Sudden weight gain is more common in this endocrine disorder, and many endocrine disorders can lead to weight gain. The first one is hypothyroidism, which may result in systemic fluid accumulation and weight gain. The second one is Cushing’s syndrome. Cushing’s syndrome has its own characteristic features, such as smaller limbs, larger stomach, rounder face, thicker fat on the back, and the possibility of purple lines on the skin under the stomach. So, you can look at your stomach and see if there are any of those more obvious purple lines. If there are, cortisolism is highly suspected. It is recommended to go to the endocrinology department of the hospital to improve the relevant tests to see which aspect of the disease is responsible for this weight gain. Of course, there may also be digestive system diseases such as liver cirrhosis ascites, so you should seek medical attention in a timely manner.