“Drink at least 8 glasses of water each day”. This commandment began with a misunderstood suggestion from the U.S. Food and Nutrition Board in 1945 that we drink 2.5 liters of water a day. Somehow the very next sentence in that report, “Most of this quantity is contained in prepared foods” was overlooked, but it was too late. Fast forward to today and we find half of college kids carrying water bottles wherever they go. This has sold a lot of water bottles, and now some fitness trackers track glasses of water as well. So now there is a force of orchestrated ad campaigns perpetuating the “8 glasses a day” myth.

We might have predicted that water would be monetized, of course, because it’s much easier to get folks to buy something they’ve been primed to believe they need, and the “8 glasses a day” myth was already in the air, ripe for pushing products. The need to “sell more water” has been pushed to the breaking point by the Nestle Waters company which funded a study claiming that two-thirds of children in Los Angeles weren’t getting enough water. Unfortunately, this study used a definition of “dehydrated” that no doctor or physiologist would accept; by simply redefining “adequate hydration” this study ensured that most children would be “dehydrated”. On its face this claim is silly: The thirst reflex in humans, and really all animals, is powerful and precise exactly because dehydration is so detrimental. Why would children, who’ve been successfully looking after their own state of hydration for 300 million years suddenly start getting it wrong in Los Angeles?