanations that go something like this:
"For example, going on a low carb diet, or cutting your carbs way back, triggers the loss of glycogen and the water stored with it, and if extreme, can also be dehydrating."

Looking into glycogen metabolism, that seems to make sense, since every gram of glycogen is bound to around 3 grams of water. But then I read up on fatty acid metabolism, and learned that it (not glycogen) is your primary energy source between meals. The glycogen stores are only used where fatty acids (triglycerides stored in your fat cells) can't be: in the brain and red blood cells. More importantly, there's only about 100 grams of glycogen stored in the liver: even with its associated water, that's less than a pound. (There's more stored in the muscles, but that glycogen can only be used for energy in the muscles, not transported to other parts of the body like the glycogen in the liver.) So the idea that someone can lose 10 lbs of "water weight" seems unlikely.

I don't know, I'm no biochemist, but this is seeming to me like one of those nutrition "truisms" that doesn't hold up when you actually look for evidence.

What do you guys think?
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Replies

  • usmcmpusmcmp Posts: 21,339Member, Premium Member Posts: 21,339Member, Premium Member
    There's also water stored within cells that is regulated by the balance of sodium and potassium. Many people tend to cut back significantly on sodium when they first start dieting. Most rapid weight loss programs count on that.
  • klmcneil1klmcneil1 Posts: 26Member Member Posts: 26Member Member
    usmcmp wrote: »
    There's also water stored within cells that is regulated by the balance of sodium and potassium. Many people tend to cut back significantly on sodium when they first start dieting. Most rapid weight loss programs count on that.

    True, but it seems like the "water weight" caused by excess sodium is the temporary, "I feel bloated" kind of weight, not a steady state that people are living in all the time (when they're not dieting). Most of the water around your cells is supposed to be there, and will always be there if you're not dehydrated.
  • usmcmpusmcmp Posts: 21,339Member, Premium Member Posts: 21,339Member, Premium Member
    If someone has had a higher sodium diet for a while cutting back on it would cause a significant drop. I eat higher sodium on weekends while still hitting my calories and when I drop sodium again I can lose 4 pounds of scale weight. It's why people freak out that they had a cheat meal and are up 3 pounds.

    Combine that with glycogen and two pounds of actual fat loss put you at 7-8 pounds of weight loss for a week. Potentially more if someone is exercising and depleting the glycogen stored in muscles.
  • 3dogsrunning3dogsrunning Posts: 27,238Member Member Posts: 27,238Member Member
    No. It is not.

    Manipulating body weight through glycogen stores (and dropping sodium as mentioned above) is frequently used by sports where someone has to make weight.

    Before competing in bodybuilding I depleted glycogen stores and dropped water weight.
    Even through my training I could see differences in weight when changing my carb intake.

    As a runner, I see the opposite effect - carb loading before a long run shows up on the scale in the other directions.

    10 lbs may not all be due to glycogen but big changes in diet and carb levels can affect water weight drastically.
  • stevencloserstevencloser Posts: 8,917Member Member Posts: 8,917Member Member
    klmcneil1 wrote: »
    I always wondered why, if you were fasting or doing very low carb or something, people would say that your initial, fast weight loss would be "mostly water weight." That just didn't make any sense to me, why if you're still consuming plenty of fluids but not calories, your body wouldn't be using your fat stores.

    So I looked into it a bit and found a lot of explanations that go something like this:
    "For example, going on a low carb diet, or cutting your carbs way back, triggers the loss of glycogen and the water stored with it, and if extreme, can also be dehydrating."

    Looking into glycogen metabolism, that seems to make sense, since every gram of glycogen is bound to around 3 grams of water. But then I read up on fatty acid metabolism, and learned that it (not glycogen) is your primary energy source between meals. The glycogen stores are only used where fatty acids (triglycerides stored in your fat cells) can't be: in the brain and red blood cells. More importantly, there's only about 100 grams of glycogen stored in the liver: even with its associated water, that's less than a pound. (There's more stored in the muscles, but that glycogen can only be used for energy in the muscles, not transported to other parts of the body like the glycogen in the liver.) So the idea that someone can lose 10 lbs of "water weight" seems unlikely.

    I don't know, I'm no biochemist, but this is seeming to me like one of those nutrition "truisms" that doesn't hold up when you actually look for evidence.

    What do you guys think?

    If you're on a low carb diet, your body uses those stores before going the path of gluconeogenesis and ketosis. Liver glycogen for brain function mostly and muscle glycogen for muscle function. You lose water weight.
  • VeryKatieVeryKatie Posts: 5,441Member Member Posts: 5,441Member Member
    klmcneil1 wrote: »
    I always wondered why, if you were fasting or doing very low carb or something, people would say that your initial, fast weight loss would be "mostly water weight." That just didn't make any sense to me, why if you're still consuming plenty of fluids but not calories, your body wouldn't be using your fat stores.

