The Effects of Intermittent Fasting on Anthropometric Measurements and Metabolic Parameters in Prediabetic Patients

The goal of this randomized controlled trial is to learn about the short-term effects of an 8-hour time-restricted eating (TRE) protocol combined with caloric restriction in women aged 18-55 years with prediabetes. The main question it aims to answer is: Does an 8-hour time-restricted eating protocol combined with caloric restriction improve anthropometric measurements and metabolic parameters more than caloric restriction alone in women with prediabetes? Researchers will compare the time-restricted eating (IF) group to a control group following a conventional calorie-restricted diet with no time restriction, to see whether time-restricted eating provides additional benefit beyond that of caloric deficit alone. Participants will: Be randomly assigned to either the IF group (all meals consumed within an 8-hour window, 16-hour daily fast) or the control group (calorie-restricted diet, no time restriction), both matched for a 500 kcal/day energy deficit Follow their assigned diet for 5 weeks, with daily dietary reminders and support Undergo assessments at baseline and at the end of the 5-week intervention, including body weight, BMI, waist/hip circumference, body composition (bioimpedance), and fasting blood tests (glucose, insulin, HbA1c, total cholesterol, HDL-C, LDL-C, triglycerides)

Inclusion Criteria: * Female sex * Age between 18 and 55 years * Diagnosis of prediabetes (fasting plasma glucose 100-125 mg/dL and/or HbA1c 5.7%-6.4%) * Willingness and ability to attend in-person dietitian counseling at the Family Health Center Unit and to use WhatsApp for daily follow-up and reporting Provision of written informed consent Exclusion Criteria: * Pregnancy or lactation * Use of antidiabetic or immunosuppressive medications * Presence of endocrine disorders * History of malignancy or organ transplantation * Prior bariatric surgery