The causes of increased fat in the lumbar L5s1 spinal canal may be inflammation, hormonal drug stimulation, and intravertebral lipoma. 1. Inflammation: when the lumbar spine L5s1 has inflammatory injury due to various reasons, due to the stimulation of inflammatory mediators and secretions, it can cause the over-activity of the fat in the spinal canal and increase the fat. 2. Hormonal drug stimulation: when patients take hormonal drugs for a long time, it can redistribute the fat in the body, leading to abnormal proliferation of fat in the spinal canal, which increases the fat in the lumbar L5s1 spinal canal. 3. Intravertebral lipoma: Intravertebral lipoma is a kind of congenital tumor, which belongs to benign tumors, and the cause of the disease is often congenital malformations, such as spina bifida, spinal bulge, etc., which makes the fat in the lumbar spine L5s1 vertebral canal increase abnormally. There may be other reasons for the increase of fat in the lumbar L5s1 spinal canal, so it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment under the guidance of the doctor.