AzTrials
AzTrials

ObesityPhase 2NCT00079573

Comparison of Popular Weight Loss Diets

A Phase 2 study testing Atkins diet (extremely low carbohydrate), Zone diet (low carbohydrate, high protein) and Ornish diet (very low fat) in people with Obesity, run by National Center for Complementary and Integrative Health (NCCIH) at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial 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. Read more about this study

Who is it for?
Ages 30 to 50 years, women onlyHealthy volunteers can take part
Conditions the study is for
Obesity
What is being tested?
Atkins diet (extremely low carbohydrate), Zone diet (low carbohydrate, high protein) and Ornish diet (very low fat)
How many people
300 participants
Where
1 siteUnited States
Study dates
Jul 2002to Jun 2004
Phase
Phase 2
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 30 to 50 years
  • Women only
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • 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

Who cannot join

  • 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
Show all 9Show fewer
  • Excessive alcohol intake (self-reported, > 3 drinks/day)
  • Postmenopausal, including surgical menopause
  • Currently under psychiatric care or severely clinically depressed (> 17 on Beck Inventory)

Trial locations and contacts

1 site in 1 country.

United States1 site
  • Stanford Prevention Research Center

    Stanford, California, 94305

Other trials in United States

About this study

Official title: 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.

Read the 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.

Conditions
Obesity
Being tested
Atkins diet (extremely low carbohydrate), Zone diet (low carbohydrate, high protein), Ornish diet (very low fat)
Keywords
Weight Loss, Obesity, Overweight, Premenopausal women, Diet
Medical subject headings
Obesity, Weight Loss, Overweight

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Atkins diet (extremely low carbohydrate)Behavioural

  • Zone diet (low carbohydrate, high protein)Behavioural

  • Ornish diet (very low fat)Behavioural

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Weight; measured at each study visit

  2. Percent body fat; measured at each study visit

Secondary outcomes (3)
  1. Blood lipids (cholesterol, triglycerides); measured at each study visit

  2. Fasting insulin and glucose; measured at each study visit

  3. Behavioral variables; measured at each study visit

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted10 Mar 2004 (estimated)
  2. Study startJul 2002
  3. Study completionJun 2004

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Single blind
Enrolment
300 participants
IDs, dates and publications
ClinicalTrials.gov ID
NCT00079573
Sponsor's protocol ID
R21AT001098-01A1
Status last verified
Aug 2006
First submitted
9 Mar 2004
Last updated
18 Aug 2006
Results posted
No

Publications

  • Gardner CD, Kiazand A, Alhassan S, Kim S, Stafford RS, Balise RR, Kraemer HC, King AC. Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial. JAMA. 2007 Mar 7;297(9):969-77. doi: 10.1001/jama.297.9.969.

    PubMed 17341711

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Atkins diet (extremely low carbohydrate), Zone diet (low carbohydrate, high protein) and Ornish diet (very low fat) in people with Obesity, run by National Center for Complementary and Integrative Health (NCCIH) at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 5 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 18 Aug 2006. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Weight; measured at each study visit. The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT00079573, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Aug 2006.

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