History of Changes for Study: NCT00079573
Comparison of Popular Weight Loss Diets
Latest version (submitted August 16, 2006) on
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Study Record Versions
Version A B Submitted Date Changes
1 June 23, 2005 None (earliest Version on record)
2 September 2, 2005 Study Status and Outcome Measures
3 September 6, 2005 Recruitment Status, Outcome Measures, Study Status and Study Description
4 July 25, 2006 Study Status and Oversight
5 August 2, 2006 Study Status, Study Design and Sponsor/Collaborators
6 August 16, 2006 Study Identification and Study Status
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Study NCT00079573
Submitted Date:  June 23, 2005 (v1)

Open or close this module Study Identification
Unique Protocol ID: 1R21AT001098-01A1
Brief Title: Comparison of Popular Weight Loss Diets
Official Title: Benefits & Risks of Popular Weight Loss Diets
Secondary IDs:
Open or close this module Study Status
Record Verification: October 2004
Overall Status: Active, not recruiting
Study Start: July 2002
Primary Completion:
Study Completion: June 2004
First Submitted: March 9, 2004
First Submitted that
Met QC Criteria:
March 9, 2004
First Posted: March 10, 2004 [Estimate]
Last Update Submitted that
Met QC Criteria:
June 23, 2005
Last Update Posted: June 24, 2005 [Estimate]
Open or close this module Sponsor/Collaborators
Sponsor: National Center for Complementary and Integrative Health (NCCIH)
Responsible Party:
Open or close this module Oversight
U.S. FDA-regulated Drug:
U.S. FDA-regulated Device:
Data Monitoring:
Open or close this module Study Description
Brief Summary: This study will compare the safety and effectiveness of three popular weight loss plans. These plans will be compared with the USDA Dietary Guidelines.
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 will have 4 study visits 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.

Open or close this module Conditions
Conditions: Obesity
Keywords: Weight Loss
Premenopausal women
Open or close this module Study Design
Study Type: Interventional
Primary Purpose: Treatment
Study Phase: Phase 2
Interventional Study Model: Parallel Assignment
Number of Arms:
Masking: Single (masked role unspecified)
Allocation: Randomized
Enrollment: 48
Open or close this module Arms and Interventions
Intervention Details:
Behavioral: Atkins diet (extremely low carbohydrate)
Behavioral: Zone diet (low carbohydrate, high protein)
Behavioral: Ornish diet (very low fat)
Open or close this module Outcome Measures
Open or close this module Eligibility
Minimum Age: 30 Years
Maximum Age: 50 Years
Sex: Female
Gender Based:
Accepts Healthy Volunteers: Yes

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)
Open or close this module Contacts/Locations
Study Officials: Christopher D. Gardner, PhD
Principal Investigator
Stanford University
Locations: United States, California
Stanford Prevention Research Center
Stanford, California, United States, 94305
Open or close this module IPDSharing
Plan to Share IPD:
Open or close this module References
Links: Description: Stanford Center for Research in Disease Prevention
Available IPD/Information:

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U.S. National Library of Medicine | U.S. National Institutes of Health | U.S. Department of Health & Human Services