Differential functional magnetic resonance imaging response to food pictures in successful weight-loss maintainers relative to normal-weight and obese controls

Abstract

Background: Prior research indicates that successful weight-loss maintainers (SWLs) work harder than people of normal weight to maintain their weight loss, including greater dietary restriction of fat and higher physical activity levels. However, little work to date has examined how SWLs differ biologically from normal-weight (NW) and obese controls.

Objective: The objective was to compare the brain responses of SWLs to food pictures with those of NW and obese controls.

Design: Blood oxygen level-dependent responses to high- and low-energy food pictures were measured in 18 NW controls, 16 obese controls, and 17 SWLs.

Results: Group differences were identified in 4 regions, which indicated significant change in activation in response to the food pictures. SWLs showed greater activation in the left superior frontal region and right middle temporal region than did NW and obese controls-a pattern of results confirmed in exploratory voxel-wise analyses. Obese controls also showed greater activation in a bilateral precentral region.

Conclusions: These results suggest that SWLs show greater activation in frontal regions and primary and secondary visual cortices-a pattern consistent with greater inhibitory control in response to food cues and greater visual attention to the food cues. A greater engagement of inhibitory control regions in response to food cues as well as a greater monitoring of foods may promote control of food intake and successful weight-loss maintenance.

FIGURE 1

The food cue reactivity paradigm.

FIGURE 2

Clusters of significant activation in response to low-energy or high-energy food (t test, P < 0.001). Pictures in numerical order from the largest cluster of activation: 1, left middle occipital/Brodmann area (BA) 18; 2, right inferior occipital/lingual gyrus; 3, superior frontal/bilateral cingulate; 4, left inferior parietal; 5, left middle occipital; 6, right inferior and superior parietal/precuneus; 7, left superior frontal; 8, left precuneus; 9, right middle frontal; 10, left middle temporal; 11, right middle temporal; 12, left inferior frontal; 13, right precentral/BA 6; and 14, left precentral/inferior frontal/BA 6.

FIGURE 3

Mean (±SEM) changes in the blood oxygen level–dependent signal during blocks of low-energy and high-energy food picture cues relative to blocks of neutral pictures in the significant clusters of activation in the left superior frontal region [A: n = 18 normal-weight (NW) subjects, 16 obese (Ob) subjects, and 17 successful weight-loss maintainers (SWL); repeated-measures ANOVA: group P = 0.02; Bonferroni-adjusted post hoc comparison: P = 0.04 between Ob and SWL, P = 1.0 between Ob and NW, and P = 0.07 between NW and SWL; no significant group × task interaction] and in the right middle temporal region (B: n = 18 NW, 16 Ob, and 17 SWL; repeated-measures ANOVA: group P = 0.04; Bonferroni-adjusted post hoc comparison: P = 0.12 between Ob and SWL, P = 1.0 between Ob and NW, and P = 0.07 between NW and SWL; no significant group × task interaction).

FIGURE 3

Mean (±SEM) changes in the blood oxygen level–dependent signal during blocks of low-energy and high-energy food picture cues relative to blocks of neutral pictures in the significant clusters of activation in the left superior frontal region [A: n = 18 normal-weight (NW) subjects, 16 obese (Ob) subjects, and 17 successful weight-loss maintainers (SWL); repeated-measures ANOVA: group P = 0.02; Bonferroni-adjusted post hoc comparison: P = 0.04 between Ob and SWL, P = 1.0 between Ob and NW, and P = 0.07 between NW and SWL; no significant group × task interaction] and in the right middle temporal region (B: n = 18 NW, 16 Ob, and 17 SWL; repeated-measures ANOVA: group P = 0.04; Bonferroni-adjusted post hoc comparison: P = 0.12 between Ob and SWL, P = 1.0 between Ob and NW, and P = 0.07 between NW and SWL; no significant group × task interaction).

FIGURE 4

Mean (±SEM) changes in the blood oxygen level–dependent signal during blocks of low-energy and high-energy food picture cues relative to blocks of neutral pictures in the significant clusters of activation in the right precentral region [A: n = 18 normal-weight (NW) subjects, 16 obese (Ob) subjects, and 17 successful weight-loss maintainers (SWL); repeated-measures ANOVA: group P = 0.05; Bonferroni-adjusted post hoc comparison: P = 0.07 between Ob and SWL, P = 0.16 between Ob and NW, and P = 1.0 between NW and SWL; no significant group × task interaction] and in the left precentral region (B: n = 18 NW, 16 Ob, and 17 SWL; repeated-measures ANOVA: group P = 0.04; Bonferroni-adjusted post hoc comparison: P = 0.04 between Ob and SWL, P = 0.25 between Ob and NW, and P = 1.0 between NW and SWL; no significant group × task interaction).

FIGURE 4

Mean (±SEM) changes in the blood oxygen level–dependent signal during blocks of low-energy and high-energy food picture cues relative to blocks of neutral pictures in the significant clusters of activation in the right precentral region [A: n = 18 normal-weight (NW) subjects, 16 obese (Ob) subjects, and 17 successful weight-loss maintainers (SWL); repeated-measures ANOVA: group P = 0.05; Bonferroni-adjusted post hoc comparison: P = 0.07 between Ob and SWL, P = 0.16 between Ob and NW, and P = 1.0 between NW and SWL; no significant group × task interaction] and in the left precentral region (B: n = 18 NW, 16 Ob, and 17 SWL; repeated-measures ANOVA: group P = 0.04; Bonferroni-adjusted post hoc comparison: P = 0.04 between Ob and SWL, P = 0.25 between Ob and NW, and P = 1.0 between NW and SWL; no significant group × task interaction).