The growth of diet-related disease: when, and how, should governments intervene?

The increase in diet-related disease is a particualrly topical issue; governments are becoming more concerned about rising obesity, poor nutrition, and the negative health outcomes that arise from these. In 2006 24% of adults (aged 16 or over) in England were classified as obese according to figures from the Department of Health- a significant increase from the 15% of adults classified as obese in 1993. So should the government intervene to reduce obesity? And what policies are likely to be effective?