The challenge was difficult enough when infectious diseases were the leading driver of the burden of ill health 100 years ago. Today, when chronic diseases, with their strong links to lifestyles, are the main cause, it is more difficult still. It has always been easier for governments to build infrastructures than change human behaviour. But the clean water pipes and sewers that got rid of infectious diseases have long been in place; now we need to tackle lifestyles. Take obesity, which reduces life expectancy by nine years on average, and increases the risk of a wide range of ailments (heart disease, diabetes and several cancers among many). The causes of obesity are well known: too little exercise and too much fat, sugar and salt in the diet. The Tories set targets in 1992 aimed at reducing the health hazard to 6% for men and 8% for women by 2010. In the succeeding decade, obesity in men rose by two-thirds to 22% while the female rate (23%), rose almost as fast. Yesterday, the man charged by the Treasury with finding a way of resolving this challenge, reported on how it can be tackled.

This is the second major report on health that Derek Wanless has delivered in two years. His last, in April 2002, transformed spending on health with a devastating documentation of the shortfall in UK investment - a cumulative underspend of £230bn over 25 years - compared with the European average. Yesterday he had a more difficult picture to analyse. Yet it cleared away several barriers. First was its readiness to tell ministers that they should be more ready to intervene, even though it acknowledged that many more players would need to be involved. A second hurdle - Tory "nanny state" taunts that have inhibited Labour moves - was neatly undermined by the savings, which Wanless showed can be achieved. The diseases that obesity triggers cost the NHS £470m in 1998. Surely a party which wants to cut public expenditure, should be taking such savings more seriously?

This may be difficult, but preventive health programmes around the world have changed behaviour. The UK can point to success with car seat belts and crash helmets for motorcycle riders. Finland cut heart disease by a programme that included diet and exercise. Australia reduced high skin cancer rates by high-profile sports people leading the way with the use of sun creams, hats and T-shirts. And more recently California - followed by New York and Dublin - has introduced no smoking bans in the work place and public places, including bars. Wanless was rightly scornful of Labour's timid targets on smoking. After a dramatic drop over two decades - down from 45% of people to 27% - smoking has flattened out. Currently ministers are only aiming at 24% by 2010, when in California it is already down to 17%.

Reformers looking for tightly prescribed programmes will be disappointed. The report is concerned with the framework, under which such programmes should operate. There are plenty of people to draw up the prescriptions, as the Consumers' Association demonstrated yesterday with its 12 key steps for achieving a better national diet. But Wanless should have set out incentives to make Whitehall conform.

The biggest advance yesterday was the destination of the report. It goes direct to three key departments - health, Treasury, Downing Street. It analysed what went wrong with earlier reviews: an absence of coherent objectives and a failure to draw up action plans. Its message to the health secretary was unambiguous: make the reduction of obesity and smoking as important as waiting list reduction targets. For far too long governments have focused on improving our sickness service, and far too little on promoting our health. Wanless has opened the way to a change of course.