This Sunday:

• Remember that guy who was swallowed up by a sinkhole in Florida last month? Sinkholes don't just happen in Florida, the earth has also opened up in Guangzhou, Guatemala City and other places where the ground isn't quite as stable as it looks. Jon Henley tells us how they form, and where they're likely to be found.
• Anirban Mukhopadhyay tells us why cutting down on what you eat is a far more effective way to lose weight than burning calories through exercise.
• In Short Science: Russian scientists find a new type of bacteria in a subglacial lake; polar bears are out of luck as Canada rules it's OK to continue exporting their skins, teeth and paws; and we learn it's a bit early to say, but it's probably best to pass on extra salt as a high-sodium diet may be a risk factor for developing autoimmune diseases.