Relation of neural response to palatable food tastes and images to future weight gain: Using bootstrap sampling to examine replicability of neuroimaging findings

Abstract

Because understanding neural vulnerability factors that predict future weight gain may guide the design of more effective obesity prevention programs and treatments, we tested whether neural response to palatable food tastes and images predicted future weight gain. We recruited 135 initially healthy weight adolescents, to reduce the possibility that a history of overeating affected neural responsivity, had them complete fMRI paradigms examining neural response to tastes of milkshakes that varied in fat and sugar content and images of palatable foods, and assessed BMI annually over a 3-year follow-up. We used a novel bootstrapping analytic approach to investigate the replicability of the fMRI findings. Whole-brain analyses indicated that lower response in the pre-supplemental motor area to high-fat/low-sugar milkshake taste predicted future BMI gain in the full sample and in 5 out of the 10 bootstrap samples. Elevated response in the precentral gyrus/Rolandic operculum to images of appetizing foods predicted future BMI gain in the full sample and in 4 out of the 10 bootstrap samples. Other peaks that emerged in the full sample did not replicate in most of the bootstrap samples, suggesting they were not reliable. Region of interest analyses did not replicate the predictive effects of peaks reported in past papers that used similar paradigms, including the evidence that TaqIA polymorphism moderated the relation of striatal response to palatable food tastes to future weight gain. Results suggest that lower responsivity of a region implicated in motor processing in response to palatable taste was associated with greater BMI gain over time, and further that bootstrap sampling may be useful for estimating the replicability of findings that emerge from whole brain analyses or regions of interest analyses with the full sample.

Figure 1.

BOLD activity in the pre-Supplemental Motor Area (pre-SMA; MNI: −3, 18, 54, Z = 4.89, k = 50) to the high-fat/low-sugar milkshake receipt > tasteless solution contrast is negatively associated with BMI gain over 3-year follow-up. The SPM in this figure and all others is threholded at p>0.001; k ≥32. The color bars represent t-values. The effects remained significant when excluding the outlier.

Figure 2.

BOLD activity in the pre-SMA to the high-fat/low-sugar milkshake receipt > tasteless solution contrast in 5 of the 10 subsamples.

Figure 3.

BOLD activity in the left precentral gyrus (MNI: −42, −9, 27, Z = 4.79, k = 72), extending into left Rolandic operculum to the appetizing food pictures > glasses of water contrast is positively associated with BMI gain over 3-year follow-up. The effects remained significant when excluding the outlier.

Figure 4.

TaqIA significantly moderated the effects of neural activation in the left pre-SMA (MNI coordinates: −3, 18, 54) in response to high-fat/low-sugar milkshake receipt > tasteless solution receipt on BMI gain. The interactive effects suggest that blunted pre-SMA activation in response to high-fat/low-sugar milkshake vs tasteless solution predicted greater BMI gain in A1 (r = −0.53, p<0.001) than A2/A2 carriers (r = −0.36, p<0.01).