Science Explains Why You Lose Water Weight

Science Explains Why You Lose Water Weight New dieters, especially if theyre eating a low carb diet, see a dramatic initial weight loss ranging from four to 12 pounds in the first week. The initial loss is exciting, but it quickly slows to one or two pounds per week. Youve probably heard this early weight loss is water weight, rather than  fat. Where does water weight come from and why does it drop before fat? Heres the scientific explanation. Key Takeaways: Water Weight Loss On a low carbohydrate diet, the body turns to glycogen as an energy source after it expends glucose. Quick water weight loss occurs when metabolizing glycogen because the process requires water.Eating or drinking excess electrolytes can lead to water retention because the body keeps the water to maintain a set electrolyte balance as part of homeostasis.Dehydration can also lead to water retention. In this situation, the body acts to conserve water when its not being replenished. The Source of Water Weight The early weight loss from a diet can be partly fat, especially if youre exercising and reducing calories, but if youre using more energy than youre replacing as food and drink, the first weight youll lose will be water. Why? Its because the energy source your body turns to once it runs out of its relatively small store ​of ​carbohydrates (sugars) is glycogen. Glycogen is a large molecule made up of a protein core surrounded by glucose subunits. Its  stored in the liver and muscles for use during energy-intensive activities, like running away from danger and supporting the brain when food is scarce. Glycogen can be quickly metabolized to meet the bodys need for glucose, but each gram of glycogen is bound to three to four grams of water. So, if you use up your bodys glycogen stores (as when dieting or with prolonged exercising), a lot of water is released over a short amount of time. It only takes a few days of dieting for glycogen to be expended, so the initial weight loss is dramatic. Loss of water can lead to loss of inches. However, as soon as you eat enough carbohydrates (sugars or starches), your body readily replaces its glycogen stores. This is one reason people often see an initial weight gain immediately after going off a diet, particularly if it was one that restricted carbohydrates. Its not the fat coming back, but you can expect all the water you lost the first couple of days of a diet to return. Other Causes of Water Weight Changes There are many biochemical reactions in the body that affect how much water is stored or released. Natural hormonal fluctuations can have a big impact on water storage. Since the body maintains stable electrolyte levels, losing too much of an electrolyte can leave you dehydrated, while too high of intake can cause you to retain water. Diuretics are chemicals that prompt the release of water. Natural diuretics include any stimulant, such as coffee or tea. These chemicals temporarily alter the natural set point for water retention, causing slight dehydration. Alcohol also acts as a diuretic, potentially causing much greater dehydration because additional water is used to metabolize ethanol. Eating too much sodium (as from salt)  leads to water retention because water is needed to dilute the high level of the electrolyte. Low potassium, another electrolyte, can also cause fluid retention because potassium is used in the mechanism that releases water. Many medications also affect water homeostasis, potentially leading to water weight gain or loss. So do some supplements. For example, dandelion and stinging nettle are natural diuretic herbs. Because water is used for thermoregulation, heavy perspiration, whether it be from exertion or sweating in a sauna, can produce temporary weight loss from dehydration. This weight is immediately replaced after drinking water or other beverages or eating foods that contain water. A surprising cause of water retention is mild dehydration. Because water is critical to so many processes, when its not being replenished at a fast enough rate, conservation mechanisms kick in. Water weight wont be lost until adequate water is being consumed and normal hydration is achieved. After that point, research indicates drinking more water doesnt aid weight loss. Nutrition expert Beth Kitchen (the University of Alabama at Birmingham) conducted research that concluding drinking more water does burn a few more calories, but it wasnt a significant number. Her research also indicated drinking ice-cold water as opposed to room temperature water resulting in an insignificant difference in calories burned and weight lost.