The government's "nudge" approach to public health may struggle to make much impression on improving population health, warn experts on

An accompanying editorial argues that the notion of nudging adds nothing to existing approaches and risks wasting resources.

Theresa Marteau, Director of the Behaviour and Health Research Unit at Cambridge University (the Department of Health Policy Research Unit on Behaviour and Health), and colleagues ask whether the concept stands up to scientific scrutiny as a basis for improving population health.

Nudging involves altering environments to prompt healthier behaviour, without banning particular choices or using financial incentives.

The concept of nudging people towards healthier behaviour has captured the imagination of the public, researchers, and policy makers, say the authors. Its appeal lies in the seemingly simple, low cost solutions that can be applied to a wide array of problems, and there is some evidence that it can work.

For example, putting yellow duct tape across the width of supermarket trolleys with a sign requesting shoppers to place fruit and vegetables in front of the line doubled fruit and vegetable purchasing, and placing fruit by the cash register increased the amount of fruit bought by school children at lunchtime by 70%.

However, they argue that, "at present, the evidence to support the view that nudging alone can improve population health is weak." They also point out that nudging has the potential to generate harms as well as benefits, particularly if an emphasis on nudging results in a neglect of other, potentially more effective interventions.

Nudging is often used very effectively by industry to prompt unhealthy behaviour, for example in the marketing of food and alcohol.

The authors argue that effective nudging "may require legislation, either to implement healthy nudges … or to prevent unhealthy nudges from industry."

The authors argue that research is needed to determine the effectiveness and cost effectiveness of nudging and related ideas. Currently there is precious little good science on which to build practical examples which would work.

They conclude: "Without regulation to limit the potent effects of unhealthy nudges in existing environments shaped largely by industry, nudging towards healthier behaviour may struggle to make much impression on the scale and distribution of behaviour change needed to improve population health to the level required to reduce the burden of chronic disease in the UK and beyond."

In an editorial, Chris Bonell and colleagues at the London School of Hygiene and Tropical Medicine also question whether it is clear what is meant by nudging and whether it really offers anything new, and warn that "little progress will be made if public health policy is made largely on the basis of ideology and ill defined notions that fail to deal with the range of barriers to healthy living."

A blog by BMJ News Editor, Annabel Ferriman, argues that the Conservatives have invented the nudge as a new way of encouraging people to live in a healthy way, and asks: can you tell your nudge from your nanny?