Q. How exactly does the yo-yo effect work? I'm curious why the weight always seems to come back.

Many people experience the frustration of rapid weight regain after extreme fasting, which often leads to dizziness and a decline in quality of life. This happens because the body is remarkably conservative regarding its energy reserves. In Western medicine, this is explained by the 'Set Point' theory—the brain's target weight. When this point is forced down too quickly, the body triggers a survival mode to conserve energy, initiating the yo-yo cycle. From the perspective of Traditional Korean Medicine (TKM), this is viewed as an imbalance of Qi, specifically a state of Spleen Deficiency (脾虛). When the Spleen's function is weakened, the body's efficiency in converting food into energy drops significantly. If this is compounded by 'Dam-eum' (痰飮, accumulated phlegm-fluid/metabolic waste) or 'Eohyeol' (瘀血, blood stasis/stagnation), the overall metabolic capacity collapses. This creates a constitution where weight is gained even with minimal intake. The key to preventing the yo-yo effect is not simply eating less, but restoring and elevating metabolic efficiency. By reassuring the body that it is no longer in a state of starvation and resolving the stagnation of Qi and blood, you can establish a healthy, sustainable weight loss.