Diet X Genotype Study

This study is ongoing, but not recruiting participants.
Sponsor:
Collaborator:
Nutrition Science Initiative
Information provided by (Responsible Party):
Christopher Gardner, Stanford University
ClinicalTrials.gov Identifier:
NCT01826591
First received: March 27, 2013
Last updated: October 1, 2015
Last verified: October 2015
  Purpose
Genomics research is advancing rapidly, and links between genes and obesity continue to be discovered and better defined. A growing number of single nucleotide polymorphisms (SNPs) in multiple genes have been shown to alter an individual's response to dietary macronutrient composition. Based on prior genetic studies evaluating the body's physiological responses to dietary carbohydrates or fats, the investigators identified multi-locus genotype patterns with SNPs from three genes (FABP2, PPARG, and ADRB2): a low carbohydrate-responsive genotype (LCG) and a low fat-responsive genotype (LFG). In a preliminary, retrospective study (using the A TO Z weight loss study data), the investigators observed a 3-fold difference in 12-month weight loss for initially overweight women who were determined to have been appropriately matched vs. mismatched to a low carbohydrate (Low Carb) or low fat (Low Fat) diet based on their multi-locus genotype pattern. The primary objective of this study is to confirm and expand on the preliminary results and determine if weight loss success can be increased if the dietary approach (Low Carb vs. Low Fat) is appropriately matched to an individual' s genetic predisposition (Low Carb Genotype vs. Low Fat Genotype) toward those diets.

Condition Intervention
Obesity
Insulin Resistance
Behavioral: Low-Carbohydrate Diet
Behavioral: Low-Fat Diet
Behavioral: Mobile App

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Do Genotype Patterns Predict Weight Loss Success for Low Carb vs. Low Fat Diets?

Further study details as provided by Stanford University:

Primary Outcome Measures:
  • Change from baseline in weight at 12 months [ Time Frame: Baseline, 3 months, 6 months, 12 months ] [ Designated as safety issue: No ]
    1. Diet Group X Genotype interaction, and 2. Diet Group by Baseline Insulin Resistance Status interaction


Secondary Outcome Measures:
  • Change in insulin resistance as assessed by Oral Glucose Tolerance Test [ Time Frame: Baseline, 6 months, 12 months ] [ Designated as safety issue: No ]
  • Change from baseline in lipids at 12 months [ Time Frame: Baseline, 3 months, 6 months, 12 months ] [ Designated as safety issue: No ]
    Total Cholesterol LDL Cholesterol HDL Cholesterol Triglycerides

  • Genotype (low-fat or low-carb) [ Time Frame: Baseline ] [ Designated as safety issue: No ]
  • Change from baseline in energy expenditure at 12 months [ Time Frame: Baseline, 6 months, 12 months ] [ Designated as safety issue: No ]
  • Change in percent body fat between baseline and 12 months [ Time Frame: Baseline, 6 months, 12 months ] [ Designated as safety issue: No ]
    As measured via DEXA scan

  • Change in various phsychosocial measures between baseline and 12 months [ Time Frame: Baseline, 3 months, 6 months, 12 months ] [ Designated as safety issue: No ]
    As measured via a battery of physchosocial questionnaires

  • Change in nutrient and food group intake between baseline and 12 months [ Time Frame: Baseline, 3 months, 6 months, 12 months ] [ Designated as safety issue: No ]
    As measured via NDSR Dietary Recalls

  • Change in vegetable consumption (Primary, Mobile App Sub-Study) [ Time Frame: 4-5 months, 6-7 months ] [ Designated as safety issue: No ]
    Vegetable consumption as measured by adapted Harvard food frequency questionnaire and 24-hr diet recalls (using NDSR-Nutrition Data System for Research). Primary outcome (mobile app sub-study): all vegetables. Secondary outcomes (mobile app sub-study): green leafy vegetables, dark and yellow vegetables, cruciferous vegetables, tomatoes, other vegetables, vegetable variety, vegetable liking.

  • Change from 3 months in weight at 6 months (Secondary, Mobile App Sub-Study) [ Time Frame: 3 months, 6 months ] [ Designated as safety issue: No ]
  • Change from 3 months in lipids at 6 months (Secondary, Mobile App Sub-Study) [ Time Frame: 3 months, 6 months ] [ Designated as safety issue: No ]
    Total Cholesterol

  • Change from 3 months in glucose at 6 months (Secondary, Mobile App Sub-Study) [ Time Frame: 3 months, 6 months ] [ Designated as safety issue: No ]
  • Change from 3 months in fasting insulin at 6 months (Secondary, Mobile App Sub-Study) [ Time Frame: 3 months, 6 months ] [ Designated as safety issue: No ]

