A new study found milk, which is made up of 85% water, to be even more hydrating than plain water due to its nutrient-rich composition. The fat, protein, and small amounts of sugar help slow the emptying of fluid from the stomach, keeping the body hydrated longer. – WTF Fun Facts
Source: https://www.nevadamilk.com/milk-found-to-be-more-hydrating-than-water/