    So I looked into it a bit and found a lot of explanations that go something like this:
    "For example, going on a low carb diet, or cutting your carbs way back, triggers the loss of glycogen and the water stored with it, and if extreme, can also be dehydrating."

    Looking into glycogen metabolism, that seems to make sense, since every gram of glycogen is bound to around 3 grams of water. But then I read up on fatty acid metabolism, and learned that it (not glycogen) is your primary energy source between meals. The glycogen stores are only used where fatty acids (triglycerides stored in your fat cells) can't be: in the brain and red blood cells. More importantly, there's only about 100 grams of glycogen stored in the liver: even with its associated water, that's less than a pound. (There's more stored in the muscles, but that glycogen can only be used for energy in the muscles, not transported to other parts of the body like the glycogen in the liver.) So the idea that someone can lose 10 lbs of "water weight" seems unlikely.

    I don't know, I'm no biochemist, but this is seeming to me like one of those nutrition "truisms" that doesn't hold up when you actually look for evidence.

    What do you guys think?

    Typically people start exercising when they go on a diet. Hence using glycogen in their muscles.
  • klmcneil1klmcneil1 Posts: 26Member Member Posts: 26Member Member
    If you're on a low carb diet, your body uses those stores before going the path of gluconeogenesis and ketosis. Liver glycogen for brain function mostly and muscle glycogen for muscle function. You lose water weight.

    Do you have a source that explains that? (Medical or academic)
  • stevencloserstevencloser Posts: 8,917Member Member Posts: 8,917Member Member
    klmcneil1 wrote: »
    If you're on a low carb diet, your body uses those stores before going the path of gluconeogenesis and ketosis. Liver glycogen for brain function mostly and muscle glycogen for muscle function. You lose water weight.

    Do you have a source that explains that? (Medical or academic)

    "Glucose is stored in limited quantities as glycogen in muscle and liver, and glycogen is converted back into glucose and released into the blood stream as needed. However, as the body does not have vast glycogen stores, a continual dietary source of carbohydrates must replenish these stores. The body will consume its glycogen stores in a matter of 1–2 days. Low-carbohydrate diets, particularly in the initial introductory phase, contain little or no carbohydrate—restricting intake to below 20 g/day. For comparison, the recommended daily allowance (RDA) for carbohydrate is 130 g/day based on the average minimum amount
    utilized by the brain (FNB & IOM, 2002).
    In the absence of dietary carbohydrate and upon depletion of glycogen stores, the body will begin to metabolize body fat into ketone bodies, which can then be used, albeit less efficiently, by the brain and body as fuel. "

    http://ase.tufts.edu/psychology/SPACELAB/pubs/Atkins_Appetite_inpress.pdf

    You use it up but don't consume enough to replenish them.
    edited April 2016
  • ForecasterJasonForecasterJason Posts: 2,582Member Member Posts: 2,582Member Member
    In practicality, I'm curious as to the thresholds for losing or gaining water weight from glycogen or sodium. As an example, is a 500-700mg drop or increase in sodium enough to cause a couple pound difference from that? Is a 20% reduction or increase in carbs (assuming exercise levels stay constant) enough to cause a 2 lb difference?
  • usmcmpusmcmp Posts: 21,339Member, Premium Member Posts: 21,339Member, Premium Member
    klmcneil1 wrote: »
    usmcmp wrote: »
    There's also water stored within cells that is regulated by the balance of sodium and potassium. Many people tend to cut back significantly on sodium when they first start dieting. Most rapid weight loss programs count on that.

    True, but it seems like the "water weight" caused by excess sodium is the temporary, "I feel bloated" kind of weight, not a steady state that people are living in all the time (when they're not dieting). Most of the water around your cells is supposed to be there, and will always be there if you're not dehydrated.

    I think you would potentially find a lesson on the sodium potassium pump interesting. It would probably help you understand why I mentioned a drop in sodium being significant.
    edited April 2016
  • rileysownerrileysowner Posts: 7,847Member Member Posts: 7,847Member Member
    I cannot comment on much of this, but when my journey started after having a stroke, for my high blood pressure one of the medications I was put on was a diuretic. In a week I lost almost 20 pounds, I was not exercising, nor did I really change my diet, that didn't come until later when my recovery progressed further. Even assuming a decrease in calories consumed when I was in hospital during that week and limited to the hospital food, it would not have been a huge deficit and I ate everything of my meals. The fat loss would not have been 20 pounds or even a large portion of that, the other option is huge amounts of water held do deal with the sodium in my body. So I have no question about water weight being real.
  • earlnabbyearlnabby Posts: 7,473Member Member Posts: 7,473Member Member
    Basically, when people are talking about water weight, they are talking about the temporary gains and losses caused by fluctuations in sodium and carbohydrate consumption, as well as hormone fluctuations in women. The body is really good at maintaining a level of fluids if all other things remain the same. When something gets out of the norm, the body will retain or release fluids. People who eat low carbs, then have a high carb day, will often notice a sudden gain in weight. Since it usually cannot be caused by excess calories (who eats 7000 extra calories in one day to cause a 2 lb fluctuation?) the obvious culprit is fluids. Same thing with eating more sodium than the amount that is your usual. The opposite also happens: cut down on carbs or sodium and you can often see a quick drop in weight.
  • EvgeniZyntxEvgeniZyntx Posts: 24,424Member Member Posts: 24,424Member Member
    I was going to stay out of the forums.

