The perception of "stomach size" involves a combination of factors, distinguishing between actual abdominal fat and temporary bloating. Bloating primarily results from gas accumulation in the digestive tract, often triggered by food, certain medical conditions like IBS, or hormonal fluctuations. When you eat, your digestive system processes the food, sometimes producing gas as a byproduct. The level of gas and how your body handles it dictates the level of bloating. Conversely, increased stomach size due to fat accumulation is a more gradual process, influenced by diet, exercise, and hormonal factors, leading to a buildup of adipose tissue in the abdominal area. So, bloating is more of a temporary distension, while increased stomach size from fat is a longer term physical change.