Why does malnutrition cause pot belly or cause like a pot belly in the stomach area?

They dont get enough protein in their diet so their capillary colloidal osmotic pressure goes down. This allows water to leak into the interstitium causing edema. Ascites (the name for pot belly in malnutrition) is when this fluid leaks into the peritoneal cavity (the space between the lining of the abdomen and abdominal organs) giving the appearance of a pot belly.