Last month, Shashank Gangil walked through a Hong Kong hospital corridor proudly carrying a newborn in each arm. The 39-year-old real estate professional had just become a father of twins, an event that would have seemed unlikely just 18 months earlier. In late 2024, Gangil weighed 94kg (207 pounds) and faced a worrying list of health issues: high cholesterol, signs of fatty liver disease, nagging plantar fasciitis and poor sleep. For years, he had told himself that “this is genetics”, but that...