DIETFITS Study (Diet Intervention Examining the Factors Interacting With Treatment Success

Summary

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.

Conditions

• Obesity
• Insulin Resistance

Interventions

BEHAVIORAL

Low-Carbohydrate Diet

Counseling/instruction on how to follow a low-carbohydrate 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.

Sponsors & Collaborators

• Nutrition Science Initiative

  collaborator OTHER

• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

  collaborator NIH

• National Heart, Lung, and Blood Institute (NHLBI)

  collaborator NIH

• National Center for Advancing Translational Sciences (NCATS)

  collaborator NIH

• Stanford University

  lead OTHER

Principal Investigators

• Christopher D Gardner, PhD · Stanford University

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

50 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2013-01-31

Primary Completion

2016-05-31

Completion

2016-05-31

Countries

• United States

Study Locations