Purpose

The proposed randomized controlled trial will test the effect of a low-carbohydrate diet on hemoglobin A1c among individuals with elevated hemoglobin A1c that are within the range of prediabetes or diabetes. Results may provide evidence about the role of carbohydrate restriction in individuals with or at high risk of type 2 diabetes.

Conditions

Eligibility

Eligible Ages
Between 40 Years and 70 Years
Eligible Genders
All
Accepts Healthy Volunteers
Yes

Inclusion Criteria

  • Men or women ages 40 to 70 years
  • HbA1c 6.0-6.9%
  • Willing and able to provide informed consent

Exclusion Criteria

  • Diagnosed type 1 diabetes mellitus
  • Use of agents affecting glycemic control (medications for diabetes, oral glucocorticoids) within the past three months prior to enrollment
  • Medical condition in which low-carbohydrate diet may not be advised: estimated glomerular filtration rate (eGFR) ≤45 mL/min/1.73 m²; self-report of liver disease due to hepatitis or alcohol; osteoporosis; untreated thyroid disease; gout; cancer (other than non-melanoma skin cancer) requiring treatment in the past year, unless prognosis is excellent
  • Factors that may affect HbA1c: hemoglobin <11 mg/dL (cutpoint for moderate-to-severe anemia, which could lead to falsely elevated or lowered HbA1c); recent blood donation or blood transfusion (self-report, past 4 months); human immunodeficiency virus (self-report)
  • Self-reported history of intensive care unit stay due to Coronavirus Disease 2019 (COVID-19) in the past three months, as severe COVID-19 may affect blood glucose levels
  • Allergies to nuts
  • For women, current pregnancy, breastfeeding, or plans to become pregnant during the study
  • Consumption of ≥21 alcoholic drinks per week or consumption of ≥6 drinks per occasion
  • Current or planned residence making it difficult to meet trial requirements (due to distance from study site and/or challenges regularly traveling to site)
  • Current participation in another lifestyle intervention trial or a pharmaceutical trial
  • Participation of another household member in the study; employees or persons living with employees of the study
  • Other concerns regarding ability to meet trial requirements, at the discretion of the principal investigator or study coordinator

Study Design

Phase
N/A
Study Type
Interventional
Allocation
Randomized
Intervention Model
Parallel Assignment
Primary Purpose
Prevention
Masking
Double (Investigator, Outcomes Assessor)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Low-Carbohydrate Diet
Behavioral modification to reduce carbohydrate consumption. Target <40 g net carbohydrates per day for first 3 months; <60 g net carbohydrates per day for months 4 onwards. The intervention will consist of 4 weekly individual counseling sessions, followed by 4 group sessions held every other week, with phone follow-ups in between group sessions. For the last 3 months of the study, there will be 3 monthly group sessions and 3 telephone follow-ups. At baseline, participants will receive written information with standard physical activity recommendations.
  • Behavioral: Low-Carbohydrate Diet
    Behavioral modification to reduce carbohydrate consumption. Target <40 g net carbohydrates per day for first 3 months; <60 g net carbohydrates per day for months 4 onwards. The intervention will consist of 4 weekly individual counseling sessions, followed by 4 group sessions held every other week, with phone follow-ups in between group sessions. For the last 3 months of the study, there will be 3 monthly group sessions and 3 telephone follow-ups. At baseline, participants will receive written information with standard physical activity recommendations.
No Intervention
Usual Diet
No dietary intervention. At baseline, participants will receive written information with standard dietary advice and standard physical activity recommendations.

Recruiting Locations

Tulane Office of Health Research
New Orleans, Louisiana 70112
Contact:
Paige Pielet, BSPH
504-988-5225
ppielet@tulane.edu

More Details

Status
Recruiting
Sponsor
Tulane University School of Public Health and Tropical Medicine

Study Contact

Paige Pielet, BSPH
504-988-5225
ppielet@tulane.edu

Detailed Description

In the short-term, among patients with type 2 diabetes, low-to-moderate carbohydrate diets have a greater glucose-lowering effect than do high-carbohydrate diets. However, compared with usual diet, the effect of a behavioral intervention promoting a low-carbohydrate/high-unsaturated fat and high-protein dietary pattern among individuals with prediabetes or untreated type 2 diabetes is not well understood.

The overall goal of this randomized controlled trial is to study the effect of a behavioral intervention promoting a low-carbohydrate/high-unsaturated fat and high-protein dietary pattern compared with usual diet on hemoglobin A1c (HbA1c) and other metabolic risk factors among individuals with or at high risk of diabetes (HbA1c 6.0-6.9%).

A total of 150 participants with HbA1c 6.0-6.9% will be recruited and randomly assigned to either a 6-month behavioral modification program designed to reduce carbohydrate intake (initial target <40 g digestible carbohydrates, final target <60 g digestible carbohydrates) or to usual diet in a 1:1 randomization ratio.

The primary outcome will be the difference between the active intervention and control groups for change in HbA1c from baseline to 6 months. Secondary outcomes will be fasting glucose, systolic blood pressure, total-to-high-density lipoprotein-cholesterol ratio, and body weight.

Findings from this study may provide evidence about the role of carbohydrate restriction in individuals with or at high risk of type 2 diabetes.

Notice

Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.