You see it parroted by everyone: drink 8 glasses (64 fl oz) of water a day. Most of those telling you this have heard it from someone who heard it from someone who heard it from someone. Even your doctor likely has no idea whether there are any facts to back this up.
And there aren’t.
Firstly, the research on hydration isn’t about water per se. It’s about all sources of liquid. That includes liquid in the food you eat (perhaps 20% daily) and every other beverage you consume, even coffee.
Secondly, the research bases its suggestions on:
- median intakes
- of general healthy adults
- living in temperate climates
- who are adequately hydrated
As they do with many recommendations, authorities — and those who want to sound like authorities — say drink more water, since more can’t hurt, right? Like saying eat more vegetables and fruits, because no one can overdo that either, right? Only many recommendations ARE hurting us.
Over-hydration is creating conditions like hyponatremia and rhabdomyolysis, and it’s even killed young athletes who are being pushed by authorities like the the American College of Sports Medicine to drink even when they’re not thirsty. (As for vegetables and fruits, many of us can overdo vegetables and fruits, despite what the “experts” tell us, and you’ll know when you have bloating and gas, heartburn, indigestion, IBS, or can’t lose that last 10 pounds though you only snack on “healthy” fruits.)
For the details on hydration recommendation, visit Dietary Reference Intakes : Electrolytes and Water at the National Academies of Sciences, Engineering, and Medicine. Their disclaimer makes it practically meaningless to aim at 8 glasses of water (emphasis below is mine):
Recommended intakes for water are based on median intakes of generally healthy individuals who are adequately hydrated; individuals can be adequately hydrated at levels below as well as above the AIs provided. The AIs provided are for total water in temperate climates. All sources can contribute to total water needs: beverages (including tea, coffee, juices, sodas, and drinking water) and moisture found in foods. Moisture in food accounts for about 20% of total water intake. Thirst and consumption of beverages at meals are adequate to maintain hydration.
#diet #nutrition #hydration #waterconsumption #8glasses