2 The condition, current treatments and procedure
2.1 Overweight is defined as a body mass index (BMI) of 25 kg/m2 to 29.9 kg/m2 and obesity as a BMI of 30 kg/m2 or more. Overweight and obesity increase people's risk of type 2 diabetes, coronary heart disease and hypertension. Weight loss reduces these risks and improves life expectancy.
2.2 Obesity is managed by dietary advice, physical activity and exercise, lifestyle and behavioural changes, and medication. Bariatric surgery is considered for people:
whose BMI is over 40 kg/m2, or over 35 kg/m2 if they have other significant comorbidities, and
who have not been able to reach or maintain a clinically beneficial weight using non‑surgical measures.
Surgical procedures include gastric banding, sleeve gastrectomy, or Roux‑en‑Y gastric bypass or other diversion procedures.
2.5 The procedure is usually done in an outpatient setting without endoscopy or sedation. The patient swallows a capsule containing the deflated balloon, which is attached to a fine delivery catheter, with water. If they have difficulty swallowing the capsule, a stylet can be fed through the catheter to stiffen it. This allows the doctor to help push the catheter during swallowing. After the capsule reaches the stomach this stylet is removed. The position in the stomach is confirmed by X‑ray using guide marks on the catheter. The capsule disintegrates and the balloon is inflated with a fixed amount of fluid (for example, distilled water and citric acid) through the connected catheter. After the balloon is inflated, the catheter is detached by pulling it firmly from the patient's mouth. Imaging is done to recheck position and inflation. After a short wait to make sure the patient can tolerate the balloon, they are discharged with medication including anti-emetics, antispasmodics and proton pump inhibitors. About 4 months later, a resorbable material element of the balloon degrades, which then allows a release valve to open and expel the fluid into the stomach gradually. The deflated balloon then passes through the gastrointestinal tract to be excreted through the bowel.