Question: from Melissa
I just read a response of yours to a customer inquiring whether drinking a lot of water would interfere with nutrient absorption. My question is about one of your final comments, “as long as it's not a gallon a day.”
I live in a very dry, hot climate, exercise rather rigorously on a regular basis, and frequently drink a gallon of water a day. Other than my morning cup of coffee, water is pretty much all the liquid I consume. Are you suggesting that there is a problem with drinking this quantity of water?
Answer: from Joanna (Medical Nutritionist for Xtend-Life)
I think that the comment referred to was made a little ‘tongue in cheek’ as a rough guide, and bearing the average person in an average climate in mind, rather than a specific safe cut off for drinking excess. (Comment from Warren! Joanna is correct in that it was a tongue in cheek comment as the amounts each individual needs can vary greatly such as in the case with Melissa. Sorry…I should have been a little more careful and specific)
A gallon of water equates to between 3 1/2 – 4 1/2 litres per day (depending on whether you are using a US or UK gallon measurement). This is a lot of water to drink. However, if this is replenishing a lot of lost fluid during the day this could be acceptable. Also as long as it is being drunk in small portions throughout the day, this is fine.
A person in the right circumstances, as noted above, could potentially drink up to 10-15 litres of water per day. However this is not recommended for the average person as there is a danger of water excess. Drinking too much water, too quickly, can swell brain cells (what is known as water on the brain) and cause head pressure.
As long as it is being drunk in safe quantities, and specifically to replenish fluids you are losing due to heat and activity, you are fine to drink a gallon a day in these circumstances.