    First off. Glycogen sheathing effect and storage (that 3:1 ratio) has been challenged by some research but remains the "valid theory" it represents about 500 g (a lb) to a kg change in weight possible in liver/muscle/blood during low carb.

    Second, hydration levels along represent a 1.5 kg variation in muscular hydration without entering into dehydration.

    Third volumetric changes in circulation and peripheral blood supply, also due to hydration represent another flux of 500g to 1 kg.

    Fourth, digestion. I'm not sure of these volumes.

    Fifth interstitial osmolarity (the space between cells) can represent up to 2-4kg (or much more but in disease states like diabetes or gout).

    Add to that inflammatory response to exercise and weight training stress which can result in another 1-2kg.
    And I'm excluding processes like lumen absorption and uterine secretory phase of menstruation.

    So, within normal parameters a variation of 4-5 kg are easy within a period of days to weeks.
    "Water weight" can also denote digestive fiber and the associated water mass. Only part of that is low carb glycogen variation.
    edited April 2016
  • klmcneil1klmcneil1 Posts: 26Member Member Posts: 26Member Member
    Second, hydration levels along represent a 1.5 kg variation in muscular hydration without entering into dehydration.

    Third volumetric changes in circulation and peripheral blood supply, also due to hydration represent another flux of 500g to 1 kg.

    Fourth, digestion. I'm not sure of these volumes.

    Fifth interstitial osmolarity (the space between cells) can represent up to 2-4kg (or much more but in disease states like diabetes or gout).

    Add to that inflammatory response to exercise and weight training stress ...

    Thanks for the great detail. Would all of these things be affected in a otherwise healthy person who is fasting or consuming a low-carb diet?
  • klmcneil1klmcneil1 Posts: 26Member Member Posts: 26Member Member
    earlnabby wrote: »
    People who eat low carbs, then have a high carb day, will often notice a sudden gain in weight. Since it usually cannot be caused by excess calories (who eats 7000 extra calories in one day to cause a 2 lb fluctuation?) the obvious culprit is fluids. Same thing with eating more sodium than the amount that is your usual. The opposite also happens: cut down on carbs or sodium and you can often see a quick drop in weight.

    That makes total sense, for a couple of pounds like that. My question is really about when people talk about 10 lbs or more of "water weight" over the first "week or two" of a diet. (Typical example: http://www.livestrong.com/article/404401-does-a-person-lose-water-weight-first-or-pounds-first/ .)That's where it doesn't make sense to me.

    (Assuming the person's healthy and not in an extreme situation like what @rileysowner describes.)

  • klmcneil1klmcneil1 Posts: 26Member Member Posts: 26Member Member
    klmcneil1 wrote: »
    If you're on a low carb diet, your body uses those stores before going the path of gluconeogenesis and ketosis. Liver glycogen for brain function mostly and muscle glycogen for muscle function. You lose water weight.

    Do you have a source that explains that? (Medical or academic)

    "Glucose is stored in limited quantities as glycogen in muscle and liver, and glycogen is converted back into glucose and released into the blood stream as needed. However, as the body does not have vast glycogen stores, a continual dietary source of carbohydrates must replenish these stores. The body will consume its glycogen stores in a matter of 1–2 days. Low-carbohydrate diets, particularly in the initial introductory phase, contain little or no carbohydrate—restricting intake to below 20 g/day. For comparison, the recommended daily allowance (RDA) for carbohydrate is 130 g/day based on the average minimum amount
    utilized by the brain (FNB & IOM, 2002).
    In the absence of dietary carbohydrate and upon depletion of glycogen stores, the body will begin to metabolize body fat into ketone bodies, which can then be used, albeit less efficiently, by the brain and body as fuel. "

    http://ase.tufts.edu/psychology/SPACELAB/pubs/Atkins_Appetite_inpress.pdf

    You use it up but don't consume enough to replenish them.

