Milk, certain fruits and vegetables, and a handful of other beverages all contribute meaningfully to your daily hydration. About 19% of your total water intake already comes from food, and many common drinks hydrate just as well as, or even better than, plain water. The National Academies recommend about 3.7 liters of total water per day for men and 2.7 liters for women, and that total includes everything you eat and drink, not just glasses of water.
Milk Hydrates Better Than Water
In studies measuring how long beverages keep the body hydrated, milk consistently outperforms plain water. Researchers developed something called a Beverage Hydration Index to compare how well different drinks maintain fluid balance over several hours. Skim milk and whole milk both scored higher than water, with whole milk performing roughly equal to oral rehydration solutions, the medical products specifically designed to treat dehydration.
The reason comes down to what’s in milk. It contains sodium, potassium, and a natural balance of carbohydrates and protein that slows gastric emptying, meaning fluid leaves your stomach more gradually and gets absorbed over a longer window. When you drink plain water, your body processes it quickly, and your kidneys flush out the excess relatively fast. Milk’s nutrient density keeps that fluid circulating longer. This makes it a particularly strong option after exercise, when your body needs to replenish both fluids and electrolytes.
Other Beverages and How They Compare
Orange juice performs about as well as water for hydration, and at some time points slightly better, likely because of its natural sugars and potassium content. That said, most other common beverages tested, including sports drinks, tea, coffee, cola, and diet cola, actually scored slightly worse than water on the hydration index. They still contribute fluid, but your body doesn’t retain it as efficiently.
Coconut water is another popular option. A cup contains about 470 mg of potassium and 30 mg of sodium. That potassium level is significantly higher than most sports drinks, but it’s actually lower in sodium and sugar than what athletes typically need for post-workout recovery. For everyday hydration, though, coconut water works well as a flavorful alternative, especially if you find plain water boring.
The key mechanism behind all of this is straightforward: sodium helps pull water into your cells, and when glucose is present alongside sodium in your gut, a specific transport protein moves both into the cell together, with water following passively. This is why beverages containing some combination of salt, sugar, and protein tend to hydrate more effectively than plain water alone.
High-Water Foods That Count Toward Your Intake
Food accounts for roughly one-fifth of your daily water intake, and certain fruits and vegetables are almost entirely water by weight. The most hydrating options:
- Cucumber: 96% water
- Iceberg lettuce: 96% water
- Celery: 95% water
- Radishes: 95% water
- Tomatoes: 94% water
- Zucchini: 94% water
- Watermelon: 92% water
Eating a large salad or snacking on watermelon contributes a meaningful amount of fluid. A two-cup serving of diced watermelon, for instance, delivers roughly the same volume of water as a small glass. These foods also come with fiber, vitamins, and minerals, so they pull double duty. Soups and broths work similarly, combining liquid with sodium that helps your body hold onto the fluid longer.
What Actually Matters for Staying Hydrated
You don’t need to obsess over choosing the perfect beverage. The most practical approach is variety: drink what you enjoy, eat plenty of produce, and pay attention to your body’s signals. Urine color is the simplest way to check. Pale yellow (straw-colored) means you’re well hydrated. Medium yellow suggests you need more fluids. Dark yellow or amber, especially in small amounts with a strong smell, signals that you should drink a large glass of water right away.
A few things to keep in mind when choosing alternatives to water. Fruit juice and coconut water contain calories and sugar, so they’re best as part of your overall intake rather than your primary fluid source. Milk is excellent for hydration but obviously isn’t practical to sip throughout the day the way water is. Coffee and tea, despite mild diuretic effects, still contribute a net positive amount of fluid. The old advice that caffeine dehydrates you has been largely overstated for moderate consumption.
If you’re exercising intensely for more than an hour, or sweating heavily in hot weather, drinks with both sodium and some sugar will help you retain fluid better than water alone. For most other situations, the best hydration strategy is simply the one you’ll actually stick with. If adding cucumber slices, switching to sparkling water, or having a glass of milk with meals helps you drink more, that counts.