Plain water has no calories. It provides fluid, but it does not contain sugar, fat, protein, or alcohol, which are the nutrients that add energy to drinks.
Calories appear when something is added to water, such as sugar, syrups, juice, milk, alcohol, or other calorie-containing ingredients. This is why plain tap water, bottled water, and many unsweetened sparkling waters are considered non-caloric, while sweetened drinks can add calories quickly.
Choosing water instead of sugary drinks can help lower daily calorie intake. Research in the provided material shows that people who drink plain water instead of sugar-sweetened beverages often consume fewer calories from drinks overall.
Flavored waters can vary, so it is worth checking the nutrition label. Some have no calories, while others contain sweeteners or added ingredients that provide energy. For general health, plain water and unsweetened drinks are better everyday choices than sugary drinks.
People with medical conditions that affect fluid needs, such as kidney, heart, or digestive problems, should ask a doctor or registered dietitian how much fluid is right for them.