Basic Carbohydrate Counting in Prediabetes (CARB-PRED)

May 7, 2026 updated by: Hamide Sahin

The Effect of Basic Carbohydrate Counting on HbA1c in Prediabetes: A Randomized Controlled Trial

Type 2 diabetes mellitus (T2DM) is a major global health problem with rapidly increasing prevalence. Prediabetes represents a high-risk state for developing T2DM and is often asymptomatic, delaying diagnosis and intervention. Early identification and effective lifestyle interventions are essential to prevent or delay the progression to diabetes. Primary care settings provide an important opportunity for screening and implementing preventive strategies.

Lifestyle modification, including dietary changes and physical activity, is the cornerstone of diabetes prevention. Carbohydrate counting is a medical nutrition therapy widely used in diabetes management and has been shown to improve glycemic control. However, there is limited evidence regarding its effectiveness in individuals with prediabetes.

This study aims to evaluate the effect of basic carbohydrate counting education on HbA1c levels in individuals with prediabetes in a primary care setting.

This randomized controlled trial will be conducted in the Family Medicine outpatient clinic of Marmara University Hospital. Individuals aged 18 years and older with HbA1c levels between 5.7% and 6.4% will be included. Participants will be randomized into intervention and control groups in a 2:1 ratio.

The control group will receive standard lifestyle recommendations, while the intervention group will receive additional structured basic carbohydrate counting education in three sessions. HbA1c levels will be measured at baseline,at third and at 6 months. Secondary outcomes include body weight, body mass index, waist circumference,lipid panel and carbohydarte counting knowledge scale The findings of this study are expected to contribute to the development of effective, scalable, and practical nutritional interventions for diabetes prevention in primary care

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Type 2 diabetes mellitus (T2DM) is a major and rapidly growing global health problem. Prediabetes represents a high-risk state for progression to T2DM and provides a critical window for preventive interventions. Since prediabetes is often asymptomatic, early detection and effective lifestyle-based strategies are essential. Primary care settings offer an optimal environment for identifying high-risk individuals and implementing preventive interventions.

Lifestyle modification, particularly dietary interventions and physical activity, is the cornerstone of diabetes prevention. Medical nutrition therapy (MNT) has been shown to play a key role in improving glycemic outcomes. Basic carbohydrate counting (CC), as a component of MNT, is a practical and structured dietary approach aimed at increasing awareness of carbohydrate intake and improving glycemic control. However, evidence regarding its effectiveness in individuals with prediabetes remains limited.

This study aims to evaluate the effect of basic carbohydrate counting education on HbA1c levels in individuals with prediabetes in a primary care setting.

This study will be designed as a randomized controlled trial conducted at the Family Medicine outpatient clinic of Marmara University Hospital. Adults aged 18 years and older with HbA1c levels between 5.7% and 6.4% who meet the inclusion criteria and provide informed consent will be enrolled.

Participants will be randomized into intervention and control groups using a simple randomization method in a 2:1 ratio. All participants will receive standard lifestyle recommendations as part of usual care. Additionally, a booklet including information on healthy nutrition and basic carbohydrate counting, prepared based on current scientific literature, will be provided to all participants.

At baseline, all participants will complete a questionnaire assessing sociodemographic characteristics and diabetes-related factors. The "Nutrition and Basic Carbohydrate Counting Knowledge Scale" will be administered at baseline, 3 months, and 6 months. This scale consists of 20 items, including true/false statements and two fill-in-the-blank questions related to fasting and postprandial blood glucose.

Anthropometric measurements including body weight, body mass index (BMI), and waist circumference (WC) will be recorded at baseline, 3 months, and 6 months. Laboratory assessments including HbA1c, fasting blood glucose (FBG), and lipid profile will also be performed at the same time points.

Participants in the intervention group will receive structured basic carbohydrate counting education delivered in three sessions at one-week intervals, each lasting 30-45 minutes. The training program will be developed in collaboration with a dietitian. Participants in the intervention group will also be asked to complete 3-day dietary records before each training session.

Following the training sessions, participants in the intervention group will be followed up with monthly telephone calls. During these follow-ups, adherence to the intervention will be evaluated, and participants' questions will be addressed.

The primary outcome of the study will be the change in HbA1c levels from baseline to 6 months. Secondary outcomes will include changes in body weight, BMI, waist circumference, lipid profile, and carbohydrate counting knowledge level.

This study is expected to provide evidence on the effectiveness of a practical and applicable dietary intervention in preventing the progression from prediabetes to T2DM in primary care settings.

Study Type

Interventional

Enrollment (Estimated)

120

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adults aged 18 years and older
  • Able to read and write Individuals with prediabetes who are not using or are unwilling to initiate oral antidiabetic drugs.

Exclusion Criteria:

  • Individuals with a diagnosis of diabetes mellitus
  • Those who have previously received carbohydrate counting training or are currently applying carbohydrate counting
  • Individuals with low daily carbohydrate intake (<100 g/day)
  • Presence of uncontrolled medical conditions that may affect dietary intake, as determined by the investigator
  • Pregnant or breastfeeding women, or those planning pregnancy during the study period
  • Participation in another clinical study Inability or unwillingness to provide informed consent or comply with study procedures
  • Cognitive impairment or communication difficulties (hearing, understanding, or speaking)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Standard Care (No Structured Nutrition Education)
Participants in the control group will receive standard care without structured carbohydrate counting-based nutrition education.
Behavioral: Standard Care (No Structured Nutrition Education)
Participants in the control group will receive standard care without structured carbohydrate counting-based nutrition education.
Experimental: Carbohydrate Counting-Based Nutrition Education
Participants receive structured nutrition education based on carbohydrate counting, including dietary counseling and follow-up during the study period.
Behavioral: Carbohydrate Couinting-Based Nutrition Education
Participants assigned to the intervention group will receive a structured nutrition education program based on carbohydrate counting principles. The program will be delivered by a physician and will cover carbohydrate identification, portion estimation, meal planning, and practical application in daily dietary habits. The aim of the intervention is to improve glycemic control by increasing nutritional knowledge and promoting behavioral changes. Outcome measures will be evaluated at baseline, 3 months, and 6 months.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The change in HbA1c level
Time Frame: from baseline to 6 months
The change in HbA1c levels from baseline to 6 months will be assessed to evaluate the effect of carbohydrate counting-based nutrition education.
from baseline to 6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hamide Sahin

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 27, 2026

Primary Completion (Estimated)

July 1, 2026

Study Completion (Estimated)

November 1, 2026

Study Registration Dates

First Submitted

April 6, 2026

First Submitted That Met QC Criteria

April 6, 2026

First Posted (Actual)

April 13, 2026

Study Record Updates

Last Update Posted (Actual)

May 12, 2026

Last Update Submitted That Met QC Criteria

May 7, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Marmara Univ IRB 09.2026.605

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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