It is a common frustration to feel like you gain weight while others eat freely. This isn't a matter of willpower; it's a physiological imbalance. From a Western medical perspective, when the metabolic system is disrupted, insulin drives the body to store excess energy as fat cells rather than burning them for fuel. In Traditional Korean Medicine, we call this state Spleen Deficiency (Biheo). The Spleen is responsible for the 'Transformation and Transportation' of nutrients. When this 'engine' is weak, it cannot burn fuel efficiently, leaving behind metabolic waste called Phlegm-Fluid (Dameum). These sticky substances block the circulation of Qi and Blood, causing the metabolism to stagnate. Furthermore, if stress or poor circulation persists, it can lead to Blood Stasis (Eo-hyeol), further clogging the body's pathways. The fundamental solution isn't just eating less; it is about tonifying the Spleen to restore its 'combustion' function and clearing out the accumulated waste that traps energy as fat.