Comparison of Popular Weight Loss Diets

August 16, 2006 updated by: National Center for Complementary and Integrative Health (NCCIH)

Benefits & Risks of Popular Weight Loss Diets

This study will compare the safety and effectiveness of three popular weight loss plans. These plans will be compared with the USDA Dietary Guidelines.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Obesity is the single most significant, nutrition-related health issue of the new millennium. Several "medical experts" have designed and promoted weight loss diets that dramatically differ from one another and from the USDA Dietary Guidelines. These diets have gained surprisingly widespread and persistent popularity among Americans despite the lack of evidence supporting their claims. This clinical trial will provide preliminary feasibility data for a full-scale study that will examine health outcomes (e.g., benefits, risks, success) of three popular weight loss diets. The study will investigate behavioral and physiological factors that influence adherence and retention to these diet plans.

Overweight women will be randomly assigned to one of four diets for 1 year: Atkins (extremely low carbohydrate), Zone (low carbohydrate, high protein), Ornish (very low fat), or USDA/Food Pyramid (high carbohydrate/moderate-low fat). Behavioral and physiological data will be collected. Participants attend study visits at baseline, 8 weeks, 6 months, and 1 year. At these visits, measurements will include that will include weight and blood pressure measurements and blood tests. Participants will be asked to complete ten questionnaires over the course of the study to assess behavior and appetite. Participants will also undergo a DEXA scan to assess body composition.

Study Type

Interventional

Enrollment

300

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Stanford, California, United States, 94305
        • Stanford Prevention Research Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

30 years to 50 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Description

Inclusion Criteria

  • Body mass index (BMI) between 27 and 40 kg/m2
  • Weight stable for last 2 months
  • Not actively on a weight loss plan
  • No plans to move from the area over the next 2 years
  • Willing to accept random assignment

Exclusion Criteria

  • Pregnant or breastfeeding
  • Within 6 months of giving birth or planning to become pregnant in the next 2 years
  • Diabetes (type 1 or 2) or history of gestational diabetes
  • Renal or liver disease, active neoplasms, or recent myocardial infarction
  • Hyper- or hypothyroidism
  • Lipid lowering medications or medications known to affect weight/energy expenditure
  • Excessive alcohol intake (self-reported, > 3 drinks/day)
  • Postmenopausal, including surgical menopause
  • Currently under psychiatric care or severely clinically depressed (> 17 on Beck Inventory)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Weight; measured at each study visit
Percent body fat; measured at each study visit

Secondary Outcome Measures

Outcome Measure
Blood lipids (cholesterol, triglycerides); measured at each study visit
Fasting insulin and glucose; measured at each study visit
Behavioral variables; measured at each study visit

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Center for Complementary and Integrative Health (NCCIH)

Collaborators

Community Foundation of Southeastern Michigan

Investigators

  • Principal Investigator: Christopher D. Gardner, PhD, Stanford University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 2002

Study Completion

June 1, 2004

Study Registration Dates

First Submitted

March 9, 2004

First Submitted That Met QC Criteria

March 9, 2004

First Posted (Estimate)

March 10, 2004

Study Record Updates

Last Update Posted (Estimate)

August 18, 2006

Last Update Submitted That Met QC Criteria

August 16, 2006

Last Verified

August 1, 2006

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • R21AT001098-01A1 (U.S. NIH Grant/Contract)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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