Coconut water is the clear fluid inside coconuts. It's not the same as coconut milk, which is a blend of coconut water and grated coconut.

So coconut water is a type of juice. Unlike other juices, unflavored coconut water is low in sugar and calories.

Coconut water is popular for rehydration after exercise or during mild illness. It's true that coconut water has electrolytes, such as potassium, sodium and manganese. The amounts vary by brand.

Some evidence suggests that coconut water is comparable to sports drinks. But it's no more hydrating than plain water.

As a casual beverage, coconut water is considered safe. Coconut water does have calories — 45 to 60 calories in an 8-ounce serving. Weighing the pros and cons, plain water is still the smart choice.