The boomerang effect of mandatory sanitary messages to prevent obesity

A variety of prevention measures are being adopted to counter obesity. One of them is to include health sanitary messages on advertisements for food products. We tested the efficacy of this type of measure in an experimental study with 131 participants who were randomly exposed to an advertisement for a hedonic product containing or not a sanitary message. Implicit memory representations (priming protocol), explicit attitudes (questionnaire) and a behavioral measure of food choice (healthy versus unhealthy snack) were collected. Results showed that participants associated negative concepts more easily to the product when the advertisement was presented without the sanitary message, while there were no differences in the explicit attitudes. Moreover, the choice of a healthy snack doubled in the absence of sanitary message. Contrary to its objectives, the obesity prevention sanitary message fills in consumers’ need for justification leading to a greater acceptability of the advertised product and increased choice of an unhealthy snack.