Diet herbal medicine performs four key roles: ① appetite suppression (Mahwang-based formulas reduce hunger), ② basal metabolism boost (fat-burning by warming herbs), ③ water/waste elimination (improves bloating and edema), ④ rebound prevention (constitution improvement maintains weight). Constitution-based prescriptions ensure safety and effectiveness. Typical 1–3 month course, with most losing 5–10kg in 3 months while maintaining muscle mass.