Two small studies, in the journal Obesity, suggest that advertising campaigns to promote physical activity may have an unintended and unexpected consequence – they can make people want to eat more.
In the separate studies, groups of about 50 university students were exposed to physical-activity messaging – in the first test, they looked at posters from an exercise campaign (and the control group looked at posters that did not mention exercise); in the second test they took part in a computerised test that exposed them to active words used in advertising (e.g. ‘active’, ‘go’) with the control group exposed to neutral words (e.g. ‘pear’, ‘moon’). In both tests they were then offered food (raisins in the first test; peanuts, raisins and M&Ms in the second) – and in both tests those who had been exposed to the action words ate more (half as much again – 18 calories, as opposed to 12 – in the first study).
Obesity notes that ‘compensatory behavioral and metabolic mechanisms triggered by physical activity’ lead to this ‘unsatisfactory’ result, and notes that ‘these inadvertent effects may explain the limited efficacy of exercise-promotion programs for weight loss, particularly when systematic dietary guidelines are absent’. The lead author, Dolores Albarracin, a professor of psychology at the University of Illinois, pointed out that the context of messaging is important: ‘When the setting of the advertising is more conducive to eating than exercise, people eat.’
Source: New York Times, 5 March 2009.