Working for snack food: Individual differences in the reinforcing value of snacks

Research has indicated that compared to normal-weight individuals, obese individuals show a preference for high-calorie fattening foods. What this preference entails though is not entirely clear. Not much support has been found for the notion that overweight/obese people simply like the taste of high-calorie foods better. In this study it was investigated whether high-calorie snacks are relatively more reinforcing for overweight/obese people compared to normal weight people. In the present study, 23 overweight/obese participants (mean age: 19.9; mean BMI: 28.8) and 32 normal-weight participants (mean age: 19.1; mean BMI: 22.3) performed a choice-task, in which they could work for points representing a highly liked high-calorie snack and a highly liked low-calorie fruit or vegetable. As the task proceeded more work was required for obtaining the snack points, whereas obtaining the fruit/vegetable points required minimal effort. As hypothesized, overweight/obese participants put more effort in obtaining snacks compared to normal weight participants, indicating that snacks are relatively more reinforcing for overweight/obese individuals when compared with normal-weight individuals.