Q. I'm experiencing heart palpitations and insomnia after taking diet herbal medicine. Why exactly is this happening?

To understand these reactions, it is important to look at the principle of 'energy expenditure.' Your body possesses a natural tendency to both conserve and burn energy; diet herbal medicine specifically stimulates the mechanisms that burn energy. In modern medical terms, this is achieved by activating the sympathetic nervous system to raise the basal metabolic rate. However, the sensitivity of this 'switch' varies by individual, which is why some patients feel an increase in vitality while others experience intense palpitations. From a Traditional Korean Medicine (TKM) perspective, these differences are often related to one's constitution or the state of their 'Qi.' For instance, those with Spleen Deficiency (脾虛, bi-heo)—where digestive and absorptive functions are weakened—may find it difficult for their body to handle potent medicinal herbs, leading to increased anxiety or palpitations. Similarly, patients with significant Blood Stasis (瘀血, eo-hyeol) or Phlegm-Fluid Retention (痰飮, dam-eum) may experience instability in their condition because metabolic byproducts are not cleared from the body efficiently. Ultimately, the key is whether your body can tolerate the current speed of metabolic acceleration. Enduring these symptoms is not the answer. If the discomfort persists, the herbal formulation or dosage must be finely adjusted to suit your specific constitution. Finding the optimal balance that your body can sustain is the true key to achieving sustainable weight loss without the yo-yo effect.