Neural processing of healthy foods in normal-weight and overweight children and adults

Abstract

Childhood obesity is a growing problem almost everywhere in the world. The chance for an overweight child to become an overweight adult is much larger than for a normal-weight child, which emphasizes the importance of prevention. Weight gain, and thus overweight and obesity, is largely caused by overconsumption, which in turn is driven by food choices. These decisions on what, when, and how much to eat are made in the brain, which integrates a multitude of neural and hormonal signals arising in response to the body’s internal state and the environment. Understanding how the brain responds to food and how eating decisions are made in the brain, is crucial for elucidating the neural processes underlying maladaptive eating behaviors. This knowledge may provide novel approaches for the prevention of childhood obesity and for healthy eating interventions. In this thesis, how the brain responds to food is measured by functional Magnetic Resonance Imaging (fMRI). fMRI is a non-invasive neuroimaging technique which enables measuring which parts of the brain become more active when a certain task is performed. Food-related brain activation in children is expected to differ from that in adults because their brain is still developing. This applies in particular to the prefrontal cortex, which is among the last brain regions to mature and which is involved in the control of behavior and the inhibition of impulsive responses. The aim was to examine the neural responses to healthy and unhealthy food viewing and food choice in normal- and overweight children and adults. The conclusion of this thesis was that children had weaker brain responses related to cognitive control than adults when viewing unhealthy foods and when making food choices. Children who are overweight had even weaker responses in this area. This pattern of brain activation was accompanied by more unhealthy choices in children. Taken together, children in general and overweight children in particular may be more vulnerable to unhealthy foods in their environment and less able to resist unhealthy choice options. The results presented in this thesis make a strong case for decreasing the marketing of unhealthy foods directed at children and adapting the food environment to promote healthier choices.