The Goldilocks Principle of Obesity

Both low dopamine and high dopamine states associated with overeating.
Uveal Blues
How pleasurable and desirable does this image of chocolate cake appear to you? 

Research has shown that the more tempting this cake looks to you, the greater the chances you’ll take a bite of real cake, followed by another bite, and another. Before you know it, you may eventually find yourself like 34% of U.S. adults -- obese. But what if I told you that viewing this picture as not rewarding enough might also lead you down the path too obesity? Interesting article discusses latest research in this regard here.


An exciting brain imaging and genetics study from the laboratory of Eric Stice at the Oregon Research Institute, recently published in the journal NeuroImage, has shown just that. Stice’s team had a group of adolescent girls imagine eating appetizing foods while viewing pictures of these foods. Over the following year, those whose brains showed less activation in areas known to respond to natural rewards like foods ended up gaining more weight -- though only if they had a particular genetic makeup.
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So both increased and decreased reward sensitivity could lead to obesity? One lab reconciled these seemingly disparate ideas by focusing on sensitivity to reward, a psychobiological trait assumed to be rooted in the dopamine reward system. If you’re a healthy weight or somewhat overweight, the more sensitive you are to rewards, the heavier you tend to be. But if you’re obese, the less sensitive you are to rewards, the heavier you tend to be. This is especially true as obesity becomes more extreme. Thus, it is possible that the relationship between reward neurocircuitry and obesity follows the Goldilocks principle – too much or too little reward system activation may lead to weight gain. In order to maintain a healthy weight, reward system activation needs to be ‘just right.’  

Might there be some tipping point, at which higher reward sensitivity gets eroded too far, into lower sensitivity? There could be a transition in obesity, as has been suggested for addiction,where overconsumption of appetizing foods is initially driven by reward, but then becomes less reward driven and more automatic and compulsive over time. This is a very interesting idea that warrants further investigation.