Believe it or not, milk may be more hydrating than water.
A growing body of research suggests that certain beverages—including milk—may be more hydrating than water in certain circumstances.
To reveal fact from fiction, we spoke to two registered dietitians about milk’s hydrating potential. Plus, find out which popular hydrators are expert-approved and discover when milk may help with hydration—and when it may not.
Studies show that milk may hydrate better than water due to its electrolyte, protein, fat, and carbohydrate content. This balance of nutrients and electrolytes reduces the rate of gastric emptying, which helps the body retain fluids for longer. However, this doesn’t necessarily mean milk is always better than other popular hydrators, such as water.
“More hydrating doesn’t always mean ‘better for all situations,’” Angel Planells, RDN, a Seattle-based registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics, told Health.
There are certain circumstances when milk is and isn’t the best hydration option. Milk can be a great option for:
- Post-exercise recovery: “Milk can be an excellent hydration option post-exercise, especially after moderate to intense workouts,” Lena Beal, RDN, sports nutritionist, and spokesperson for the Academy of Nutrition and Dietetics, told Health. “Not only does it replace lost fluids, but it also provides high-quality protein for muscle recovery and carbohydrates to replenish glycogen stores.”
- For rehydrating children: “Milk can be useful when there’s a need to restore both fluid and nutrients in populations that may not eat or drink enough,” said Planells. While older adults can also benefit from milk’s rehydrating properties, milk has been found to be most effective as a rehydrator in children.
- To restore mild dehydration: “When someone needs to rehydrate and replenish calories, protein, and micronutrients (such as after a long hike or illness),” said Planells.
While milk can be a great hydrator in certain situations, it isn’t always the best hydration option. These include:
- If you need to eat a low-calorie diet: For low-calorie hydration, water is the better option.
- If you are allergic to dairy or have lactose intolerance: Other types of hydration drinks can be consumed instead for those with milk sensitivities or allergies.
Compared to other popular beverages that provide hydration, milk is an expert-approved choice. Both Beal and Planells recommend it, but in the right circumstances only.
Here’s how experts rank hydrating drinks, from highest to lowest:
- Milk: Drinking milk, especially low-fat milk, helps retain fluid for longer. Plus, it contains a mixture of protein, carbohydrates, water, and electrolytes, which makes milk a good choice for post-exercise recovery.
- Oral rehydration solutions: These are formulated to treat dehydration with an optimal balance of electrolytes.
- Coconut water: High in potassium and low in sodium, Planells says coconut water is great for rehydration after light activity, but it’s not ideal for more intense activity.
- Sports drinks: Sports drinks such as Gatorade replenish electrolytes (such as sodium and carbohydrates) that are lost during or after intense exercise and endurance activities.
- Water: A classic hydrator with zero calories, water’s shortfall is that it does not replace electrolytes that are lost during exercise.
- Juice: While juice contains nutrients and water, it also contains a lot of calories and added sugars.
- Caffeinated beverages: The caffeine in soda, tea, and coffee has a mild diuretic effect, increasing the outflow of pee and decreasing the amount of fluid in the body.
- Alcohol: Alcohol also has a diuretic effect, which decreases fluid retention.
Milk can be a better hydrator than water in certain circumstances, but it’s not always the best choice.
Low-fat milk is an excellent choice for post-exercise recovery or to restore mild dehydration, but if you’re on a low-calorie diet or have lactose intolerance, opt for another hydrating beverage (such as water) instead.
