Effect of intermittent fasting, portfolio-moderate-carbohydrate, and anti-inflammatory diets on cardio-metabolic status in pre-diabetic patients; an open-label randomized clinical trial

Pre-diabetes is a condition characterized by hyperglycemia that does not meet the cutoff for the diagnosis of diabetes and increases the risk of non-communicable diseases. Choosing an appropriate diet is necessary to prevent the progression of pre-diabetes to diabetes. Therefore, the present study aimed to compare the effects of 3 diets, including intermittent fasting (IF) 5:2, portfolio-moderate-carbohydrate (PMC), and anti-inflammatory (AI) diets, compared to a healthy diet with carbohydrate distribution. This open label randomized clinical trial was performed on 98 patients with pre-diabetes that were randomly divided into four intervention groups, including IF 5:2 (n = 24), PMC (n = 24), AI (n = 25), and control group (n = 25). Adherence to these dietary intervention was assessed by dietary recall. Glycemic indices (fasting blood sugar (FBS) and hemoglobin A1c (HbA1c)), lipid profile, body composition, anthropometric indices (weight, waist circumference (WC), and body mass index (BMI)), and hs-C reactive protein (CRP) were assessed before and after dietary intervention. Mixed model regression was used for statistical analysis. Compared to the control group, the AI diet significantly reduced weight (β: -1.02; 95% CI: -1.96, -0.07; P = 0.017), FBS (β: -6.42; 95% CI: -12.9, -0.06; P = 0.026), and HbA1c (β: -0.27; 95% CI: -0.55, -0.007; P = 0.028). IF 5:2 showed significant reductions in waist circumference, BMI, FBS, and HbA1c, while PMC intervention resulted in significant improvements in FBS and HbA1c compared to the control group. The study demonstrated that AI, IF 5:2, and PMC diets improved glycemic control and anthropometric indices in pre-diabetic patients, with the AI diet showing the greatest beneficial effects. These findings suggest that anti-inflammatory dietary approaches may be an effective strategy for pre-diabetes management. Level I, randomized clinical trial. Registration number IRCT20200608047697N2, data 2024-05-16, https://irct.behdasht.gov.ir/trial/76653 .