Fat Intake and Deprivation Induced Hyperactivity as a Measure of Stress Management in HiS and LoS Rats

In response to stress, those with bulimia nervosa tend to binge on high fat food. Women who suffer from bulimia nervosa have been shown to manage stress poorly. Binge eating may become an unhealthy coping strategy as comfort food can provide emotional relief and therefore teach that eating can alleviate stress and boredom. This may negatively reinforce binge eating as a way to reduce negative emotions. We used a rodent model to explore this hypothesis. We looked at the way in which a high fat diet, versus a diet of regular rat chow, may affect HiS and LoS rats? deprivation induced hyperactivity (DIH) and startle amplitude, both measures of stress management. Selectively bred rats who differ in vulnerability to stress are used to model individual differences in people. Over ten days the rats were fed rat chow with corn oil or mineral oil. After six days the rats underwent a 48 hour period of deprivation, with a one hour meal after the first 23 hours. Before returning to ad lib feeding, the rats were startle tested. Preliminary results suggest that the high fat diet increases, rather than attenuates, DIH and startle amplitude. The rats that were fed the high fat diet appeared to run more during the 48 hour deprivation period. The previously reported line difference between the HiS and LoS rats in startle amplitudes, with the LoS rats hyperstartling, was replicated. Both lines of rats fed the high-fat diet appeared to startle more. Fat then seems to decrease rather than increase the rat?s ability to cope with stress effectively, contrary to our hypothesis