The immediate side effect of overeating is indigestion can vary in intensity. Gaining weight is another concern. Other major side effects include nausea and drowsiness after heavy meals. Heavy meals can also cause pain in gallbladder. Overeating can also hamper one’s reflexes.
Eating more means that the stomach has to work harder to digest and process food. This causes increased amounts of blood to rush to the digestive system in order to cope with the overload. This inhibits blood and nutrients from reaching other parts of the body. This is a real threat to people with cardiovascular illnesses, and it can result in cardiovascular arrest and high blood pressure.