Exploring the hypothesis that deficits in reward processing may contribute to obesity by making it difficult for certain individuals to stop eating once their energy needs are met—either because they are prewired with faulty reward systems or because “excessive consumption of palatable food can drive reward dysfunction”—researchers from the Scripps Research Institute examined how prolonged access to a high-fat diet influenced brain reward systems in rats. The study published online this week in the journal Nature Neuroscience included several experiments that examined how rats’ eating habits and reward systems (dopamine receptors) were effected by unlimited access to high-fat foods (including bacon, sausage, cheesecake and other items). The researchers found that rats with access to an unlimited high-fat diet were far more likely to overeat, get the majority of their calories from the high-fat foods—despite equal access to rat chow—and gain significantly more weight than those with restricted access to the junk food, or access only to rat chow.
