My boyfriend is a good counterexample. He is very fat, so no matter how much he eats, his stomach will not change.
In fact, eating habits are more important than exercise. First, choose digested food, and don't add rice cakes, glutinous rice and other difficult-to-process foods to the menu. In addition, be sure to remember to chew fully. As the first digestive system, if food is not fully chewed and digested, it will definitely increase the burden on the stomach through the esophagus. A doctor and aunt once told me that 24 times in the mouth can be considered as full chewing, and less is the trouble of the stomach!
Let's talk about sports. Actually, it's no use just practicing your abdomen. The more abdominal fat there is, the higher the demand for abdominal muscle training is, and the fat is particularly easy to rebound after it is molded into muscle. Simply put, you must cooperate with fat reduction. For example, after practicing vest line carving (keep it) and running for half an hour, you will find that your stomach will be more stylish after brushing fat.