Psychological aspects of grazing in adolescents: Psychometric properties and measurement invariance of the Rep(eat)-Q in community and clinical samples.

BACKGROUND

Grazing is a disordered eating behavior associated with poor weight control, increased eating disorder psychopathology, and psychological difficulties in adults. Unfortunately, little is known about grazing in adolescence, which is aggravated by the lack of validated measures for this population. This study investigates the psychological aspects of grazing in adolescence and provides psychometric support for a brief self-report measure, the Rep(eat)-Q.

METHODS

A community sample of middle/high school students (n = 358, 55.6% females) and a clinical sample with overweight/obesity (n = 204, 59.8% females), completed a set of self-report questionnaires assessing eating and psychological variables including the Rep(eat)-Q. Weight and height data were also collected (Community: Mz-BMI = 0.39, SD = 0.98; Clinical: Mz-BMI = 2.39, SD = 0.74).

RESULTS

Confirmatory factor analysis revealed an adequate fit [(χ2(107) = 389.77; p < 0.001; CFI = 0.99; TLI = 0.99; NFI = 0.99; SRMR = 0.062; RMSEA = 0.098] for a second-order (grazing) model with two first-order factors (repetitive eating and compulsive grazing subscales) with good reliability (0.85 < α < 0.91). Metric and scalar invariance were confirmed, allowing comparisons between samples. Compared with clinical adolescents, community adolescents reported higher scores on the Rep(eat)-Q total (Community: M = 1.86, SD = 1.30; Clinical: M = 1.53, SD = 1.35; t(559) = - 2.81; p = 0.005) and repetitive eating subscale (Community: M = 2.04, SD = 1.44; Clinical: M = 1.52, SD = 1.35; t(560) = - 4.24; p ≤ 0.001). The Rep(eat)-Q total score and subscales scores were significantly positively correlated with eating disorder psychopathology and inversely correlated with intuitive eating, suggesting good convergent validity (0.11 < r < 0.63). Similarly, adolescents scoring higher on grazing also present more psychological distress and poor cognitive and emotional functioning (0.15 < r < 0.50). Psychological variables (i.e., depression, anxiety, and negative urgency) explained 21.8% of the variance in the grazing score, independent of sex, age, and BMI z-score [F(6, 490) = 22.87, p ≤ 0.001; R2 = 0.218].

CONCLUSIONS

The Rep(eat)-Q is a reliable self-reported measure for assessing grazing in adolescents. These findings provide further support for the conceptualization of grazing in the spectrum of disordered eating and psychopathology in adolescents.