Despite the overwhelming evidence that increased physical activity is associated with cardiovascular health, a sedentary lifestyle continues as the norm for most obese individuals. This self-defeating lifestyle is difficult to understand. So what is going on here?

Our brains are hard wired to preserve energy, even if it means circling around a parking lot waiting for a parking spot near the mall or store entrance.

The lack of effective real world interventions for increasing physical activity levels among obese individuals is confounding because on one hand, increased physical activity is perhaps the most accessible and cost effective disease prevention and intervention modality known. I have often thought that food, sugar, and fat was addicting…and it was too bad exercise was not very reinforcing. For the obese person, exercise may be painful or not possible. The authors tackle this conundrum by suggesting a lack of understanding of the cellular and molecular mechanisms underlying obesity and the inability for obese people to adhere to a prescribed activity plan. Physical inactivity is associated with functional changes in the basal ganglia, providing a neurobiological explanation for the sedentary lifestyle among obese persons.

Why Does This Matter?

Despite a wide expert consensus that the obese should exercise more, the adherence rate to even prescribed increases of physical activity is nearly null. This study suggests that it is not the patient’s fault. We agree. Impairments in dopamine signaling play a role in obesity, and also treatment resistance. Chronic exposure to obesogenic diets has been linked to impairments in dopamine synthesis, release, and receptor function, particularly in the striatum. Striatal dopamine is necessary for various activities, numerous survival functions and, the proper control of movement. By identifying the biological determinants of physical inactivity, we may learn more about more effective strategies for increasing healthy activity in people with and without this disease.