After losing weight, the body does not menstruate, mainly because in the process of losing weight, the body's nutrition is reduced, and the nutrition absorbed by the brain is also reduced, which will inhibit the release of luteinizing hormone from the hypothalamus-pituitary-ovary axis, the follicle will not develop, and menstruation will stop. In addition, it will also lead to endocrine disorders during weight loss, causing irregular menstruation.