Generic public health messages, such as 'eat 5 fruit and vegetables a day', are more effective at shifting dietary habits than very specific advice and guidance tailored according to individual needs, say researchers.
In the new study from health economists, published in the journal European Economic Review, researchers tested the impact of different public health information on dietary choices across a sample of 300 people from low income backgrounds.
In their experiment, which allocated a budget to individuals and asked them to select items in a shopping basket, participants either received very specific information individualised to them, received generic health information, or received no information at all.
For those provided tailored information, they were given easy-to-understand information about their risks of developing diabetes or heart disease, as well as easy-to-follow dietary and health recommendations to minimise risks.
The team from the universities of Bath and Edinburgh, with international colleagues at the University of Malta, found that participants who received generic health information selected food baskets that, on average, contained less total fat and less saturated fat (approximately 20% less) relative to the no information group, and spent 34% less on unhealthy items. For those receiving tailored information, they found no difference in the number of unhealthy items chosen, nor in the nutritional content of the basket compared to the no information group.
The authors say this is because the majority of those who received tailored information actually got better news about their own health than they might have otherwise imagined. This meant individualised information did not have an effect in the sense that participants were given a 'free pass' to continue with their current (unhealthy) dietary choices.
In the context of efforts to tackle obesity, including through the UK's government's latest obesity strategy in response to COVID-19, the researchers say this work should act as a warning about increasing trends towards individualising health information. They suggest their results may explain why efforts to offer personalised health information by public health agencies have had limited success so far, including the NHS's Health Check programme.
Dr Jonathan James from the Department of Economics at the University of Bath explains: "Over recent years and in an effort to nudge us towards healthier behaviours there has been increased reliance on tailoring health information to make it very specific to individuals. This is premised on a theory that by individualising advice and guidance it will have more resonance with individuals and be harder to ignore.
"Yet, as our study shows, tailoring health information in this way is not a silver bullet in tackling obesity; it can actually be less effective at shifting behaviours than generic health information which is relevant to all. As we observed, this can be because the tailored information provided actually gives a better assessment of someone's health than they may have imagined and therefore inadvertently gives them a free pass to continue to eat unhealthily."
Co-author Dr Jonathan Spiteri from the University of Malta added: "Policymakers designing responses to obesity need to bear these results in mind when considering future health interventions. Often keeping it general when it comes to public health messages will also make it most effective."
These findings on the impact of generic information are in line with recent evidence on the effectiveness of information made available at the time of purchase, such as calorie and health information on product labels.