Is Cold Water Contain Calories? Debunking the Myth

December 6, 2025 •

3 min read

According to the U.S. Centers for Disease Control and Prevention (CDC), plain water is calorie-free, making it an excellent choice for staying hydrated and reducing overall caloric intake. While a persistent myth suggests that drinking cold water adds calories or even fat, the truth is grounded in basic chemistry and nutritional science.

Quick Summary

Pure water, regardless of its temperature, contains no calories because it lacks the macronutrients the body uses for energy. The myth that cold water causes weight gain is scientifically unfounded, as the minimal energy burned to warm the water is negligible. This article clarifies the science of calories, hydration, and why all plain water is a zero-calorie beverage.

Key Points

Water is Calorie-Free: Regardless of its temperature, pure water contains zero calories because it lacks the macronutrients (carbohydrates, proteins, fats) your body uses for energy.
Temperature Doesn't Add Calories: The temperature of water does not change its chemical composition. It remains H₂O, incapable of providing usable energy.
Metabolic Boost is Insignificant: While your body expends a small amount of energy to warm cold water to body temperature, the caloric effect is minimal and not a meaningful weight-loss strategy.
Added Ingredients are the Calorie Source: Any calories found in a water-based drink come from added sugars, flavorings, or other ingredients, not from the water itself. Always check nutrition labels.
Focus on Hydration: The most important health consideration is staying hydrated with plenty of plain water, rather than worrying about its temperature.

Understanding What a Calorie Is

To understand why cold water contains no calories, it's essential to first grasp what a calorie actually is. A calorie is a unit of energy, and food calories represent the amount of energy your body can extract from the food you eat. The body gets this usable energy by breaking down macronutrients: carbohydrates, fats, and proteins.

Carbohydrates: Provide approximately 4 calories per gram.
Proteins: Also provide about 4 calories per gram.
Fats: Are the most energy-dense macronutrient, providing around 9 calories per gram.

Water (H₂O) is a simple molecule composed of two hydrogen atoms and one oxygen atom. It contains none of these macronutrients. This means that from a nutritional standpoint, water simply has no chemical fuel for the body to metabolize and turn into energy, regardless of its temperature.

The Cold Water and Metabolism Myth

The myth that cold water is somehow more caloric or causes weight gain likely stems from a misunderstanding of how the body regulates temperature. When you drink cold water, your body does expend a small amount of energy to warm it up to your core temperature of around 98.6°F (37°C). This process is known as thermogenesis. While technically a calorie-burning activity, the effect is so minimal it is practically insignificant for weight management.

For example, studies suggest that drinking 500 milliliters (about 17 ounces) of cold water might temporarily increase your resting energy expenditure by a tiny amount, burning perhaps 4–7 extra calories. This is an amount equivalent to a few sips of a sugary drink, not a meaningful contributor to weight gain or loss. Focusing on overall diet and exercise has a far greater impact on weight management than the temperature of your water.

Comparing Cold vs. Room Temperature Water for Health

While both cold and room-temperature water are equally hydrating and calorie-free, they do offer slightly different physiological effects that are important to distinguish.


Feature	Cold Water	Room Temperature Water
Body Cooling	More effective for lowering core body temperature, especially during or after exercise.	Less immediate cooling effect, gentler on the system.
Digestion	Can cause blood vessels in the stomach to constrict, potentially slowing down digestion for some individuals.	Allows for smoother and quicker absorption of fluids by the body.
Alertness	The invigorating sensation can boost mental alertness and wakefulness.	Soothing and easier on sensitive throats or teeth.
Thermoregulation	Body must expend a tiny amount of energy to warm it up.	No significant energy expenditure required for warming.

The Hydration Imperative

The temperature of your water is far less important than ensuring you drink enough of it. Proper hydration is critical for virtually every bodily function. Adequate water intake helps to:

Maintain normal body temperature.
Lubricate and cushion joints.
Protect the spinal cord and other sensitive tissues.
Get rid of waste through urination, perspiration, and bowel movements.
Transport nutrients to your cells.
Aid in proper digestion.

Choosing plain water over sugary drinks like soda or juice is one of the easiest ways to reduce your daily calorie intake. Flavoring water naturally with slices of lemon, cucumber, or mint is an excellent calorie-free way to make it more appealing without adding sugars.

The Real Culprits: Added Sugars and Flavors

While pure water has no calories, many commercially available 'water' products do. Tonic water, flavored waters with added sugars, and vitamin-enhanced drinks can contain a significant number of calories. Always check the nutrition label for ingredients and added sugars. For instance, a 12-ounce serving of tonic water can contain over 100 calories from sugar. These are the actual sources of calories people might mistakenly associate with water itself.

Conclusion

To put it simply, no, cold water does not contain calories. The number of calories in plain, unflavored water—whether hot, cold, or room temperature—is zero. Calories come from macronutrients like carbohydrates, proteins, and fats, which water does not contain. While your body does burn a tiny, negligible amount of energy to warm cold water, this effect is insignificant for weight management. The most important health takeaway is to stay adequately hydrated by drinking plenty of plain water, choosing it over high-calorie sugary beverages. The myth that cold water adds calories is a harmless one, but understanding the real science empowers you to make informed decisions about your health and nutrition.

For further reading on the science of calories and nutrition, a reliable resource is the U.S. National Institutes of Health.

Frequently Asked Questions

Cold water has no calories because it is a simple chemical compound (H₂O) that contains no carbohydrates, fats, or proteins, which are the sources of calories.

No, drinking cold water does not cause weight gain. Weight gain occurs when you consume more calories than you burn, and cold water has zero calories.

The body does burn a tiny, insignificant amount of energy to warm cold water. This effect, known as thermogenesis, is too small to be a factor in weight loss.

In nutrition, a calorie refers to usable energy from macronutrients. While hot water contains more thermal energy than cold water, this energy cannot be used by the human body for metabolism.

It depends on the type. Plain flavored waters (with natural flavors but no sugar) are typically calorie-free, but check the label, as many commercial flavored and vitamin-enhanced waters contain added sugars and thus have calories.

Both temperatures are healthy. Some people find room temperature water easier on digestion, while cold water is more refreshing during exercise. The best temperature is a matter of personal preference and context.

For pure tap, bottled, mineral, or sparkling water without added sweeteners or flavors, the calorie count is zero. The easiest way to be certain with any packaged drink is to read the nutrition label.