A Novel Diet-Phenotype Interaction Affecting Body Weight

NCT ID: NCT01303757

Last Updated: 2016-02-09

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 155 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2011-02-28
• Study Completion Date: 2015-12-31

Brief Summary

The primary aim of the study is to examine insulin secretion as an effect modifier of the efficacy of a low-fat vs. low-glycemic load diet for weight loss among overweight/obese young adults in an 18-month, prospectively stratified, multi-center randomized controlled trial.

Detailed Description

In recent years, diets of widely varying composition have been used in the treatment of obesity. While none of these diets has produced consistent, long-term weight loss, some individuals on virtually all types of diets do remarkably well. One explanation for this variation among individuals is differences in motivation and behavior. However, underlying biological differences may also play an important role. Previous work has identified insulin secretion (as quantified by serum insulin concentration at 30 minutes following a standard 75-gram oral glucose load) as an important biological determinant. This randomized-controlled, multi-center trial aims to test the hypothesis that insulin secretion will predict which type of diet will work best for each individual. A total of 160 obese young adults (18 to 40 years) will be assigned to one of two diets: low-fat (60% carbohydrate, 20% fat, 20% protein) or low-glycemic load (45% carbohydrate, 35% fat, 20% protein). Participants will be enrolled at two sites (Children's Hospital Boston or University of North Carolina-Chapel Hill) and assigned to diet groups according to baseline insulin secretion status. The protocol will include an intensive 6-month intervention period and a 12-month follow-up period. Registered dietitians will provide nutrition education and behavioral counseling during group workshops and scheduled telephone calls. In an effort to avoid confounding, close attention will be paid to control for treatment intensity, physical activity prescriptions, and behavioral methods between groups. The primary endpoint will be percent body fat by DXA scan. Secondary endpoints will include cardiovascular and diabetes risk factors. Repeated, 24-hour dietary and physical activity recall interviews will provide process data. Metabolomic profiling and molecular analysis of identified metabolites will be conducted to characterize phenotype and explore potential physiological mechanisms. A successful outcome of this work will inform the practice of "personalized" nutritional therapy, enhancing the ability to select the most efficacious weight loss diet for an individual based on underlying biological differences.

Conditions

Obesity; Metabolic Syndrome

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

Low glycemic load diet

Low glycemic load diet

Group Type: EXPERIMENTAL

Dietary counselling

Intervention Type: BEHAVIORAL

Low fat diet

Low fat diet

Group Type: ACTIVE_COMPARATOR

Dietary counselling

Intervention Type: BEHAVIORAL

Interventions

Dietary counselling

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

• Aged 18 to 40 years.
• Body mass index (BMI) ≥ 27 kg/m2.
• Body weight ≤ 300 lb.
• Access to a working telephone.
• Clearance in writing from a primary care provider (i.e., physician or nurse practitioner) to rule out pre-existing medical conditions.
• Willing and able to attend group workshops (for dietary intervention) on specified evenings.

Exclusion Criteria

• Physician diagnosis of a major medical illness or eating disorder.
• Chronic use of any medication that may affect study outcomes (e.g., insulin-sensitizing agents).
• Current smoking (i.e., 1 cigarette in the past week).
• Physical, mental, or cognitive handicaps that prevent participation.
• Another member of the family (i.e., first degree relative) or household participating in the study.
• Planning to relocate from current area of residence during the proposed timeframe for study participation.
• If female, planning to become pregnant during the 18 months of the study.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 40 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of North Carolina, Chapel Hill

OTHER

Sponsor Role: collaborator

Broad Institute of MIT and Harvard

OTHER

Sponsor Role: collaborator

Boston Children's Hospital

OTHER

Sponsor Role: lead

Responsible Party

David S. Ludwig, MD, PhD

Director, Obesity Prevention Center

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Cara B Ebbeling, PhD

Role: STUDY_DIRECTOR

Boston Children's Hospital

David S Ludwig, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

Boston Children's Hospital

Leslie Fischer, PhD

Role: STUDY_DIRECTOR

UNC Chapel Hill

Locations

Children's Hospital Boston

Boston, Massachusetts, United States

University of North Carolina, Chapel Hill

Chapel Hill, North Carolina, United States

Countries

United States

Other Identifiers

10-04-0156

Identifier Type: -

Identifier Source: org_study_id