A Novel Diet-Phenotype Interaction Affecting Body Weight (FRESH Start)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01303757
Recruitment Status : Completed
First Posted : February 25, 2011
Last Update Posted : February 9, 2016
University of North Carolina, Chapel Hill
Broad Institute
Information provided by (Responsible Party):
David S. Ludwig, MD, PhD, Boston Children’s Hospital

February 22, 2011
February 25, 2011
February 9, 2016
February 2011
December 2015   (Final data collection date for primary outcome measure)
Percent body fat by dual-energy x-ray absorptiometry (DXA) [ Time Frame: 18 months ]
Same as current
Complete list of historical versions of study NCT01303757 on Archive Site
  • Triglyceride [ Time Frame: 18 months ]
  • HDL cholesterol [ Time Frame: 18 months ]
  • LDL cholesterol [ Time Frame: 18 months ]
  • C-reactive protein [ Time Frame: 18 months ]
  • Plasminogen Activator Inhibitor-1 [ Time Frame: 18 months ]
  • Fasting blood glucose [ Time Frame: 18 months ]
  • Insulin resistance [ Time Frame: 18 months ]
  • Blood pressure [ Time Frame: 18 months ]
  • Trunk fat [ Time Frame: 18 months ]
  • Metabolic Syndrome Components [ Time Frame: 18 months ]
  • Additional CVD risk [ Time Frame: 18 months ]
    LDL cholesterol
  • Effect modifiers [ Time Frame: baseline ]
    • Serum insulin concentration at 30 minutes following a standard 75-gram oral glucose load
    • Metabolomic profiles
    • Molecular identity of key metabolites
    • Insulin sensitivity
    • Abdominal-to-total fat ratio
    • Waist-to-hip ratio
  • Serum insulin concentration 30 minutes following a standard 75-gram oral glucose load [ Time Frame: 18 months ]
    Effect modification
  • Metabolomic profile [ Time Frame: 18 months ]
    Effect modification
  • Insulin sensitivity [ Time Frame: 18 months ]
    Effect modification
  • Abdominal-to-total fat ratio [ Time Frame: 18 months ]
    Effect modification
  • Waist-to-hip ratio [ Time Frame: 18 months ]
    Effect modification
Not Provided
A Novel Diet-Phenotype Interaction Affecting Body Weight
A Novel Diet-Phenotype Interaction Affecting Body Weight
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.
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.
Not Applicable
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Treatment
  • Obesity
  • Metabolic Syndrome
Behavioral: Dietary counselling
  • Experimental: Low glycemic load diet
    Low glycemic load diet
    Intervention: Behavioral: Dietary counselling
  • Active Comparator: Low fat diet
    Low fat diet
    Intervention: Behavioral: Dietary counselling
Not Provided

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
December 2015
December 2015   (Final data collection date for primary outcome measure)

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.
Sexes Eligible for Study: All
18 Years to 40 Years   (Adult)
Contact information is only displayed when the study is recruiting subjects
United States
Not Provided
Not Provided
David S. Ludwig, MD, PhD, Boston Children’s Hospital
Boston Children’s Hospital
  • University of North Carolina, Chapel Hill
  • Broad Institute
Study Director: Cara B Ebbeling, PhD Boston Children’s Hospital
Principal Investigator: David S Ludwig, MD, PhD Boston Children’s Hospital
Study Director: Leslie Fischer, PhD UNC Chapel Hill
Boston Children’s Hospital
February 2016

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP