Possible reasons for coughing up phlegm and increasing the amount of phlegm after meals include respiratory system diseases, digestive system diseases, circulatory system diseases and so on. 1. Respiratory diseases: such as various upper respiratory tract infections, lower respiratory tract infections, etc., may stimulate coughing after eating, coughing process is conducive to the expulsion of phlegm, thus coughing up sputum after meals and sputum volume increases. 2. Digestive system diseases: such as gastroesophageal reflux disease, pancreatic sphincter relaxation, etc., after eating, there will be food reflux through the esophagus to the pharynx, and when mistakenly inhaled into the trachea, it will stimulate the airway to secrete mucus, inflammatory reaction, and then increase the amount of phlegm. 3. Circulatory diseases: If the patient has left heart failure and other heart diseases, after eating, due to the accelerated blood circulation, the heart does more work, which may aggravate the left heart failure, and then there is an increase in the amount of sputum, which is often manifested as pink foamy sputum. If you cough up sputum after meals and the amount of sputum increases, you must consult a doctor in time to find out the cause and then treat the cause, so as not to delay the condition.