"It's a fad"

Hydration has become a look. People carry two-litre bottles with encouraging phrases printed at intervals down the side. There are electrolyte sachets for sitting at a desk, and reminders on watches, and a general sense that drinking water is something done ostentatiously by people with more time than you. The belief that follows is that the whole thing is marketing, and that a sensible person ignores it.

I think the sensible person is half right. The bottle culture is marketing, and most of what it sells is unnecessary. Barry Popkin, Kristen D'Anci and Irwin Rosenberg reviewed water and health in 2010 and were plain that there are major gaps in knowledge about how much people need, no long-term randomised trials, and little to support precise targets. Nobody has shown that two litres beats six cups for a person at a desk. The sachets are for people who've been sweating for hours, not for people who've been in a meeting. The watch reminding you to drink at eleven forty is a nuisance.

But the fad has grown around a small, dull truth, which is the one in chapters 6 and 8. Mild dryness makes people tired and headachy and less able to concentrate, and drinking enough that your pee is pale stops that. The truth doesn't need a bottle with times on it. It needs a glass next to the kettle. The fad has made the truth look like a lifestyle, and the reaction against the fad has thrown the truth out with it.

The honest objection is that "a glass next to the kettle" is also advice, and you've had enough advice. What I'd say is that this advice is smaller than the fad in every direction. Less water, no equipment, no target, no app. Six cups of whatever, most of them things you already drink, checked by the colour in a bowl you were going to look at anyway.

I'd put it this way. The fad is a way of doing an ordinary thing in a way that shows. The dry day is a way of not doing it at all. Between them is the ordinary thing done quietly, and that's where this book is.