The main symptoms of food retention in adults are bad breath, abdominal pain, constipation, etc., which may also be accompanied by acid reflux and belching (burping). 1. Bad breath: due to eating too much, food stays in the stomach for too long, food fermentation and gas production increase, which can easily lead to bad breath. 2. Abdominal pain: A large amount of food accumulates in the stomach and prolongs the gastric emptying time, which easily leads to smooth muscle spasm in the gastrointestinal tract and abdominal pain. 3. Constipation: Due to the reduced absorption function of the gastrointestinal tract, gastrointestinal peristalsis is weakened, and further accumulation of food, the aggravation of symptoms can lead to the accumulation of feces, prolonged defecation time, and the formation of constipation. 4. Acid reflux, belching (hiccups): due to the prolonged residence time of food in the stomach, stimulating the secretion of gastric acid, prone to acid reflux, belching (hiccups) and other symptoms, but also lead to increased abdominal pain.