Junk food is now a staple of many Americans' diets. Advertising campaigns from the snack food companies,

often featuring sports stars, send the message that we can neutralize any negative effects of consuming their products simply by getting more physical exercise. But recent studies show a lack of exercise is not to blame for rising obesity rates. Bad diets are.

Interventions (干预) to help reduce junk food consumption are especially important for children and teenagers. Prevention is better than cure because obesity is so difficult to treat. Unfortunately, while health education has shown some success among young children, teens have been harder to reach.

Now a large-scale study has tried an innovative approach to change teenagers5 attitudes towards healthy eating, and the results are promising. The researchers argued that previous interventions have probably been unsuccessful because of a major flaw: they focused on a future, healthier you and assumed that this would be enough motivation for teenagers. In contrast, the new intervention cleverly exploits teenagers5 instinct for rebelliousness and autonomy, and the value they place on social justice.

To do this, researchers had students read an article on the food industry. It revealed a secret about the manipulative and deceptive strategies used to make junk food more addictive and characterize the products as healthy. The article also explained how advertising campaigns specifically target very young and poor people, causing harm for these vulnerable groups. Afterwards, the participants read a fictional survey of teens who wanted to “fight back against the companies by buying and eating less processed food".

After the intervention, participants associated healthy eating with autonomy and social justice. The teenagers also rated healthy eating as being more appealing. Importantly, there were also some promising effects of the new intervention on actual behavior. A day later the students were offered a choice of snacks and drinks in a seemingly unrelated context. The teens chose healthy snacks and drinks (such as fruit or water) more often over unhealthy options (like biscuits and soda). Apparently associating a healthy diet with teenagers' own values seems to be a promising avenue to prevent obesity.