Enrollment: 609
Study Start Date: March 2013
Estimated Study Completion Date: June 2016
Estimated Primary Completion Date: June 2016 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Experimental: Low-Carbohydrate Diet
Healthy, Low-Carbohydrate Diet
Behavioral: Low-Carbohydrate Diet
Counseling/instruction on how to follow a low-carbohydrate diet.
Behavioral: Mobile App
Mobile app to increase vegetable consumption. Participants with iPhones will be re-randomized to receive a mobile app beginning at either months 4-5 or months 7-8. The first phase during months 4-7 will be used to compare the effect of a mobile app (intervention) vs. no mobile app (waiting-list control). The a priori hypothesis is that vegetable consumption will increase among those who receive the app in both diet groups.
Experimental: Experimental: Low-Fat Diet
Healthy, Low-Fat Diet
Behavioral: Low-Fat Diet
Counseling/instruction on how to follow a low-fat diet.
Behavioral: Mobile App
Mobile app to increase vegetable consumption. Participants with iPhones will be re-randomized to receive a mobile app beginning at either months 4-5 or months 7-8. The first phase during months 4-7 will be used to compare the effect of a mobile app (intervention) vs. no mobile app (waiting-list control). The a priori hypothesis is that vegetable consumption will increase among those who receive the app in both diet groups.

Detailed Description:

If the intriguing preliminary retrospective results are confirmed in this full scale study, the results will demonstrate that inexpensive DNA testing could help dieters predict whether they will have greater weight loss success on a Low Carb or a Low Fat diet. Commensurate with increasing scientific interest in personalized medicine approaches to intervention development, this would provide an example of the potentially substantial health impacts that could be obtained through understanding specific gene-environment interactions that have been anticipated from the unraveling of the human genome.

Mobile App Sub-Study—For the purpose of augmenting adherence to high vegetable consumption in both diet groups, we will develop a theory-based mobile app to increase vegetable consumption through goal-setting, self-monitoring, and social comparison. Participants from both diet groups with iPhones will be re-randomized to receive the app at either months 4-5 or months 7-8. The first phase during months 4-7 will be used to compare the effect of a mobile app (intervention) vs. no mobile app (waiting-list control). The a priori hypothesis is that vegetable consumption will increase among those who receive the app in both diet arms. The investigator and outcomes assessor will be blinded to group assignment. Intention-to-treat analysis will be used.

  Eligibility

Ages Eligible for Study:   18 Years to 50 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Age: > 18 years of age
  • Women: Pre-menopausal (self-report) and <50 years of age
  • Men: <50 years of age
  • BMI (body mass index): 27-40 kg/m2 (need to lose >10% body weight to achieve healthy BMI)
  • Body weight stable for the last two months, and not actively on a weight loss plan
  • No plans to move from the area over the next two years
  • Available and able to participate in the evaluations and intervention for the study period
  • Willing to accept random assignment
  • To enhance study generalizability, people on medications not noted below as specific exclusions can
  • participate if they have been stable on such medications for at least three months
  • Ability and willingness to give written informed
  • No known active psychiatric illness

Exclusion Criteria:

Subjects with the following conditions will be excluded (determined by self-report):

  • Pregnant, lactating, within 6 months post-partum, or planning to become pregnant in the next 2 years
  • Diabetes (type 1 and 2) or history of gestational diabetes or on hypoglycemic medications for any other indication
  • Prevalent diseases: Malabsorption, renal or liver disease, active neoplasms, recent myocardial infarction (<6 months)(patient self-report and, if available, review of labs from primary care provider)
  • Smokers (because of effect on weight and lipids)
  • History of serious arrhythmias, or cerebrovascular disease
  • Uncontrolled hyper- or hypothyroidism (TSH not within normal limits)
  • Medications: Lipid lowering, antihypertensive medications, and those known to affect weight/energy expenditure
  • Excessive alcohol intake (self-reported, >3 drinks/day)
  • Musculoskeletal disorders precluding regular physical activity
  • Unable to follow either of the two study diets for reasons of food allergies or other (e.g., vegan)
  • Currently under psychiatric care, or taking psychiatric medications
  • Inability to communicate effectively with study personnel
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01826591

Locations
United States, California
Stanford University School of Medicine
Stanford, California, United States, 94305
Sponsors and Collaborators
Stanford University
Nutrition Science Initiative
Investigators
Principal Investigator: Christopher D Gardner, PhD Stanford University
  More Information

Additional Information:
No publications provided

Responsible Party: Christopher Gardner, Professor of Medicine, Stanford University
ClinicalTrials.gov Identifier: NCT01826591     History of Changes
Other Study ID Numbers: 22305 
Study First Received: March 27, 2013
Last Updated: October 1, 2015
Health Authority: United States: Institutional Review Board

Additional relevant MeSH terms:
Insulin Resistance
Glucose Metabolism Disorders
Hyperinsulinism
Metabolic Diseases

ClinicalTrials.gov processed this record on February 09, 2016