MetroRishi, four, loses 2st with op: Sweet-toothed youngster has extreme ...MetroA boy of four, believed to be the youngest person in the world to have weight-loss surgery, has lost 13kg (2st) six months after his operation. Rishi Khatau had ballooned to 44kg (7st) and was wearing large adult T-shirts and 92cm (36in) waist trousers ...