Dieters desperate to get rid of that spare tyre can finally let it all hang out. That muffin-top could actually help to regulate the immune system and provide a first line of defence against infection and viruses. A hard-to-shift beer belly could even help regenerate damaged tissue after an injury. The fatty membrane in the belly, called the omentum, has never seemed to serve much of a purpose. But now the research by scientists in Chicago has shown it can be a health benefit - and their discovery could lead to the development of new drugs for organ transplant patients...