What is a common side effect of low-carbohydrate diets in the initial phases?

The common side effect of low-carbohydrate diets in the initial phases is the loss of water weight. This occurs because carbohydrate storage in the body is tied to water; specifically, for every gram of glycogen (the stored form of carbohydrates) that the body retains, it holds onto approximately 3 grams of water. When carbohydrate intake is significantly reduced, glycogen stores deplete, resulting in the release of this associated water. This rapid loss of water weight can lead to an initial drop in scale weight, which is often observed by individuals starting a low-carb diet.

This effect is temporary and should be distinguished from fat loss, as it primarily reflects changes in water balance rather than significant changes in body composition. Understanding this phenomenon is crucial for those following low-carbohydrate diets, as they might misinterpret the initial weight loss as fat loss, when in reality, it is largely due to fluid changes in the body.