If we completely fast for a day or two, weight loss would certainly be rapid and this fact is encouraging for "crash dieters." However, the composition of the weight loss may not be as expected. As much as 60 to 70 percent of that weight loss might be attributable to water loss. Meanwhile, much of the remaining weight loss would be carbohydrate, and to a lesser degree, fat and protein. Keep in mind that glycogen stores bind water. As mentioned earlier, scientists estimate that every gram of glycogen sponges about three grams of water. So during that fasting period when liver glycogen is broken down for energy, water will move out of liver cells into our blood, circulate to our kidneys, and be urinated out. This process makes the scale go down rapidly as the loss of a half of glycogen would lead to about 2 pounds of total weight loss.
Was this article helpful?