Q. Why do I gain weight back even after a successful diet? I want to know why the 'yo-yo effect' happens.

I understand the frustration; many people try extreme fasting only to feel dizzy and exhausted. It is important to realize that the yo-yo effect is not a failure of willpower, but a survival instinct. From a conventional medical perspective, sudden low-calorie diets drop your basal metabolic rate. Your body adapts to survive on less energy, and once you resume normal eating, it stores fat more aggressively to prepare for the next perceived famine. In Traditional Korean Medicine (TKM), this is viewed not merely as a calorie issue, but as a 'decline in bodily function.' Specifically, when Spleen Deficiency (Bi-heo, 脾虛) occurs, the body cannot properly transport nutrients, leading to the accumulation of waste. When this is coupled with Blood Stasis (Eo-hyeol, 瘀血) and Phlegm-Fluid (Dam-eum, 痰飮), the overall metabolic flow becomes obstructed. Essentially, this is like trying to move a car by pushing it manually while the engine (metabolic function) is broken. To achieve sustainable weight loss, you must do more than just eat less; you need to clear the Phlegm-Fluid and restore the function of the Spleen. The goal is to 'flip the metabolic switch' back on, creating a body that can naturally burn energy and maintain its own balance.