The effects of time-restricted eating in comparison with energy-restricted diet on expression of BMAL-1 and miRNA-let-7f-1-3p genes, circadian rhythm status, sleep quality, metabolic and anthropometric markers in obese women: a study protocol for a r

INTRODUCTION: One of the most common chronic diseases is obesity. Disturbances in circadian rhythm and sleep quality are common in these people. Genes related to circadian rhythm control are also disrupted. One of the methods of controlling and reducing obesity is to intervene in the individual's diet, and one of the alternative methods to the conventional low-calorie diet is the use of fasting diets, including time-restricted eating (TRE), which can have effects on the expression of a circadian rhythm genes, the circadian rhythm status, and the quality of sleep. This randomized controlled trial (RCT) will be aimed to examine the effect of the TRE diet in comparison with an energy-restricted diet (ERD) on the expression of basic helix-loop-helix ARNT-Like-1 (BMAL-1) and micro ribonucleic acid (miRNA)-let-7f-1-3p genes, circadian rhythm status, and sleep quality in women with obesity. METHODS AND ANALYSIS: This study will be conducted on 42 obese women. Participants will be randomly assigned to receive either 16:8 TRE (fasting from 8 to 12 PM the next day) or an ERD (55% carbohydrate, 30% fat, 15% protein) diet for 12 weeks. Gene expression, circadian rhythm status, sleep quality, anthropometric measurements, and metabolic evaluations will be assessed before and after the intervention. Dietary evaluations will be performed at baseline, middle, and end of the study. DISCUSSION: Since circadian rhythm-related gene expression has a role in circadian rhythm and ultimately obesity regulation, it seems that TRE, as a dietary approach, can affect these gene expressions. TRIAL REGISTRATION: Iranian Registry of Clinical Trials (IRCT20100123003140N25), which was registered and approved on 28 July 2025 (https://irct.behdasht.gov.ir/user/trial/84484/view).