Menstruation is not a simple matter of blood coming out of the uterus, it is a functional expression of endocrine function of human body, which involves the harmonization of neuroendocrine function of “thalamus-pituitary gland-ovary-uterus”. It involves the harmonization of the neuroendocrine functions of “thalamus-pituitary-ovary-uterus”. The main link affected by weight loss is the thalamus-pituitary gland, which in turn affects ovulation of the ovaries. 1. Inadequate protein intake: Laxatives and dieting firstly cause a lack of protein in the body. The pituitary gland secretes a large amount of gonadotropin, which prompts the follicles in the ovaries to mature, ovulation occurs and menstruation is produced. This gonadotropin is a sugar-containing protein, long-term nutritional deficiency, lack of protein, the pituitary gonadotropin secretion is insufficient, the result is that the ovaries in the follicles do not mature, and over time the ovarian function is reduced, and even atrophy premature failure. 2, metabolic disorders: irregular bowel movements and eating habits themselves disrupt the balance of intake and consumption functions in the body, causing endocrine disorders in the body, affecting the metabolic balance of sex hormones and leading to menstrual disorders and even amenorrhea. 3, inhibit the function of the thalamus: some diet pills are achieved by inhibiting the function of the hypothalamus, i.e., no hunger, no desire to eat. The “thalamus-pituitary-ovary-uterus” axis will be short-circuited when the appetite is suppressed and the hypothalamus gonadal release is also suppressed. In addition, the psychological stress of the dieter can also trigger the dysfunction of the hypothalamus, thus affecting the normal menstrual flow. In short, blind weight loss is not advisable for women, especially young women who have not had children. The last sentiment of patients who have amenorrhea due to weight loss in clinical practice is regret.