Governments must assess the evidence and give a clear message to consumers and industry as to what is important or unimportant and hence what changes in food consumption and production are to be encouraged. By this means, confusion - for example, as to whether imported food is better for the climate than home-produced food (i.e. the food miles debate) - can be clarified. Short-lived social marketing campaigns may be doomed to fail. Substantially more research is needed on the causal links between campaigns and long-term patterns of behaviour and consumption.