Placing a water balloon inside the stomach to suppress the appetite is being touted as a way for obese people to lose about 16kg in six months. The treatment, known as intragastric balloon, was the least invasive procedure to reduce weight so far, said Wilfred Mui Lik-man, honorary clinical assistant professor of the department of surgery at Chinese University. Doctors put a deflated balloon inside the stomach by using an endoscope and fill it with saline. It takes about 30 minutes and leaves patients feeling full even after eating a small amount of food. It is seen as an alternative to common surgical procedures such as a gastric belt, which is strapped around the stomach like a belt, and intestinal bypass operations to reduce food intake. Dr Mui said the treatment was suited to obese people whose medical condition means they must lose weight but cannot undergo surgery. The balloon method began to grow popular in Europe about five years ago, and last November the university became the first institute in Asia to offer the procedure. Since then, 48 patients have received it, losing on average 16kg - about 15 per cent of their original weight. 'The purpose of the treatment is to change the eating habits of patients. It is very common for people to gobble their food down within a short period of time,' Dr Mui explained. 'So people will easily overeat before the message of fullness has been sent to their brain. This eating habit can easily give rise to the problem of obesity.' Patients may suffer minor side effects such as nausea and vomiting in the first two weeks but these gradually disappear. The balloon must be removed after six months. During that time patients are trained to reduce their appetites and eat slowly. University colleague Enders Ng Kwok-wai said overseas experience showed that nearly 90 per cent of patients could maintain their lower weight for at least two years after the procedure. Dr Ng said that the treatment should only be used on people who are identified as obese, with a body mass index over 30. It should not be used on patients who had received gastric surgery or suffered from gastrointestinal diseases, such as ulcers. Women who are pregnant or breast-feeding or those with psychiatric illnesses are also not recommended to receive the treatment.