Impact of Timed Carbohydrate Restriction on Liver Fat Regression in Non-Diabetic Adults With Obesity

Abstract

Background: Hepatic steatosis is a common obesity-associated metabolic condition that may occur in non-diabetic adults and contribute to progressive hepatic and cardiometabolic risk. Dietary modification is central to management, but the effect of restricting carbohydrate intake to an earlier daily time window remains insufficiently defined. Objective: To evaluate whether timed carbohydrate restriction improves hepatic steatosis severity and metabolic indicators in non-diabetic adults with obesity. Methods: A parallel-group randomized controlled trial was conducted in Southern Punjab, Pakistan, from August 2025 to January 2026. Eighty non-diabetic adults aged 25–60 years with obesity and ultrasonography-confirmed hepatic steatosis were randomized to timed carbohydrate restriction or standard dietary advice. The intervention group consumed carbohydrate-containing foods only between 8:00 a.m. and 4:00 p.m. for 12 weeks, while the control group received conventional weight-management advice without carbohydrate-timing restriction. The primary outcome was change in ultrasound-graded hepatic steatosis severity. Secondary outcomes included body mass index, waist circumference, fasting insulin, HOMA-IR, and alanine aminotransferase. Results: Seventy-three participants completed follow-up assessment. Hepatic steatosis score decreased from 2.73 ± 0.61 to 1.38 ± 0.55 in the intervention group and from 2.69 ± 0.59 to 2.01 ± 0.63 in the control group. The between-group difference in mean change was -0.67, and the time-by-group interaction was significant (F=24.58, p<0.001). At 12 weeks, the intervention group also had lower BMI, waist circumference, fasting insulin, HOMA-IR, and alanine aminotransferase. Conclusion: Timed carbohydrate restriction was associated with greater 12-week improvement in hepatic steatosis and metabolic indicators among non-diabetic adults with obesity.