Investigating the effect of intermittent fasting (time-restricted eating) with and without calorie restriction compared to calorie restriction on anthropometric parameters, depression score, and metabolic factors in patients with major depression disorder and obesity: a study protocol for a randomized controlled trial.

It is suggested that intermittent fasting, specifically time-restricted eating (TRE), may have potential impact on depression in obese patients with major depression disorder (MDD). This study will aim to evaluate the effects of TRE with and without calorie restriction, compared to the traditional calorie restriction in patients suffering from MDD and obesity. This single-center, single-blinded, prospective, randomized trial will be conducted on 90 obese patients with major depression over 24 weeks. Participants were randomly divided into three groups in a 1:1:1 ratio. Group 1: recipients of TRE with 8-h food intake restriction (fixed 8-h time period), 2: recipients of TRE (fixed 8-h time period) and calorie restriction (75% of required calories), and 3: group receiving calorie restriction (75% of required calories). The primary objective is assessment of changes in depression severity scores, alongside secondary outcomes including changes in parameters such as body weight, body mass index (BMI), waist circumference, fat mass, fat-free mass, circadian rhythm score, quality of life, physical activity, and key metabolic factors such as fasting glucose levels, serum insulin, hemoglobin A1C, insulin resistance and sensitivity, lipid profile, and blood pressure. While calorie restriction can promote weight loss, its long-term adherence and mental health effects remain inconsistent. Emerging approaches like TRE have shown promise in improving body weight and metabolic parameters, but their impact on mental health is less understood. This study aims to fill this gap by comparing time-restricted eating with a fixed 8-h eating window plus and minus calorie restriction, against standard calorie restriction, in obese patients with major depressive disorder. The findings could have significant clinical implications for integrated management of obesity and depression. Iran Clinical Trials Registry, IRCTID: (https://irct.behdasht.gov.ir/IRCT20241029063543N1). Registered on 26-11-2024.