Coca-Cola recently announced that it would feature the calorie count of its drinks more prominently on cans. Its strategy is designed to head off increasingly serious moves from governments and regulators to reduce people's intake of sugary drinks, most notably from Michael Bloomberg, the Mayor of New York, who recently tried but failed to ban very large bottles of pop.
The problem with junk food is not only that the products are hard to resist, says Dr Paul Connell, Senior Lecturer in Marketing at Cass, but also that the appeal of the brands can be so powerful that some people develop a parasocial relationship with them: they treat them like friends, forgiving transgressions and defending them against negative stories. People quite literally love their junk food.

In a paper* co-written by Lauren F Mayor, of the Zicklin School of Business at Baruch College, City University of New York, Dr Connell says that conventional campaigns have highlighted the benefits of healthy eating, but junk food brands produce "resilient preferences" that are resistant to information about healthy alternatives. Muesli just can't compete head-to-head with branded sugared cereals that make people feel pleasure and comfort. So, Dr Connell wondered, is there another way?

Think healthy
Dr Connell and Mayor carried out two studies in which people reported the positive emotion they felt towards 7 Up and Kellogg's Frosted Flakes (Frosties in the UK). A group of the participants was "primed for health", that is, unconsciously made to think about healthy food. This involved doing a word-search that contained 13 words, six of them neutral (such as green, lamp, plant) and seven related to health (nutritious, strong, thin, and so on). Afterwards, these participants reported their attitudes towards the branded, so-called unhealthy foods. The outcome was that, once primed for health, people who had previously expressed positive emotion towards the unhealthy foods found them less appealing.
This has important implications. "We suggest that it is possible that one way to prod people into making better decisions is not to increase the attractiveness of healthy options, but decrease the attractiveness of unhealthy ones," wrote Dr Connell and Mayor. "Our results indicate that activating a health goal in a subtle manner has the potential to strip junk foods of their fun and sensory pleasure."
Dr Connell and Mayor's studies are part of a growing body of research that is looking at whether preferences can be changed through priming, prompting or exploiting unconscious biases.

Children's TV
The UK Government's Behavioural Insights Team is looking at exactly this. It is often called the nudge unit, after the book Nudge: Improving Decisions About Health, Wealth and Happiness by Richard Thaler and Cass R Sunstein, which argues that encouragement is more effective at changing behaviour than legislation.
Governments in other countries are already doing it. In a Mexican scheme parts of shopping trolleys were marked out for fruit and vegetables.
Shoppers bought more - and the retailer saw no decrease in profits. In Iceland the Government teamed up with the children's TV show LazyTown to promote fruit and vegetables. Sales increased 22 per cent and Iceland is now one of the few countries where childhood obesity is falling.
The idea of nudging people into healthy eating certainly has legs, says Rory Sutherland, a behavioural expert and Vice-Chairman of Ogilvy & Mather, the advertising agency. He thinks that governments should promote diets that exclude certain foods on certain days because, he says, they are easier to follow than "cognitively demanding" calorie-counting diets.
"Religions show a good understanding of human psychology in this respect," he says.
"When Moses went into the desert he didn't live off 1,700 calories and limit himself to 21 units of wine. He fasted."
Sutherland adds that something as simple as changing the order of foods on menus can change choices. Advertisers are well aware of this, but governments are catching up.

Bizarre result
Does nudging hold the key to fighting obesity? Maybe, but it's not that straightforward. Behavioural studies are notoriously hard to replicate in real life.
Plus, the mind is unpredictable. A second, bizarre result of Dr Connell and Mayor's studies was that, when primed with healthy eating messages, people who felt negative emotion toward the food brands actually became more attracted to them. Food preferences are complex, and are tangled up with extraneous influences such as social norms, class and self-image.
Nudging can work, but it is an inexact science.
If policymakers take the behavioural route, they must be prepared for unforeseen consequences, odd results and failures.

*Activating Health Goals Reduces (Increases) Hedonic Evaluation of Food Brands for People Who Harbor Highly Positive (Negative) Affect Toward Them, by Paul M Connell and Lauren F Mayor

Jeremy Hazlehurst is a freelance writer. He can be contacted at jeremy.hazlehurst@gmail.com