Calories in Water: Nutritional facts (Carbs, Fiber, Protein, Fat) for Water Types

One hundred milliliters (100mL or 3.4 fl oz) of plain water contains 0 calories. This applies to general bottled water, tap water, purified water, distilled water, Nestlé Pure Life, Evian, and Dasani.

One liter (1000mL or 33.8 fl oz) of plain water contains 0 calories. This applies to general bottled water, tap water, purified water, and distilled water.

One glass of plain water contains 0 calories.

Water is essential for life and provides numerous health benefits, which are crucial for nearly every bodily function. The health benefits of water are listed below:

• Supports Physical Performance: Adequate hydration is vital for maintaining physical performance, especially during exercise. Dehydration can lead to reduced endurance, increased fatigue, and altered body temperature control. A review by Sawka MN et al. (2005), "Human water needs," underscores the importance of hydration for physiological function and performance.
• Aids Digestive Function: Water helps break down food so that your body can absorb the nutrients. It also softens stool, which helps prevent constipation. Insufficient water intake is a common factor contributing to constipation. (National Institute of Diabetes and Digestive and Kidney Diseases. Constipation.)
• Essential for Kidney Function: Kidneys use water to filter waste products from the blood and excrete them in urine. Adequate water intake helps the kidneys function efficiently and can help prevent kidney stones by diluting the concentration of minerals that can form stones. (Clark WF, Sontrop JM., 2010. Effect of HMG CoA reductase inhibitors on kidney function: a systematic review and meta-analysis of randomized trials.) While this study is on statins, kidney function literature broadly supports hydration's role.
• Regulates Body Temperature: Water helps regulate body temperature through sweating and respiration. When the body heats up, water is released as sweat, which cools the body as it evaporates. (Havenith G., 2001. Temperature regulation, heat balance and clothing.)
• Supports Brain Function and Mood: Even mild dehydration can impair cognitive functions such as concentration, alertness, and short-term memory. Staying hydrated is linked to improved mood and reduced frequency of headaches. A study by Armstrong LE et al. (2012), "Mild dehydration affects mood in healthy young women," demonstrated negative effects of dehydration on mood and cognitive symptoms.
• Promotes Cardiovascular Health: Water is a major component of blood volume. Proper hydration helps maintain blood volume, which supports healthy blood pressure and circulation, ensuring oxygen and nutrients are delivered efficiently throughout the body. (American Heart Association. Staying Hydrated - Staying Healthy.)
• Helps Maintain Skin Health: Adequate water intake contributes to skin hydration and elasticity, although the extent to which it prevents wrinkles is debated. Dehydration can make skin appear drier and less plump. (Palma L, Marques LT, Bujan J, Rodrigues LM., 2015. Dietary water affects human skin hydration and biomechanics.)

While essential, water consumption can have potential downsides under specific circumstances:

• Water Intoxication (Hyponatremia): Drinking excessive amounts of water in a very short period can dilute sodium levels in the blood, leading to a dangerous condition called hyponatremia. This is rare in healthy individuals with normal diets but can occur in endurance athletes or individuals forcing excessive water intake. (Adrogué HJ, Madias NE., 2000. Hyponatremia.) Listening to thirst cues and avoiding rapid overconsumption is key. Daily intake recommendations (around 2.7L for women, 3.7L for men, from all sources) spread throughout the day do not pose this risk.
• Potential Contaminants (Tap Water): While generally safe in developed countries, tap water can potentially contain contaminants like lead (from pipes), chlorine byproducts, pesticides, or microbes if treatment systems fail or infrastructure is old. Using a certified water filter (e.g., NSF certified) can mitigate these risks if concerns exist. Bottled water is an alternative, though it has its own considerations.
• Cost and Environmental Impact (Bottled Water): Bottled water is significantly more expensive than tap water and generates substantial plastic waste, contributing to environmental pollution. Filtering tap water is a more sustainable and cost-effective alternative for improving taste or reducing potential contaminants.
• Lack of Minerals (Distilled/Highly Purified Water): Water treated by distillation or reverse osmosis removes most minerals. While not harmful short-term, relying solely on demineralized water long-term means missing out on trace minerals like calcium and magnesium found in tap or mineral water. Consuming a balanced diet provides necessary minerals, making this less critical for most. Mineral water or tap water are alternatives if mineral intake from water is desired.
• Microplastics: Concerns exist about the presence of microplastics in both bottled and, to a lesser extent, tap water, although the health impacts are still under investigation. (World Health Organization. Microplastics in drinking-water.) Filtering may reduce some microplastics, but research is ongoing.

