Marco Crisciotti Studies reveal that milk can hydrate better than water, thanks to its unique composition of electrolytes, proteins, and calories that slow down fluid loss.
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When summer hits hard and the heat becomes relentless, our first instinct is often to reach for an ice-cold glass of water. It feels like the purest, most natural solution to quench our thirst. And that instinct isn’t wrong—drinking plenty of water is essential, especially when temperatures rise. According to the European Food Information Council (EUFIC), we should aim to drink at least 2.6 quarts (2.5 liters) of water a day to maintain a healthy hydration balance. Many of us already do this religiously, keeping a water bottle nearby at all times.
But science, as it often does, complicates the story.
Surprisingly, water may not be the most hydrating beverage out there. Several studies have shown that milk—yes, milk—actually keeps you hydrated better and for longer than water. It sounds counterintuitive at first, but the explanation makes a lot of sense once you dig into it.
The unexpected hydration hero: milk
This idea first gained traction with a British study published in 2007 and archived on PubMed, which looked at how various beverages affected hydration post-exercise. The findings were surprising: milk led to less urine production than water, helping participants stay better hydrated for up to five hours after drinking. By contrast, other drinks—including water—only maintained hydration levels for around an hour.
Fast forward ten years, and researchers at the University of Limerick in Ireland confirmed similar results. Their study found that milk’s unique combination of nutrients—sodium, proteins, and fats—worked together to slow fluid loss from the body. It’s a trio that forms a kind of hydration dream team, especially helpful during scorching July afternoons when our bodies are fighting to stay cool.
In 2016, the American Journal of Clinical Nutrition published a more comprehensive study, testing 13 different beverages on 72 male participants. From beer to tea, from coffee to sodas and juices, the most hydrating drinks turned out to be milk (both whole and skim) and oral rehydration solutions designed for medical use. Water, while still effective, didn’t take the top spot.
Why milk beats water at hydration
What makes milk more hydrating than water? It all comes down to composition. Water, while essential, is a simple liquid—no calories, no electrolytes, no proteins—so it moves quickly through the gastrointestinal tract and is rapidly excreted.
Milk, on the other hand, contains electrolytes like sodium and potassium, as well as calories and proteins, all of which slow down the stomach’s emptying process. This helps the body retain fluids longer, reducing the urge to urinate and ultimately prolonging hydration.
Skim milk, in particular, stands out. It offers electrolytes and calories but without the fat content of whole milk, making it a lighter option for frequent hydration without the heaviness some associate with dairy.
Proceed with caution (and context)
Before you start chugging milk all day, it’s worth noting that none of the studies suggest replacing water entirely. The trials had limitations—relatively small sample sizes, short duration—and milk comes with added calories and nutrients that, while beneficial in some contexts, might not suit everyone’s daily routine.
Water remains the gold standard for everyday hydration. It’s calorie-free, accessible, and precisely what your body needs in most situations. Milk can complement it, especially after a tough workout or during periods of intense heat, when the risk of dehydration spikes.
So… milk or water?
That’s the question, isn’t it? The answer, unsurprisingly, lies in balance. Water should still be your go-to drink, your daily baseline. But milk has earned its place as a hydration booster, perfect for specific moments when your body needs something more substantial than H₂O.
So next time you’re sweating through a brutal heatwave, maybe don’t just think “ice water.” A cold glass of milk could help your body stay hydrated longer, and possibly save you from turning to sugary or carbonated alternatives.
Final thoughts
Water is the cornerstone of hydration, but milk is a surprisingly powerful ally. When the sun is blazing and your body is losing fluids fast, alternating between water and milk might be the most effective way to keep your hydration levels steady—without relying on sports drinks or soda.
So this summer, consider giving milk a second look. Your body might thank you.
