The paper did not suggest that that is the amount you should be drinking. It had based the adequate daily fluid intake on the median total water intake from US survey data. “In this setting, the AI should not be interpreted as a specific requirement.” AI (Adequate daily fluid intake). “… on a day-to-day basis, fluid intake, driven by the combination of thirst and the consumption of beverages at meals, allows maintenance of hydration status and total body water at normal levels.”. Just drink when you are thirsty and you should be fine. But you do you.