The Change4Life initiative to combat child obesity is the latest in a long history of public strategies and, says Niall Dickson, success will rely on it grabbing public imagination

The government has produced yet another initiative to improve public health. Change4Life aims to combat rising obesity rates among children. But let history be our lesson. This is an area where high expectations have seldom been realised.

In spite of notable local successes and the real achievement around smoking in public places, it is hard to demonstrate significant national impact from a succession of well intentioned initiatives, from health action zones in the 1990s to more recent white papers and strategies.

As we embark on yet another admirable attempt, it is worth asking why this has proved such an intractable issue. For a start, there is no consensus about what can realistically be achieved. The 2010 public service agreement targets at least set a defined goal - but we know they will not be realised.

The language of equality assumes that, as with income inequality, it is the gap between the haves and the have-nots that matters. But no one is arguing for a curb on the "excess" health of the better off. The gap in this instance is important only in that it highlights injustice and the potential for improving the health status of lower socioeconomic groups.

Yet there is debate as to whether programmes should be largely confined to those on low incomes, to narrow the gap, or whether to raise the health of everyone. There is also underlying disagreement about the role of "social determinants", with much of the public health world lined up behind the concept. Others, like outgoing NHS London director of strategy and commissioning Paul Corrigan, protest this approach can convert association into rigid causality.

Though external pressures and lack of opportunities can make it harder for disadvantaged people to live healthily, the obvious fact that hundreds of thousands of people on low incomes lead relatively healthy lives demonstrates individuals can play a part in their own destiny.

To that extent the government is right in its twin track approach - acknowledging wider factors the state can influence while accepting that personal responsibility and helping individuals to change their behaviour are also vital.

So what is to be done?

The difficulty has been in finding interventions that can deliver that individual behaviour change. Partly this is down to the lead time and the difficulty of isolating factors that can be shown to make a difference, as well as uncertainty about how to engage with communities.

First, it would help if at local level we could define what the NHS can and should do on its own, what it should do in partnership and what it should leave for others to do, albeit with encouragement. The criteria in each case should be pragmatic rather than dogmatic.

Second, the great strength of our healthcare system is its universal coverage. It has struggled to look at the population it serves with the eye of an insurer who knows it is in its own interest to reduce future risks - in this case by encouraging some behaviours and discouraging others.

The good commissioner should feel able to invest in the longer term where there is a reasonable expectation that it will pay off in improved health and saved lives.

As the King's Fund's recent report Kicking Bad Habits shows, making better use of social marketing techniques and data analysis tools to communicate messages and motivate individuals has real potential. We are getting better at understanding which interventions are most likely to work.

Yet there is no need to be apologetic about interventions that can deliver quick wins. We could push harder for the take-up of blood pressure checks, statins and simple prophylactics such as aspirin, which can save lives and which have the greatest potential among socially disadvantaged groups.

Likewise we know that around 60 per cent of health inequalities can be attributed to higher rates of smoking. By concentrating prevention resources on this, significant advances can be made.

Most of the public do not have a clue what primary care trusts do. But as some PCTs have shown, it is possible to engage and inform. In particular, as Change4Life shows, there is enormous scope to do more with children and young people.

Finally, if we want to gain public support, instead of talking about inequalities, why not focus local and national campaigns on the idea of saving lives? The 100,000 Lives campaign in the US fired imagination in the acute sector. Why not calculate the number of lives that could be saved, for example, by improving the health status of specific groups on low incomes through reduced smoking?

If the healthcare system could capture public imagination, public health could recapture its place at the centre of the NHS.