Dr Deborah Cohen, investigations editor at the British Medical Journal, examines a new generation of diabetes drugs that some drug companies hope could also be a magic treatment for obesity. Millions of prescriptions of it are given out every year, but are they also associated with an increased risk of cancer? The drug companies hope to expand, but lawyers in America are bringing legal action on behalf of some people who claim that their health has suffered. Some scientists say they've found new evidence that suggests there are cases where the risks might outweigh the benefits. Dispatches explores the argument that drug companies should be made to share all their research with the public.