From a Western perspective, artificial sweeteners like aspartame and sucralose provide sweetness without calories, confusing the brain's reward pathways. The brain expects energy but blood sugar doesn't rise, increasing cravings for high-calorie foods. Caffeine stimulates the sympathetic nervous system, raising cortisol and causing blood sugar fluctuations that boost insulin resistance, reducing fat-burning enzyme activity and stubbornly retaining abdominal fat. In Traditional Korean Medicine, these cold-natured, additive-laden drinks induce Spleen Deficiency (Pixu). The Spleen governs digestion, absorption, and water metabolism; when impaired, undigested fluids and impurities form Phlegm-Fluid (Dam-eum), leading to a heavy body, sluggish metabolism, and difficulty losing weight even with reduced intake. Caffeine temporarily boosts Qi and Blood but ultimately causes Qi Stagnation (Kiche), predisposing to Blood Stasis (Eohyeol). Thus, warm teas or plain water are recommended over such drinks, though individual constitution and health status should be considered for personalized advice.