
Milk Hydration Edge: It Keeps You Hydrated Longer Than Water—But It's Not a Daily Swap
Milk can keep the body in positive fluid balance longer than plain water in short-term tests due to its mix of electrolytes and macronutrients that slow gastric emptying and promote fluid retention. Multiple trials, including 2007 and 2016 studies, show milk beverages reduce urine output and have a higher hydration index than water, with milk permeate potentially performing even better. However, the hydration advantage appears only in the hours after drinking and comes with a high calorie cost (more than 1,000 calories per serving), making it impractical for everyday hydration. Water remains the recommended default for routine hydration, while milk may be useful for post-exercise recovery or specific needs.











