Objective:To investigate the effects of personalized intermittent energy restriction (IER) diet on sleep related gut microbiome in obese patients.Methods:In this single-arm clinical trial, a total of 35 obese patients who visited Henan Provincial People′s Hospital from April to November 2018 were recruited as research subjects. They underwent a strict 32-day IER diet intervention, divided into 4 stages of 8 days each. Nutritional recipes were formulated and nutritious meals were provided to each obese patient with timed meals, including 55% carbohydrates, 15% protein, and 30% fat per meal. In stages 1, 2, 3, and 4, patients were provided with 2/3, 1/2, 1/3, and 1/4 of their previous calorie intake every other day, respectively, with meals at 8:00 and 16:00. During the remaining time, patients were allowed unrestricted eating at home. Physiological indicators (weight, body mass index, body fat percentage, waist circumference, hip circumference, fasting blood glucose, glycosylated hemoglobin, blood pressure, triglycerides, total cholesterol, high-density lipoprotein, low-density lipoprotein and Pittsburgh Sleep Quality Index (PSQI) scores were observed before and after the intervention. Gut microbiota changes were analyzed using metagenomic sequencing technology, and Spearman′s correlation analysis was used to assess the correlation between significantly different bacterial species and PSQI scores.Results:After the intervention, the body weight, body mass index, and PSQI scores of obese patients were all significantly lower than before intervention [(89.92±14.98) vs (97.53±15.67) kg, (31.94±3.95) vs (34.64±4.05) kg/m 2, (3.43±1.16) vs (5.42±2.27)], the abundance of gut microbiota was significantly higher after the intervention (all P<0.05). There were 45 significantly different bacterial species before and after the intervention, of which 6 bacterial species ( Enterobacter cloacae, Escherichia coli, Odoribacter splanchnicus, Oribacterium sinus, Streptococcus gordonii, and Streptococcus parasanguinis) showed significantly positive correlations with PSQI scores ( r=0.476, 0.475, 0.369, 0.391, 0.401, 0.423) (all P<0.05), and they were mainly enriched in the glutamate and tryptophan synthesis pathways. Conclusions:The personalized IER diet intervention can improve the sleep of obese patients while reducing weight, possibly mediated by changes in gut microbiota through the glutamate and tryptophan pathways.