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

NCT07713394 | Completed

• 1 other identifier: B.30.2.ATA.0.01.00/699
• Study Type: interventional
• Target: 36
• Locations: 1 country
• Sites: 1

Brief Summary

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)

Conditions

Prediabetes; Intermittent Fasting; Weight

Outcome Measures

Primary Outcomes (1)

• weight

  weight and height will be combined to report BMI in kg/m\^2

  5 weeks

Secondary Outcomes (2)

• Waist circumference (WC)

  5 weeks

• lipid parameters

  5 weeks

Study Arms (2)

Intermittent Fasting (IF)

EXPERIMENTAL

Participants in the IF group followed a time-restricted eating schedule, consuming all meals within an 8-hour window (10:00 AM-6:00 PM), with a fasting period of 16 hours daily. To facilitate adherence and minimize side effects, the fasting duration was gradually increased over the first 6 days (12 hours for Days 1-3, 14 hours for Days 4-6), then maintained at 16 hours for the remaining 4 weeks. Diets were customized to individual energy needs and divided into 2-3 meals during the feeding window. Participants received daily reminders and support via WhatsApp, and were encouraged to report their food intake and physical activity.

Behavioral: Intermittent fasting

Control Group (CG)

ACTIVE COMPARATOR

The CG participants followed a conventional hypocaloric diet with no time restriction. Their meals were distributed over 5-6 eating occasions throughout the day, spaced at 3-3.5 hour intervals. Diet content matched that of the IF group in terms of energy deficit and macronutrient composition. Participants received daily follow-up and education similar to the IF group.

Behavioral: Caloric restriction

Interventions

Intermittent fasting BEHAVIORAL

Eating in a specific hours of days, and being fast on remain of the day.

Intermittent Fasting (IF)

Caloric restriction BEHAVIORAL

The participants followed a conventional hypocaloric diet with no time restriction. Their meals were distributed over 5-6 eating occasions throughout the day, spaced at 3-3.5 hour intervals

Control Group (CG)

Eligibility Criteria

• Age: 18 Years - 55 Years
• Gender Eligibility Details: women
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• Pregnancy or lactation
• Use of antidiabetic or immunosuppressive medications
• Presence of endocrine disorders
• History of malignancy or organ transplantation
• Prior bariatric surgery

Sponsors & Collaborators

• Ataturk University: lead

Study Sites (1)

Ataturk University

Erzurum, Turkey, 25040, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Prediabetic State; Intermittent Fasting; Body Weight

Interventions

Caloric Restriction

Condition Hierarchy (Ancestors)

Diabetes Mellitus; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases; Fasting; Feeding Behavior; Behavior; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Diet Therapy; Nutrition Therapy; Therapeutics; Energy Intake; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Prof. Dr.

Study Record Dates

• First Submitted: July 10, 2026
• First Posted: July 20, 2026
• Study Start: January 1, 2023
• Primary Completion: December 31, 2023
• Study Completion: December 31, 2023
• Last Updated: July 20, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)