Swelling can affect body weight, and swelling can lead to a condition of weight gain. In clinical practice, swelling can be divided into physiological swelling and pathological swelling. Physiological swelling, such as drinking too much water before going to bed, causes water to be discharged from the body in a timely manner, resulting in swelling, and the increase in water will lead to weight gain. Pathological swelling common causes, such as kidney disease, liver disease, heart disease, etc. will lead to swelling. Take kidney disease as an example, when kidney disease occurs, the glomerular filtration rate decreases, resulting in water and sodium retention in the body that cannot be excreted through urine, and weight gain occurs in the body due to water and sodium retention. Therefore, for patients with swelling, weight loss will occur after the swelling is reduced.