Is brain response to food rewards related to overeating? A test of the reward surfeit model of overeating in children

Abstract

The reward surfeit model of overeating suggests that heightened brain response to rewards contributes to overeating and subsequent weight gain. However, previous studies have not tested whether brain response to reward is associated with food intake, particularly during childhood, a period of dynamic development in reward and inhibitory control neurocircuitry. We conducted functional magnetic resonance imaging (fMRI) with 7-11-year-old children (n = 59; healthy weight, n = 31; overweight, n = 28; 54% female) while they played a modified card-guessing paradigm to examine blood-oxygen-level-dependent (BOLD) response to anticipating and winning rewards (food, money, neutral). Food intake was assessed at three separate meals that measured different facets of eating behavior: 1) typical consumption (baseline), 2) overindulgence (palatable buffet), and 3) eating in the absence of hunger (EAH). A priori regions of interest included regions implicated in both reward processing and inhibitory control. Multiple stepwise regressions were conducted to examine the relationship between intake and BOLD response to rewards. Corrected results showed that a greater BOLD response in the medial prefrontal cortex for anticipating food compared to money positively correlated with how much children ate at the baseline and palatable buffet meals. BOLD response in the dorsolateral prefrontal cortex for winning food compared to money was positively correlated with intake at the palatable buffet meal and EAH. All aforementioned relationships were independent of child weight status. Findings support the reward surfeit model by showing that increased brain response to food compared to money rewards positively correlates with laboratory measures of food intake in children.

Trial registration: ClinicalTrials.gov NCT02855398.

Keywords: Childhood obesity; Eating behavior; Inhibitory control; Reward processing; fMRI.

Figure 1

An overview of study enrollment.

Figure 2

Localization of (A) medial prefrontal cortex (mPFC) (x = 0, y = 52, z = 20). (B) Partial correlations between intake (kcal) at the baseline meal and BOLD response in the mPFC BOLD for anticipating food vs. money (β = 0.32, p = 0.009). (C) Localization of the left orbitofrontal cortex (x = −24, y = 32, z = −14). (D) Partial correlations between intake (kcal) at the baseline meal and BOLD response in the left orbitofrontal cortex (OFC) for anticipating food vs. money (β = 0.32, p = 0.008). Partial correlations are adjusted for BMI z-score.

Figure 3

Localization of the (A) right dorsolateral prefrontal cortex (dlPFC) (R1 x = 44, y = 38, z = 42; R2 x = 36, y = 38, z = −30). (B) Partial correlations between intake (kcal) during EAH and BOLD response in the right (R1) dlPFC for food vs. money (β = 0.42, p = 0.002). (C) Partial correlations between intake (kcal) during EAH and BOLD response in the right (R2) dlPFC for winning food vs. money (β = 0.38, p = 0.009). Partial correlations are adjusted for BMI z-score.

Figure 4

Localization of the (A) medial prefrontal cortex (mPFC) (x = 0, y = 52, z = 20). (B) Partial correlations between intake (in kcals) at the palatable buffet meal and BOLD response in the mPFC for anticipating food vs. money (β = 0.29, p = 0.02). (C) Localization of the left amygdala (x = −22, y = −4, z = −18). (D) Partial correlations between intake (in kcals) at the palatable buffet meal and BOLD response in the left amygdala for winning food vs. money (β = 0.36, p = 0.004). (E) Localization of the right dorsolateral prefrontal cortex (dlPFC) (R1 x = 44, y = 38, z = 42). (F) Partial correlations between intake (in kcals) at the palatable buffet meal and BOLD response in the R1 dlPFC for winning food vs. money (β = 0.39 p = 0.001). Partial correlations adjusted for BMI z-score.