The WORLD (Weight Optimization: Revamping Lifestyles Using the Dietary Guidelines) Study - Developing, Implementing, and Testing an Education Program

This study has been completed.
USDA Beltsville Human Nutrition Research Center
Information provided by (Responsible Party):
Penny Kris-Etherton, Penn State University Identifier:
First received: February 18, 2009
Last updated: November 30, 2011
Last verified: November 2011

The WORLD study is a single-center, year-long randomized controlled trial in free-living women. Participants were randomly assigned to follow either a lower-fat (LF) diet or a moderate-fat (MF) diet for weight management in a parallel-arm design. The two phases of the study were a weight-loss phase (phase 1) and a weight-maintenance phase (phase 2) (Figure 1). During phase 1, months 1 through 4, participants consumed a hypo-caloric diet consistent with the 2005 Dietary Guidelines in the free-living environment. During phase 2, months 5 through 12, participants shifted into weight maintenance. It was hypothesized that a weight-loss intervention at the extremes of dietary fat recommendations of the 2005 Dietary Guidelines would be equally effective for weight loss while achieving comparable nutrient adequacy. Also, Overall, the lower-fat and moderate-fat diets would both be nutritionally adequate, based on the Healthy Eating Index.

Condition Intervention
Cardiovascular Disease
Behavioral: Moderate-fat
Behavioral: Lower-fat

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Prevention
Official Title: Development, Implementation, & Testing and Education Program to Teach Weight Loss Using the 2005 Dietary Guidelines to Pre-Menopausal Women

Resource links provided by NLM:

Further study details as provided by Penn State University:

Primary Outcome Measures:
  • Body weight [ Time Frame: Baseline, month 4, month 8, month 12 ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Lipid Profile [ Time Frame: Baseline, month 4, month 8, month 12 ] [ Designated as safety issue: No ]
  • Glucose [ Time Frame: Baseline, month 4, month 8, month 12 ] [ Designated as safety issue: No ]
  • Insulin [ Time Frame: Baseline, month 4, month 8, month 12 ] [ Designated as safety issue: No ]
  • C-reactive protein [ Time Frame: Baseline, month 4, month 8, month 12 ] [ Designated as safety issue: No ]
  • Dietary intake [ Time Frame: Baseline, month 4, month 12 ] [ Designated as safety issue: No ]
  • Body composition [ Time Frame: Baseline, month 4, month 12 ] [ Designated as safety issue: No ]
  • Fitness via VO2max [ Time Frame: Baseline, month 4, month 12 ] [ Designated as safety issue: No ]
  • Cognitive-behavioral measures [ Time Frame: Baseline, month 4, month 8, month 12 ] [ Designated as safety issue: No ]

Enrollment: 101
Study Start Date: March 2006
Study Completion Date: December 2010
Primary Completion Date: June 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Moderate-fat
35% of calories from fat
Behavioral: Moderate-fat
35% of calories from fat
Experimental: Lower-fat
20% of calories from fat
Behavioral: Lower-fat
20% of calories from fat


Ages Eligible for Study:   21 Years to 50 Years
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • 21-50 years
  • BMI: 25-39.9 kg/m2
  • LDL-C: 100-189.9 mg/dL

Exclusion Criteria:

  • Triglycerides > 350 mg/dL
  • History of myocardial infarction, stroke, diabetes mellitus, liver disease, kidney disease, and thyroid disease
  • High alcohol consumption (<14 drinks/week)
  • Use of medication or supplements for lowering blood lipid levels (i.e., statin, fibrates, psyllium, fish oil capsules, soy lecithin, phytoestrogens)
  • Lactating, pregnant, or wanting to become pregnant during the study
  • Weight loss or gain ≥ 10% body weight in the previous 6 months
  • Eating Attitudes Test-26 score > 20
  • Beck Depression Inventory-II score ≥ 29
  • Gormally Cognitive Factors Related to Binge Eating Scale score > 30
  • Physical Activity Readiness Questionnaire score > 2
  Contacts and Locations
Please refer to this study by its identifier: NCT00847574

United States, Pennsylvania
Penn State University
University Park, Pennsylvania, United States, 16802
Sponsors and Collaborators
Penn State University
USDA Beltsville Human Nutrition Research Center
Principal Investigator: Penny M Kris-Etherton, PhD, RD Penn State University
  More Information

Additional Information:
No publications provided

Responsible Party: Penny Kris-Etherton, Distinguished Professor of Nutrition, Penn State University Identifier: NCT00847574     History of Changes
Other Study ID Numbers: WORLD Study, USDA CSREES #2005-55215-04811
Study First Received: February 18, 2009
Last Updated: November 30, 2011
Health Authority: United States: Institutional Review Board

Keywords provided by Penn State University:
Weight loss
Weight maintenance
Weight management
Cardiovascular disease risk
Dietary Guidelines
Diet and exercise

Additional relevant MeSH terms:
Cardiovascular Diseases
Nutrition Disorders
Body Weight
Signs and Symptoms processed this record on April 17, 2014