The result is a shiny new hydration index, which ranks 13 different liquids -- including sparkling water, cola, orange juice, lager, hot black coffee, full-fat milk, and skim milk -- and at the very least serves as a guide to liquids that won't make you pee every 20 minutes.
What the hell is this hydration index?
Researchers wanted to find out how much water your body absorbs from various drinks, based on several factors: how many carbs and electrolytes are in each drink, the sodium content, and if there’s a diuretic present.
The hydration index attempts to recreate with liquids what the glycemic index does for food, but somewhere along the way the ranking ends up claiming beer is basically on par with sports drinks at replenishing lost fluids. Which is totally fine!