Voxel-based morphometry reveals brain gray matter volume changes in successful dieters

Abstract

Objective: To compare regional brain volume predictors of percent weight loss (WL) in dieters with obesity (DwO) and in the same participants categorized as "successful" (≥7% WL) or "unsuccessful" dieters (<7% WL).

Methods: DwO (n = 72) and participants with healthy weight (n = 22) completed a structural MRI at baseline and 3 months. All DwO participants were enrolled in a 12-week program consisting of a reduced calorie diet, increased physical activity, and behavioral modification. SPM8-based voxel-based morphometry processing streams were used for measurements of regional gray (GMV) and white matter volume and longitudinal changes in volume. Correlations between WL and baseline brain volume and change in brain volume, as well as differences between groups, were then tested.

Results: %WL was positively correlated with baseline GMV in right parahippocampal and orbitofrontal gyri in DwO. Successful dieters showed greater GMV loss in the left precentral gyrus and the insula compared with unsuccessful dieters. A negative correlation was found between %WL and GMV change from baseline in the left prefrontal regions.

Conclusions: Findings illustrate that WL is related to volumetric changes in brain areas previously linked to interoception and food motivation.

Trial registration: ClinicalTrials.gov NCT02031848.

© 2016 The Obesity Society.

Figures

Figure 1

Consort flow diagram shows the number of participants at enrollment, allocation, follow-up and analysis.

Figure 2

The three columns display statistical parametric maps of regions where percent weight loss was significantly correlated with higher baseline regional GMV (A and B) and regional WMV (C) from VBM analysis, displayed on a standardized spatially normalized MRI. Column A shows significant findings in a right parahippocampal gyrus cluster overlaid on sagittal and axial (lower) views (24, 8, −24). Column B shows significant findings in a right orbitofrontal gyrus cluster overlaid on sagittal and axial (lower) views (33, 36, −15). Column C shows significant findings in a left orbitofrontal/inferior frontal cortex (upper and lower; −38, 24, −9) and right fusiform gyrus (lower; 38, −55, −12). Coordinates given in MNI, color bars represent Z scores from SPM8 analysis, SPM8 maps threshold and displayed at p<.05 fwe corrected clusters> 100.

Figure 3

Linear relationship between percent weighy loss in dieting indiciduals with obesity and decrease in gray matter over 3 months in the left precentral gyrus.