Visitors to a medical fair at the weekend will be able to watch two anti-obesity operations and two heart operations broadcast live from Union Hospital. A surgeon will place a balloon in the stomach of a 79kg woman, while a 100kg man will have his stomach stapled to reduce its size. The hospital's medical director, Anthony Lee Kai-yiu, said the operations were minimally invasive and would not cause much bleeding, so members of the public would not find the footage too disturbing. But people will be warned that some scenes might be unsettling. Consultant surgeon Wilfred Mui Lik-man will perform the anti-obesity operations. The balloon procedure on Chan On-ki, 45, is expected to take 30 minutes. It will be Ms Chan's second such operation and she has already shed 10kg. The balloon has to be taken out after six months. The staple operation on Alex Tsiang, 52, will take about an hour. Mr Tsiang has had the balloon operation and is now hoping to lose more weight with the stapling. Dr Mui said stomach stapling was appropriate for someone with a body mass index (BMI) of 30 or more, while the balloon was better for people with a BMI of 25 or more. He said the services were carried out to improve the patients' health, not for cosmetic reasons. The two heart operations, each lasting one to two hours, will be performed by cardiologist Steve Li Siu-lung. The Hong Kong International Medical and Health Care Fair is being held at the Convention and Exhibition Centre in Wan Chai.