Effects of Anxiety on Caloric Intake and Satiety-Related Brain Activation in Women and Men

Abstract

Objective: To test the relationship of anxiety to caloric intake and food cue perception in women and men.

Methods: Fifty-five twins (26 complete, 3 incomplete pairs; 51% women) underwent 2 functional magnetic resonance imaging (fMRI) scans (before and after a standardized meal) and then ate at an ad libitum buffet to objectively assess food intake. State and trait anxiety were assessed using the State-Trait Anxiety Inventory. During the fMRI scans, participants viewed blocks of fattening and nonfattening food images, and nonfood objects.

Results: In women, higher trait anxiety was associated with a higher body mass index (BMI) (r = 0.40, p = .010). Trait anxiety was positively associated with kilocalories consumed at the buffet (r = 0.53, p = .005) and percent kilocalories consumed from fat (r = 0.30, p = .006), adjusted for BMI. In within-pair models, which control for shared familial and genetic factors, higher trait anxiety remained associated with kilocalories consumed at the buffet (p = .66, p = .014), but not with BMI. In men, higher state anxiety was related to macronutrient choices, but not to total caloric intake or BMI. FMRI results revealed that women with high trait anxiety did not suppress activation by fattening food cues across brain regions associated with satiety perception after eating a standardized meal (low anxiety, mean difference = -15.4, p < .001; high anxiety, mean difference = -1.53, p = .82, adjusted for BMI).

Conclusions: In women, trait anxiety may promote excess caloric consumption through altered perception of high-calorie environmental food cues, placing women with genetic predispositions toward weight gain at risk of obesity.

Trial registration: Clinicaltrials.govidentifier:NCT02483663.

Conflict of interest statement

Conflicts of Interest: The authors have no conflicts of interest to report.

Figures

Figure 1. Sex-specific associations between trait and state anxiety and average nervousness rating (mm)

In women, average visual analog scale nervousness ratings were associated with A) trait anxiety, and B) state anxiety (from State-Trait Anxiety Inventory). In men, average nervousness ratings were associated with D) state anxiety only. P-values derived from generalized estimating equations and r-values from Pearson’s Product-moment correlation. Data are adjusted for BMI.

Figure 2. Sex-specific relationships between trait anxiety, BMI, emotional eating and ad libitum buffet intake

Associations in women are shown between trait anxiety and A) BMI (kg/m2), B) TFEQ-R18 emotional eating subscale scores and C) kilocalories consumed during the ad libitum buffet. In men, associations were not present between trait anxiety and D) BMI (kg/m2), E) TFEQ-R18 emotional eating subscale scores, or F) kilocalories consumed during the ad libitum buffet. P-values derived from generalized estimating equations and r-values from Pearson’s Product-moment correlation. TFEQ-R18 =Three-Factor Eating Questionnaire-Revised 18 item version; BMI=body mass index. Data are adjusted for BMI.

Figure 3. Sex-specific relationships between trait anxiety (women) or state anxiety (men) and macronutrient choice

In women, associations were present between trait anxiety and percentage of kilocalories consumed at the ad libitum buffet from A) fat and B) carbohydrates but not C) protein. In men, associations were present between state anxiety and percentage of kilocalories consumed from B) carbohydrates and C) protein; a trend was also present with A) fat. P-values derived from generalized estimating equations and r-values from Pearson’s Product-moment correlation. Trait and state anxiety scored derived from the State-Trait Anxiety Inventory (STAI); BMI=body mass index. Data are adjusted for BMI.

Figure 4. Associations of within-twin-pair differences in trait anxiety with total kilocalories consumed at the ad libitum buffet and BMI in women

After controlling for age, family background, and genetics (100% in MZ, 50% in DZ), trait anxiety was positively related to A) kilocalories (kcals) consumed during the buffet meal but not to B) BMI. Spearman’s rho and P-values derived from Spearman’s Rank Correlation Coefficient. BMI= body mass index.

Figure 5. Brain activation by visual food cues pre- and post-standardized meal in low and high anxiety women

Among low anxiety women, brain activation by fattening vs. non-fattening food cues was significantly suppressed by a standardized meal in each of the five ROIs (A–E bars on left, Nucleus Accumbens, Amygdala, Insula, Dorsal Striatum, and mOFC). Women with high anxiety did not show meal-induced changes in brain activation in any of the ROIs (A–E bars on right). Data are mean parameter estimates for each ROI ± SEM pre- (white bars) and post- (gray bars) standardized meal between low and high anxiety women (left bars and right bars, respectively). Bilateral regions (A–D) were averaged. P-values derived from generalized estimating equations. *P