Q. I've heard that taking herbal diet medicine can cause irregular periods or changes in menstrual flow. Why does this affect weight loss?

Many people attempt extreme fasting out of a strong desire for quick results, but this often leads to dizziness and overall exhaustion. The human body possesses a strong survival instinct; when energy is depleted, it prioritizes essential functions and suppresses reproductive functions, signaling that it is not an ideal time for pregnancy. Medically, a sudden drop in body fat or nutrient deficiency causes fluctuations in hormones like leptin, which affects the hypothalamus in the brain. This destabilizes the secretion of female hormones, leading to irregular periods or abnormal uterine bleeding. In TKM, this state is referred to as Blood Deficiency (血虛) and Qi Deficiency (氣虛), meaning the body's vital energy and blood levels are depleted. If this is compounded by Blood Stasis (瘀血, stagnant blood) or Phlegm-Fluid (痰飮, metabolic waste), the circulation of Qi and Blood is blocked, hindering blood flow to the uterus. The real issue is the subsequent ripple effect: an irregular menstrual cycle often leads to severe edema (swelling) and makes appetite control more difficult due to hormonal instability. Consequently, the effort to lose weight results in a 'boomerang effect' of decreased metabolism. Therefore, rather than simply restricting calories, I recommend a balanced approach that replenishes deficient Qi and Blood while eliminating metabolic waste. Establishing internal balance is the foundation for healthy weight loss without the yo-yo effect. If your menstrual cycle has changed, please avoid extreme fasting and first assess your body's overall condition.