According to a report in the British Medical Journal, it is not necessary to drink 8 glasses of water a day for good health. Scottish doctor Mary McCartney calls this recommendation "nonsense" and cites that there are no clear studies or convincing evidence to support this claim made by the organization Hydration for Health.
I don't know about you, but I drink more than eight glasses of water a day, especially in the summer. Of course, in the back of my mind I have that "eight glasses a day" thing, but I also find water to be the best thirst quencher. I also prefer to drink water with my meals rather than soda, juice, or coffee. This is a personal preference, but I know as I drink water I always think it is a healthier practice than imbibing drinks loaded with sugar or caffeine.
McCartney points to the motives behind Hydration for Health's call to drink water and notes that they are supported by the French company Danone, which just so happens to own Evian, Volvic, and Badoit water bottlers. Obviously, it is no coincidence that this group promotes good health through water.
I am sure if Pepsi and Coca-Cola supported some group to tout the benefits of drinking soda, we would all see it as a sham, but since water equals healthy in most people's minds, we don't think twice about it.
Dr. McCartney is not suggesting we stop drinking water, and she does note that drinking more water can be a good thing for patients who have a need for it, like "those with current kidney stones or polycystic kidney disease." She also notes that the eight glasses theory doesn't make sense for everyone; children and the elderly certainly will not need to drink as much as adults and so on.