    Doesn't this prove my point, though? It seems to be saying that you have a small amount of glycogen stores which are depleted in just a day or two, then your body uses your fat stores.
  • rileysownerrileysowner Posts: 7,847Member Member Posts: 7,847Member Member
    klmcneil1 wrote: »
    earlnabby wrote: »
    People who eat low carbs, then have a high carb day, will often notice a sudden gain in weight. Since it usually cannot be caused by excess calories (who eats 7000 extra calories in one day to cause a 2 lb fluctuation?) the obvious culprit is fluids. Same thing with eating more sodium than the amount that is your usual. The opposite also happens: cut down on carbs or sodium and you can often see a quick drop in weight.

    That makes total sense, for a couple of pounds like that. My question is really about when people talk about 10 lbs or more of "water weight" over the first "week or two" of a diet. (Typical example: http://www.livestrong.com/article/404401-does-a-person-lose-water-weight-first-or-pounds-first/ .)That's where it doesn't make sense to me.

    (Assuming the person's healthy and not in an extreme situation like what @rileysowner describes.)

    If I had that much water weight, but with further testing they found no issues with kidney function, then there is a reasonable extrapolation that other people could hold 10 pounds of water weight. Going by what was posted by EvgeniZyntx above could max out at 9Kg (Almost 20 pounds) and the range he gave was 4-5Kg (9 to 11 pounds) which is the exact amount of water weight you are talking about. So yes, water weight is real, even the 10 pounds losses you reference.
  • fitby2012fitby2012 Posts: 167Member Member Posts: 167Member Member
    I don't know much about water weight theory, but I will say that I don't count it out, so to speak. Meaning that those initial losses matter to me. Water weight or not, it is still a bunch of weight that I'm no longer carrying. :smile:
  • EvgeniZyntxEvgeniZyntx Posts: 24,424Member Member Posts: 24,424Member Member
    klmcneil1 wrote: »
    Second, hydration levels along represent a 1.5 kg variation in muscular hydration without entering into dehydration.

    Third volumetric changes in circulation and peripheral blood supply, also due to hydration represent another flux of 500g to 1 kg.

    Fourth, digestion. I'm not sure of these volumes.

    Fifth interstitial osmolarity (the space between cells) can represent up to 2-4kg (or much more but in disease states like diabetes or gout).

    Add to that inflammatory response to exercise and weight training stress ...

    Thanks for the great detail. Would all of these things be affected in a otherwise healthy person who is fasting or consuming a low-carb diet?

    Yes, digestion and interstitial osmolarity (bloating) will be affected by changes in diet.

    Here is away of testing water weight / carb relationship.

    For a week, do a low cal / low carb fast. Say mostly chicken/turkey/shrimp and some veggies at 900 cals or so. Get some vitamins and fish oil supplements. At the end of the week you will have dropped x weight. Drink lots of water, don't over exercise.

    Now, eat that same diet for 3 days but add 300-400 cals of rolls, so you are still under eating but now increased cals to 1200-1300 or so. See what happens. Graph the daily weight through the experiment. Remember that you've actually been in a deficit during the entire time. Personally I saw a 2 lb weight gain doing that.

    +2 lbs while eating 1000 cals under my TDEE.
  • stevencloserstevencloser Posts: 8,917Member Member Posts: 8,917Member Member
    klmcneil1 wrote: »
    klmcneil1 wrote: »
    If you're on a low carb diet, your body uses those stores before going the path of gluconeogenesis and ketosis. Liver glycogen for brain function mostly and muscle glycogen for muscle function. You lose water weight.

    Do you have a source that explains that? (Medical or academic)

    "Glucose is stored in limited quantities as glycogen in muscle and liver, and glycogen is converted back into glucose and released into the blood stream as needed. However, as the body does not have vast glycogen stores, a continual dietary source of carbohydrates must replenish these stores. The body will consume its glycogen stores in a matter of 1–2 days. Low-carbohydrate diets, particularly in the initial introductory phase, contain little or no carbohydrate—restricting intake to below 20 g/day. For comparison, the recommended daily allowance (RDA) for carbohydrate is 130 g/day based on the average minimum amount
    utilized by the brain (FNB & IOM, 2002).
    In the absence of dietary carbohydrate and upon depletion of glycogen stores, the body will begin to metabolize body fat into ketone bodies, which can then be used, albeit less efficiently, by the brain and body as fuel. "

    http://ase.tufts.edu/psychology/SPACELAB/pubs/Atkins_Appetite_inpress.pdf

    You use it up but don't consume enough to replenish them.

    Doesn't this prove my point, though? It seems to be saying that you have a small amount of glycogen stores which are depleted in just a day or two, then your body uses your fat stores.

    And in that day or two you will experience a fast weight loss, as the glycogen is far less energy dense than bodyfat, with about 1 kcal per gram from the 4kcal per gram glycogen + 3 grams of water, compared to the almost 9 kcal per gram of fat.
    Add to that the difference in volume between a maintenance moderate macro diet and a deficit low carb diet and you'll get some extra loss as you have less waste in your bowels on average.

    And the other way around, when you're eating more again and they replenish, you will experience a fast gain.
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