The interaction between impulsivity and a varied food environment: its influence on food intake and overweight

Objective: The current study tests the influence of two factors, the obesogenic environment and impulsivity, on food intake in primary school children. Our current food environment offers a large variety of cheap and easily available sweet and fatty foods. This obesogenic environment is believed to be a cause of the recent obesity epidemic. Impulsive people are generally less successful at inhibiting prepotent responses and they are reward sensitive. We investigate whether the interaction between an obesogenic environment and an impulsive person leads to overeating. Design: A quasi- experimental 2 ( reward sensitive versus not reward sensitive) by 2 ( successful response inhibitors versus unsuccessful response inhibitors) by 2 ( monotonous versus varied food environment) between- subjects design with caloric intake during a taste test as the main dependent variable. The link between impulsivity and overweight was also examined. Subjects: 78 healthy primary school children ( age: 8 - 10 years). Measurements: We measured two aspects of impulsivity: reward sensitivity and deficient response inhibition. Subsequently, one aspect of the obesogenic environment was manipulated; half of the participants received monotonous food during a bogus taste test whereas the other half tasted food that was varied in colour, form, taste and texture. Results: As expected, reward sensitivity interacted with variety. In the monotony group there was no difference in food intake between the less and more reward- sensitive children ( 183 kcal +/- 23 s. d. versus 180 kcal +/- 21 s. d.). However, in the variety group the more reward- sensitive children ingested significantly more calories than the less reward- sensitive children ( 237 kcal +/- 30 s. d. versus 141 kcal +/- 19 s. d.). Reward sensitivity was not linked to overweight. Deficient response inhibition did not interact with variety, but it was linked to overweight. Conclusion: It is suggested that reward sensitivity could be a causal mechanism for overeating in an obesogenic environment whereas prepotent response inhibition may be a maintaining factor of the problem of overeating