Objective: There is considerable hope that genetic susceptibility testing will motivate behavior that can prevent or reduce the risk of complex conditions such as obesity. This study examined potential behavioral consequences of such testing.

Methods: Participants (n = 249) were randomly assigned to review one of four vignettes that asked them to imagine that they had been tested for their risk of becoming overweight or obese. The experimental factors were test type (genetic versus hormone test) and risk level (increased versus average risk for obesity). Study measures included behavioral intentions and perceived behavioral control related to eating a healthy diet, as well as weight locus of control.

Results: Participants assigned to the increased risk conditions indicated greater intentions to eat a healthy diet compared with participants assigned to the average risk conditions (P < 0.02). There were significant interaction effects of risk x perceived behavioral control (P < 0.02) and risk x weight locus of control (P < 0.003) on dietary intentions. Individuals with low perceived behavioral control or an external weight locus of control who were told to imagine they were at average risk expressed significantly lower intentions to eat a healthy diet. A three-way interaction of body mass index, family history of overweight/obesity, and assigned risk level found the greatest effects of risk feedback among those who either had a family history or a higher body mass index (P < 0.007).

Conclusion: This study provides preliminary evidence that testing for susceptibility to obesity may motivate healthier behavior. However, some individuals may be susceptible to a false reassurance effect after receiving test results indicating a lack of increased risk.