Water is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms. It is vital for all known forms of life, even though it provides no calories or organic nutrients.

Does water really have no calories?

Plain water is calorie-free. Calories come from three nutrients in your diet — carbs, fats, and proteins. Alcohol — while not considered a nutrient — contributes calories as well. Plain water is devoid of these nutrients and thus contains no calories.

Why is there no calories in water?

The three main nutrients that account for our daily calorie consumption are protein, fats and carbohydrates. It is known that one gram of fat, protein and carbohydrate accounts for nine, four and four calories each respectively. Since water is void of carbohydrates, proteins or fats, it does not have any calories.