The old flatulence, i.e. bloating, during weight loss may be caused by mental factors, intestinal flora imbalance, gastritis, peptic ulcer and other reasons. 1. Mental factors: too much psychological tension, anxiety, stress during weight loss induced autonomic nervous system dysfunction, inhibit gastrointestinal peristalsis affecting the digestion of food, resulting in the stomach is always bloating. 2. Intestinal flora imbalance: eating an unbalanced diet or taking drugs and other reasons, resulting in intestinal flora imbalance, intestinal harmful bacteria increase, fecal matter stays in the intestinal tract, fermentation, gas production increases, resulting in the stomach always flatulence. 3. Gastritis: chronic inflammation and erosion of gastric mucosa, weakened digestive ability, affecting the digestion of food, causing flatulence, nausea, acid reflux and other symptoms. 4. Peptic ulcer: Due to the damage of gastric mucosa, the digestive ability decreases, resulting in symptoms such as flatulence, acid reflux, heartburn and stomach pain. If the symptoms continue to be unrelieved, it is recommended to consult a doctor in a timely manner to identify the cause of the disease and follow the doctor’s instructions for treatment.