After eating, the stomach will expand and its volume will expand several times. Abdominal pressure will increase, and you need to bend over more when washing your hair, which will also increase abdominal pressure and affect gastrointestinal peristalsis and digestive function.

Therefore, it is not recommended to wash your hair or shave your hair after meals. You can wash your hair two hours after a meal, but if you eat less when you eat, it will generally not affect your normal shampoo.