Here, Hans Rudolph Berthoud describes how overweight, and obesity happen when our ancient appetite system, built for a time when calories could be scarce and food acquisition required work, has collided with the modern food environment.
Here, Kent Berridge describes the details of the progressive, pavlovian learning – incentive sensitization model. He describes subconscious wanting, triggered by reward-related cues that trigger the urge to obtain and consume (go and get) rewards. Berridge points to the midbrain mesolimbic system involving dopamine projections to the nucleus accumbens and other parts of the striatum.
Here is described that overeating, overweight and obesity can be explained as the Wanting system overriding fulness.
Here, Giles Yeo describes how, Genome-wide-association studies suggest a key role in the brain in weight regulation and specifically how neuronal pathways that control the hedonic aspects of food intake (wanting) have emerged as the major drivers of body weight for both monogenic and polygenic obesity.
Here, Eric Stice describes neuroimaging findings that suggest “that individuals at risk for obesity initially show hyper-responsivity of reward circuitry (wanting) to high-calorie food tastes, which theoretically drives elevated intake of such foods”.
Here, a meta-analysis of 22 brain activation imaging studies found that those with obesity “exhibit hyper-responsivity of the brain regions involved in taste and reward for food-related stimuli. Note these findings well support incentive sensitization model proposed originally by Berridge above.
Here, the incentive sensitization theory is supported in humans in a laboratory by examining the effect of environmental cues on eating behavior.