A new “beverage hydration index” provides evidence-based suggestions for how to most efficiently hydrate. The index was developed from a British study published in December that tracked how long 13 common beverages remain in the body after being consumed.
The British study determined the hydration index of 13 common beverages by having the participants, 72 males in their mid-20s, drink a liter of water as the standard beverage.
The results showed that four beverages — oral rehydration solution, like Pedialyte; fat-free milk; whole milk and orange juice — had a significantly higher hydration index than water.