Neuroimaging studies conducted over the last decade have demonstrated that obese youth show differential neural responses to food cues than lean youth. Why is this? Studies probing potential risk factors have supported effects of genetics, and family-level influences such as parent obesity. However, one of the most powerful environmental influences on child obesity – socioeconomic status (SES) – has been ignored.
We sought to investigate the influence of household income on adolescents’ neural responses to pictures of high energy-density (ED) foods, low-ED foods, and non-foods, in a fed (480 kcal Boost) and fasted (0 kcal water) condition. Our sample contained 76 adolescents (40F, 36M) who varied in familial obesity risk (22 lean with lean mother; 20 lean with overweight mother; 33 overweight of whom 28 had overweight mother and 5 had lean mother), and socioeconomic characteristics (n=25 low income, <40k; n=24 medium income, 50-90k; n=27 high income, >90k). We also evaluated income group differences in relevant behavioral and environmental factors.
Income group differences were most pronounced for the food vs. non-food comparison in the fed state. In comparisons with the medium income group, the low income group demonstrated greater activation in occipital cortex and insula, and greater deactivation of the default mode network. The high income group showed greater activation of cerebellum and cuneus. Income groups did not differ significantly according to child BMI z score or weight status.
Adolescents from low income and high income households generate a differential pattern of neural responses to food cues than those from medium income households. These differences likely reflect a combination of factors including differential experience with the foods presented and differential attitudes and behaviors towards them, and could contribute to SES-related differences in eating behavior and rates of obesity and eating disorders.