Exploring the utility of N-acetylcysteine for loss of control eating: protocol of an open-label single-arm pilot study.

Background: A sense of loss of control over eating, such that eating occurs despite the intent not to, is common in people with obesity and eating disorders such as binge eating disorder and bulimia nervosa. Currently, options for management of loss of control eating are limited. We recently determined that the pro-drug N-acetylcysteine (NAC) reduces compulsive-like eating in a rat model of diet-induced obesity. We will now conduct a single site, open-label pilot study to examine the feasibility of a randomized controlled trial (RCT) of NAC for loss of control eating in humans.

Methods: Thirty-six adult volunteers with loss of control eating will be enrolled. All participants will receive NAC at a dose of 1200 mg orally twice daily for 12 weeks. Eating behaviors and triggers will be assessed before and after the NAC treatment period using questionnaires (Eating Loss of Control Scale, Palatable Eating Motives Scale: Coping Subscale, Food Craving Inventory, Reward-Based Eating Scale, Perceived Stress Scale, and Emotional Eating Scale) and ecological momentary assessment (EMA). The primary outcomes of this feasibility study are recruitment rate, participant retention rate at week 12, and medication adherence. The secondary outcome is change in Eating Loss of Control Scale score from baseline to week 12. Exploratory data will be collected on the change in eating behaviors from baseline to week 12. Although EMA can provide real-time data on eating behaviors compared with retrospective questionnaires, it relies on repeated daily measurement for long periods which can affect participant's adherence to study protocol. Therefore, this feasibility study will assess the performance of EMA versus retrospective questionnaires and will determine which approach suits the purposes of the research.

Discussion: The results of this study will inform the feasibility of a RCT of NAC for loss of control eating using EMA.

Trial Registration: This study was prospectively registered with the Australian and New Zealand Clinical Trials Registry in June 2022 (ACTRN12622000902796).