The "eight cups rule" may come from two sources.

 

First, in 1945, the American Food and Nutrition Association recommended that people consume 1 millilitre of water for every calorie of food. Considering that ordinary people consume about 1900 calories a day, they need 1.9 liters of water at the same time. Close to 64 ounces;

 

Second, in 2007, Aaron E Carroll and Rachel C Vreeman wrote that American nutritionist Derek? Sterl once encouraged "people should drink at least 6 to 8 glasses of water every day" without any scientific basis.

 

In fact, both the American Food and Nutrition Association's proposal in 1945 and Sterl's statement include water in food and drink. In 2008, Negoianu and goldfarb reviewed the data in the Journal of American Nephrology Society, and concluded that "there is no clear evidence that drinking more water is beneficial". In fact, in 2004, the American Food and Nutrition Association reviewed the issue of water consumption and raised the recommended amount to 91 ounces (2.7 liters) for women and 125 ounces (3.7 liters) for men. Of course, this still includes water in various foods and drinks. Then, besides eating, how much water should a healthy person drink every day? They suggested that "you only need to judge whether you are thirsty or not".