Stress, reward, and cognition in the obese brain

Stress can increase appetite and impair cognitive control over reward-driven or “comfort” eating. Overweight and obese individuals experience high levels of personal and social stress and are more sensitive to the impact of these stressors. Therefore, understanding the impact of stress on motivation and cognition is crucial to explain the drivers of overweight and obesity. In this chapter, we summarize the neurobiological basis of the interaction between stress, appetite, and cognitive control systems and analyze the evidence on the impact of stress on food-related motivation and learning, higher-order cognition and eating behavior, as well as their implications for obesity. We observed significant impacts of acute and chronic stress on food cravings, unhealthy eating patterns, and cognitive control processes, to which overweight and obese individuals are disproportionately sensitive. These impacts are underpinned by inherent connections between brain regions implicated in stress and energy regulation and brain systems implicated in reward coding, emotional learning, and “self-control.” Stress seems to sensitize the response of reward and emotional systems to highly palatable food and to impair the prefrontal cortex and hippocampus inputs needed to regulate reward and emotion-driven overeating among people who are overweight and obese. Therefore, prevention and treatment strategies directed to reduce stress exposure and boost stress and cognitive regulation are promising avenues to tackle the current obesity epidemic.