Friday, April 16, 2010

Beware of the dangers of stressful eating...

So you have submitted your taxes (Hurray!) and now can breathe a sigh of relief. In stressful moments or shortly following stressful moments, we often turn to foods that are high in fat or sugar or both to gain a sense of relief.

Recent research suggests we may be doing more damage than good. In a study published in Nature Neuroscience, a research group at the Scripps Research Institute in Florida, examined the effects of high caloric foods on dopamine signaling in rats. The premise of their research lies in the observation that obese individuals continue to eat food even after obtaining the calories needed for their energy needs. To paraphrase their question, "What is the mechanism that drives people to continues in a compulsive behavior?" They looked for inspiration in one area that shares a similar behavior pattern, drug addiction.

So - this group took a group of rats implanted an electrode in their brains and trained the rats to reward themselves via an electrical stimulation in response to their eating habits. They then divided the rats into three groups based on the amount of time they were exposed to the high fat chow (no access, restricted access and extended access). The rats that had the most access to the high fat chow quickly gained weight. The restricted access group tended to be heavier but not enough to be considered statistically significant. What was interesting was that has the rats in the extended access group got heavier, the brain stimulation reward (BSR - the training via electrical stimulation) threshold got higher - meaning they needed to eat more to reward themselves.

Further examination of the feeding behaviors among the three groups was illuminating. The groups who had access to the high fat chow shifted their preference of food by eating more calories from the high fat food. The restricted group shifted 67% of their caloric intake to the high fat food and the extended access group ate 95% of their calories from the high fat food. The results show that the rats tried to eat as much of the high fat food as possible, a pattern of eating known as binge eating.

Another results showed that as the rats got heavier, the density of the D2R (membrane dopamine receptors - these are receptors responsible for binding the neurotransmitter dopamine and signaling a reward response) decreased. This resulted in more high fat chow needing to be consumed in order to trigger the same reward response.

The last result I'll discuss was with a fresh group of trained no access, restricted access and extended access group of rats. These rats were then granted equal access to the high fat chow. However, half of each group was exposed to a light cue and then "punished" via an electric foot shock, while the other half was left alone. The light cue seemed to have no effect in deterring the groups from their behaviors. However, when combined with the foot shock, the no access group and the restricted access group significantly reduced their caloric intake from the high fat chow. The extended access, overweight group was resistant to both the light cue AND the foot shock. They ate right through their punishment. WOW!

Now there are more results from this study that show some strong evidence for food being a trigger for additive behavior. In particular, foods that are high in fat, high in sugar and salt - foods that are deemed "palatable". In times of stress we need to ask the question - why am I eating this food? Am I hungry? Am I trying to divert my attention from a particular traumatic event? Ask these honest questions. If you are hungry - eat an apple. Decide prior to the event what you will eat and when you will eat it. A great way to relieve stress is by exercising - go for walk. Get on your bike but DON"T BINGE EAT. Keep to your eating schedule. Maintaining a regular eating schedule will help in your moments of crisis because you have already committed to the schedule. We would love to hear how you deal with stress. Post your comments or send us an email at science@unicity.net

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