Improving Assessment of the Spectrum of Reward-Related Eating: The RED-13

Abstract

A diversity of scales capture facets of reward-related eating (RRE). These scales assess food cravings, uncontrolled eating, addictive behavior, restrained eating, binge eating, and other eating behaviors. However, these scales differ in terms of the severity of RRE they capture. We sought to incorporate the items from existing scales to broaden the 9-item Reward-based Eating Drive scale (RED-9; Epel et al., 2014), which assesses three dimensions of RRE (lack of satiety, preoccupation with food, and lack of control over eating), in order to more comprehensively assess the entire spectrum of RRE. In a series of 4 studies, we used Item Response Theory models to consider candidate items to broaden the RED-9. Studies 1 and 2 evaluated the abilities of additional items from existing scales to increase the RED-9's coverage across the spectrum of RRE. Study 3 evaluated candidate items identified in Studies 1 and 2 in a new sample to assess the extent to which they accounted for more variance in areas less well-covered by the RED-9. Study 4 tested the ability of the RED-13 to provide consistent coverage across the range of the RRE spectrum. The resultant RED-13 accounted for greater variability than the RED-9 by reducing gaps in coverage of RRE in middle-to-low ranges. Like the RED-9, the RED-13 was positively correlated with BMI. The RED-13 was also positively related to a diagnosis of type 2 diabetes as well as cravings for sweet and savory foods. In summary, the RED-13 is a brief self-report measure that broadly captures the spectrum of RRE and may be a useful tool for identifying individuals at risk for overweight or obesity.

Keywords: assessment; eating behavior; item response theory; obesity; reward-driven eating; reward-related eating; uncontrolled eating.

Figures

FIGURE 1

Person-item map and histogram depicting thresholds on the spectrum of reward-related eating (RRE) for Study 1. The histogram at top displays the locations of participants on the latent RRE construct. The top row of the person-item map at bottom depicts the locations of the gaps in coverage of the RRE construct left by the RED-9. The 27 items listed below “thresholds of RED items” are ordered by the average of their thresholds’ values, and colored by the respective scale from which they originate. Circles depict each threshold, i.e., location on the RRE construct where people are most likely to move from one response option to the next. Gray rectangles appear whenever the gap between two consecutive RED-9 item thresholds is wider than 0.29 units. The gray rectangle only highlights parts of the latent trait that are further than 0.29/2 units from any RED-9 threshold. This figure includes the RED-9 items and all items that account for variance in the gap areas. See Supplementary Figure S1 for a figure with all items tested.

FIGURE 2

Person-item map and histogram depicting thresholds on the spectrum of RRE for Study 2. See Figure 1 note. Some items are shortened for graphical presentation. This figure includes the RED-9 items and the 37 items that account for variance in the gap areas. See Supplementary Figure S2 for a figure with all items tested.

FIGURE 3

Person-item map and histogram depicting thresholds on the spectrum of RRE for Study 3. See Figure 1 note. This figure includes the RED-9 items the 21 items that account for variance in the gap areas. For a graph on all items tested, see Supplementary Figure S3. Stars indicate items selected by authors for inclusion in Study 4.

FIGURE 4

Person-item map and histogram depicting thresholds on the spectrum of RRE for Study 4. See Figure 1 note. Bars in darker gray indicate gaps in RRE coverage left by the RED-13. Bars in lighter gray indicate gaps in coverage left by RED-9. Stars indicate items added to the RED-9 to form the RED-13.