A middle aged woman with morbid obesity – how to treat?

Case scenario

Shirley is 41 years of age and has presented in despair about her huge weight gain since the birth of her sixth child, who is now 10 years old. She is 165 cm tall and weighs 179 kg. She is dyspnoeic on even minimal exertion, has painful knees and has recently developed a large inguinal hernia. She reports that she is uncomfortable in bed at night and sleeps poorly.