Comparison of Popular Weight Loss Diets

Sponsor

National Center for Complementary and Integrative Health (NCCIH) (NIH)

Overall Status

Completed

CT.gov ID

NCT00079573

Collaborator

Community Foundation of Southeastern Michigan (Other)

300

Enrollment

Location

Duration (Months)

Patients Per Site Per Month

Study Details

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.

Condition or Disease	Intervention/Treatment	Phase
Obesity	Behavioral: Atkins diet (extremely low carbohydrate) Behavioral: Zone diet (low carbohydrate, high protein) Behavioral: Ornish diet (very low fat)	Phase 2

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 Design

Study Type:

Interventional

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Single

Primary Purpose:

Treatment

Official Title:

Benefits & Risks of Popular Weight Loss Diets

Study Start Date :

Jul 1, 2002

Study Completion Date :

Jun 1, 2004

Outcome Measures

Primary Outcome Measures

Weight; measured at each study visit []
Percent body fat; measured at each study visit []

Secondary Outcome Measures

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 []

Eligibility Criteria

Criteria

Ages Eligible for Study:

30 Years to 50 Years

Sexes Eligible for Study:

Female

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)