The scale matters: assessing body size with figure rating scales in a diverse sample of young adults.

PURPOSE

To explore intersectional differences in weight perception accuracy in a diverse sample of young adults using CDC-defined weight status labels and four separate figure rating scales (FRS).

METHODS

This cross-sectional study of 322 18-25-year-olds with body mass index (BMI) ranging from 18.5 to 57.2 (M = 26.01, SD = 6.46) enrolled participants as part of a larger university subject pool cohort in the U.S. MidSouth. Height and weight measurements were obtained. Participants (55% Black, 45% white; 74% female) selected images that best represented their current body size using four FRS and described their weight perception using five labels from "very underweight" to "very overweight/obese". Receiver operating characteristic (ROC) curve analyses were used to compare variability in classification of weight status by FRS and weight perception category across gender and race.

RESULTS

Area under the curve (AUC) statistics indicated all scales were significantly better at classifying weight status than chance. Among Black females and Black males, the culturally adapted scale had the strongest discriminatory ability [(AUC = 0.93, SE = 0.02, p < 0.001, 95% CI = 0.89-0.97) and (AUC = 0.93, SE = 0.04, p < 0.001, 95% CI = 0.86-1.00), respectively]. Among white females, the silhouette scale had the strongest discriminatory ability (AUC = 0.93, SE = .03, p < 0.001, 95% CI = 0.88-0.99). Among white males, the photo-based scale had the strongest discriminatory ability (AUC = 0.84, SE = 0.06, p = 0.001, 95% CI = 0.71-0.96). Across all groups, weight perception labels were the weakest classifier of weight status.

CONCLUSION

Weight perception labels are an ineffective method of assessing weight status and FRS accuracy varies by race and gender, suggesting the value of gender- and culturally tailored scales.

LEVEL OF EVIDENCE

Level III. Evidence obtained from well-designed cohort or case-control analytic studies.