'Do no harm' - the impact of an intervention for addictive eating on disordered eating behaviours in Australian adults: secondary analysis of the TRACE randomised controlled trial.

Background: Designing interventions to change addictive eating behaviours is a complex process and understanding the treatment effect on co-occurring disordered eating behaviours is of importance. This study aimed to explore treatment effects of the TRACE (Targeted Research for Addictive and Compulsive Eating) intervention for addictive eating on eating disorder psychopathology, binge eating, reward driven eating and grazing behaviours.

Methods: This study involved secondary analysis of data from a randomised control trial among 175 participants (18-85 yrs) endorsing ≥ 3 Yale Food Addiction Scale (YFAS) symptoms who were randomly allocated to (1) active intervention, (2) passive intervention, or (3) control group. Change in YFAS, EDE-Q 6.0, Binge Eating Scale, RED-X5 and Short Inventory of Grazing scores were assessed at 3-months (immediate post-intervention) and 6-months (3-months post-intervention) follow-up.

Results: Using Linear Mixed Models, from baseline to 3-months there was a significant reduction in eating disorder global scores in the active intervention [mean decrease - 0.6 (95% CI: -0.8, -0.4)], but not in the passive intervention [-0.2 (95% CI: -0.5, 0.1)] or control groups [-0.1 (95% CI: -0.3, 0.1)]. In the active and passive intervention groups there were significant reductions in reward driven eating [-3.8 (95% CI: -4.9, -2.7; -2.5 (95% CI: -3.9, -1.1), respectively], compulsive grazing (-1.8 (95% CI: -2.4, -1.3); -1.1 (95% CI: -1.7, -0.5), respectively] and non-compulsive grazing scores (-1.4 (95% CI: -1.9, -1.0); -1.1 (95% CI: -1.7, -0.4), respectively], but not in the control group. The reduction in binge eating scores over time was similar for all groups. The reduction in addictive eating symptoms from baseline to 3-months was positively associated with the reduction in eating disorder global scores, binge eating, reward driven eating and grazing behaviours (r ranged from 0.23 to 0.69).

Conclusion: The dietitian-led TRACE intervention which adopted a weight-neutral, harm reduction approach for the management of addictive eating in adults demonstrated positive effects on some co-occurring disordered eating behaviours. Importantly the intervention did not cause any adverse changes in the eating disorder pathologies measured.

Trial Registration: Australia New Zealand Clinical Trial Registry ACTRN12621001079831.