Yes, water is unequivocally good for you. Water is essential for survival and optimal health. Proper hydration supports virtually every system in the body. It aids digestive health by facilitating nutrient absorption and preventing constipation. Water is crucial for brain health, impacting concentration, alertness, and mood. It enables efficient kidney and liver health by helping flush waste products. Water regulates body temperature, supports cardiovascular health by maintaining blood volume and circulation, keeps joints lubricated, and contributes to skin health. Unlike sugary drinks or many other beverages, plain water provides necessary hydration without adding calories, sugars, or unhealthy fats. While potential issues like contaminants in tap water or the environmental impact of bottled water exist, these relate to the source or packaging, not water itself.

The National Academies of Sciences, Engineering, and Medicine determined adequate daily fluid intake is about 3.7 liters (15.5 cups or 125 ounces) for men and 2.7 liters (11.5 cups or 91 ounces) for women. These figures represent total fluid intake, including water contained in foods (which accounts for roughly 20%) and other beverages. There isn't a separate specific requirement for plain water set by the FDA or Dietary Guidelines, but water is the recommended primary source of hydration. General recommendations for daily water intake vary, and individual needs depend on factors like age, sex, activity level, climate, and overall health.

There isn't a strict upper limit for total daily water intake spread throughout the day for healthy adults, as the kidneys can process large volumes over time. The primary danger comes from drinking excessive amounts of water very rapidly, which can overwhelm the kidneys' ability to excrete it, leading to hyponatremia (water intoxication). Healthy adult kidneys can excrete roughly 0.8 to 1.0 liters (about 27-34 ounces) of water per hour. Consuming significantly more than this within an hour, especially without adequate electrolyte intake (common in some endurance events or water-drinking contests), poses the greatest risk. 

For general hydration throughout the day, exceeding the adequate intake recommendations (3.7L for men, 2.7L for women from all sources) is usually not harmful for healthy individuals, as excess water will be excreted, but forcing massive amounts serves no health benefit and can be dangerous if done too quickly.

Plain, unadulterated water, regardless of its type (tap, spring, purified, distilled, mineral, or sparkling) contains zero calories. The differences between these water types lie in their source, treatment methods, and resulting mineral content or carbonation, none of which contribute calories. Calories are only introduced to water when caloric substances like sugars, syrups, fruit juices, or other flavorings are added, transforming it into a flavored water, juice drink, or soda. Therefore, when considering plain water for hydration, all types listed have the same calorie count: zero. The highest and lowest calorie count for any type of plain water is 0.

The origin of drinking water for humans lies in Earth's natural freshwater sources, primarily surface water (rivers, lakes) and groundwater (aquifers accessed via springs and wells). Early human civilizations invariably settled near reliable water sources. Access evolved from simply collecting surface water to digging wells for groundwater access and constructing sophisticated systems like Roman aqueducts to transport large volumes of water to population centers. 

Ensuring water safety has been a long-standing challenge; historically, contaminated water was a major source of disease. The understanding that pathogens in water caused illnesses like cholera emerged significantly in the 19th century, driving the development of water treatment methods. Early purification involved boiling or rudimentary filtration. Modern municipal drinking water systems employ advanced multi-stage treatment, including filtration and disinfection (using chlorine or UV light), to provide safe tap water on a massive scale. The bottled water industry later developed, offering consumers choices like natural spring water, mineral water sourced from specific protected underground sources, and purified water treated by processes like reverse osmosis or distillation.