We’ve all been told we need to drink at least 8 glasses of water a day in order to maintain healthy daily fluid levels. It is also common knowledge that if we failed to consume any water for about 3 days, we would die.
Why is it then, that so many around us, who are clearly failing to meet these requirements, seem very much alive and well?
While it is true that we can only survive a short while without water, daily requirements vary greatly, depending on several factors – your environment, and your energy output. Given these considerations, the ‘average’ adult loses approximately 2.5L of water per day through normal bodily functions (including breathing, urinating, bowel movements and sweating). Therefore, it is essential that we are at least replacing this lost amount of fluid.
You could correctly assume that the best way to meet this requirement would be to drink water. However, this can be quite challenging for a lot of people. Luckily, most fruits and vegetables are made up of about 90% water, while many meat products contain about 50% water. All of which, our bodies happily utilize and count towards our daily fluid requirements.
It has often been debated that drinking tea and coffee is not an acceptable source of water, given its diuretic nature. This is in fact, not the case. The general formula for calculating how much fluid may be lost by drinking a cup of tea or coffee is as follows:
For every 1 mg of caffeine, there is a water loss of about 1.1mL.
Therefore, if the average 240mL mug of black coffee contains about 70mg of caffeine, then you still have a positive overall intake of water.
Therefore, if the average 240mL mug of black coffee contains about 70mg of caffeine, then you still have a positive overall intake of water.
So rest assured that although drinking water is highly recommended, provided you have a healthy diet of fruit and vegetables, and are consuming regularly beverages throughout the day; you should not have any trouble meeting your daily requirements.
Whitney, E., Rady Rofles, S., Crowe, T., Cameron-Smith, D., Walsh, A., 2014, 2nd Ed., Understanding Nutrition, Cengage Learning Australia, South Australia
ibid
Jaime Talevska, ND