Benjamin Franklin said, "When the well is dry, we know the worth of water." Every part of the human body requires water - every day and for every function. Water is so critical to human life that most diets recommend increasing water intake as a means of increasing weight loss. There is increasing evidence that drinking water does help increase metabolism resulting in faster weight loss. But what about drinking cold water? Does drinking cold water burn calories? Does it increase the metabolism even more - causing even faster weight loss?
Does Drinking Cold Water Burn Calories?
A calorie is actually a unit of heat. One calorie is formally defined as the energy required to heat one gram of water by one degree Celsius. But wait. There is also the concept of a Calorie (with a capital C). THIS Calorie is what is usually found on food labels. And this Calorie actually equals 1000 calories (with a lower case "c" - also called a kilocalorie). So, a can of your favorite cola beverage that is labeled as containing 200 Calories actually contain 200,000 regular calories (kilocalories)!
But don't worry. The same definition also applies to burning calories. If you burn one Calorie (capital "C"), you are burning 1000 calories (lower case "c"). The distinction is important because the definition of calorie is based on the lower case "c" calorie. That is, one calorie is still the energy required to heat one gram of water one degree Celsius. This definition would support the idea that drinking cold water should result in weight loss. But, is this true?
Actually, the truth is that drinking cold water may result in weight loss. Say for example, that you drink 16 ounces (or about 470 grams) of ice water at a temperature of 0 degrees Celsius. Since your body temperature is around 37 degrees Celsius, this means that your body will raise the temperature of those 470 grams of water by 37 degrees. In this process, your body will burn 17,390 calories (lower case "c") or 17.39 Calories (with the upper case "C"). Not a whole lot of Calories - or weight loss. However, if you drink the recommended 64 ounces of cold water each day (4 of those 16 ounce glasses); you will burn nearly 70 Calories each day.
In a study in the International Journal of Obesity, researchers found that resting energy expenditure (REE) increased in overweight children after drinking cold water. REE is defined as the number of calories required to maintain the body when at rest. The theory is that if REE can be increased, more calories can be burned. The researchers suspect that this is because drinking the cold water may actually cause normally inactive muscles to become active on a metabolic level -- even without increasing movement. This study found that REE actually dropped in the first few minutes after drinking cold water. However, after that initial drop, REE started to increase until it peaked after 57 minutes. And at that peak, resting energy expenditure had increased by 25 % over the initial level.
Obviously, you will not lose much weight just by drinking cold water, but when added to an exercise program and better eating habits, you will begin to notice weight loss.
Warnings for Drinking Cold Water
There are risks and benefits from drinking cold water. The human body is an amazing thing with checks and balances built in to keep everything functioning smoothly. Water is the way this happens. Drinking cold water can increase weight loss by burning more calories while allowing the body to get rid of toxins and transport nutrients into the cells. And, if you are relatively healthy, the benefits of drinking cold water typically outweigh the risks.
However, it IS possible to drink too much water! Before you go out and drink hundreds of ounces of water each day, you should understand that there may be risks from drinking too much water. Water intoxication or poisoning happens when the electrolytes in your body (particularly sodium) are washed out. Drinking too much water can remove too much sodium without allowing the body a chance to replace it. Water intoxication is most often seen when an inexperienced person begins to exercise. The novice drinks water to replace the water being lost through sweats - but forgets to replace the electrolytes also being lost! That's why experienced athletes consciously replace their fluids AND electrolytes during exercise. Drinking too much water can cause an increase in water in the brain causing cerebral edema. Cardiac rhythm disturbances can also occur as the potassium levels decrease. These risks can be avoided by working with your healthcare provider to be sure you are replacing electrolytes as you increase your water intake.