There are many reasons that lead to eating less and having a big stomach, and the common clinical reasons are sedentary, liver disease, indigestion and so on. 1. Sitting for a long time: people who sit for years and years, because there is no exercise, so generally eat less. But even if you eat less, your stomach will be relatively big because of the fat that tends to accumulate in the abdomen due to sedentary behavior. 2. Liver diseases: such as cirrhosis ascites, fatty liver and other liver diseases, because of liver disease, so the patient will be due to abnormal bile secretion and affect the digestive ability, which in turn causes loss of appetite. However, there is fluid accumulation in the abdominal cavity or increased volume of the liver, so the stomach is large. 3. Indigestion: Due to the decreased ability to empty the food in the gastrointestinal tract in time, which leads to the accumulation of food in the gastrointestinal tract for a long period of time, these foods produce a lot of gases in the process of fermentation, which can cause abdominal distension. So the phenomenon of eating less and having a big stomach will occur. People who eat less and have a big stomach may have other diseases that cause it. If it is accompanied by other uncomfortable symptoms, you should go to the regular hospital to find out the cause of the disease and follow the professional doctor’s advice to choose the right treatment for you.