Dietary Energy Restriction and Metabolic Aging in Humans

November 8, 2006 updated by: National Institute on Aging (NIA)
The purpose of this study is to develop an effective calorie restricted diet.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This study is a 3-phase investigation designed to test two caloric restriction (CR) regimens for participant compliance and variability in metabolic and physiologic effects. Initially, and through phase 1 (1 week pre-phase, and 6 weeks phase 1), participants will maintain normal habits at home.

Then for phase 2 (24 weeks), the 44 participants will be randomized to one of two diets (Diet HG or Diet LG), which they will consume at either 70% or 90% of baseline energy intake. The participants randomized to 90% CR (both diets) will form the control group. All food will be provided during this phase, and participants will be required to attend weekly group or individual meetings with the behavioral counselor and dietitian, and perform regular self-monitoring.

During phase 3 (24 weeks), participants will prepare their own food at home according to their CR regimen and will eat to maintain the CR specified for phase 2. They will continue to attend the weekly meetings and to perform self-monitoring.

Diet HG: a diet based on the USDA Food Guide Pyramid, but with additional emphasis on adequate fiber and low energy density foods, including use of whole grains rather than refined carbohydrates, limited liquid calories, high variety of low energy items such as fruits and vegetables and low variety of high-energy discretionary foods.

Diet LG: a modification of the HG diet in which low energy density is maintained even though the percent of energy from fat and protein is increased (by increased use of high-protein foods and foods with high water content) and use of different carbohydrate sources and physically intact food items (whole grains, raw fruits and vegetables) to further lower glycemic load through reducing the glycemic index (GI). High fiber intakes, low energy density, limited use of liquid calories, high variety of low energy items such as fruits and vegetables and low variety of high-energy discretionary foods will be the same as for the HG diet.

Study Type

Interventional

Enrollment

44

Phase

  • Not Applicable

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
    • Massachusetts
      • Boston, Massachusetts, United States, 02111
        • Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University

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

20 years to 42 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy men and women (based on standard laboratory tests and a screening examination)
  • 20-42 years of age
  • BMI in the range 25-29.9 kg/m2
  • Proportional representation of minorities in the Greater Boston Area (7 percent Black, 11 percent Hispanic, 82 percent non-Hispanic white)
  • Able to accurately complete a food record
  • Stage of change >1 for weight loss and changing dietary intake
  • Must have an immediate adult family member who is supportive of weight loss

Exclusion Criteria:

  • Known serious disorders that affect longevity, energy metabolism, body composition and immune responsiveness, including diabetes, cancer, heart disease, cachexia, eating disorders (anorexia and bulimia and any vomiting for means of weight control), depression, alcoholism, inflammatory disorders and AIDS, and individuals taking medicine that is anticipated to influence lifespan or energy metabolism
  • Abnormal kidney function as assessed by serum creatinine, BUN and urinalysis, and abnormal liver function as assessed by SGPT, SGOT alkaline phosphatase, and bilirubin, abnormal normal thyroid function as assessed by serum T4 and TSH and fasting serum glucose levels <125 mg/dl
  • Smoking, highly restrained eating, reported endurance training (participation in sports or training >12 hours per week), alcohol intake of 14 oz. per week or more, major medical and/or psychiatric disorders, plans to have a child within 3 years (1 year for Pilot study), past childbearing (for women) within the last 2 years, or breastfeeding within the past year
  • Amputees
  • Have required treatment for any psychiatric disorder
  • Gained or lost >15 lb weight within the past year, or taking medications known or suspected to have an important influence on lifespan, energy metabolism, body composition or immune function
  • Early death from cardiovascular diseases, cancer, or a diabetes-related illness (before the age of 45 years) in one or both of the parents
  • Unable to remain in the program for at least 1 year, or unsuitable for home-based programs (including individuals reporting binge eating disorders or clinical depression, and women intending to become pregnant)

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: Double

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Changes in body weight, body fatness and total energy expenditure at baseline, 3, 6, and 12 months of caloric restriction (CR).

Secondary Outcome Measures

Outcome Measure
Changes in blood pressure, insulin sensitivity and secretion, resting metabolic rate, bone mineral density, disease incidence, cognitive function, immune function, oxidative stress parameters, fertility hormones at baseline, 6, and 12 months

Collaborators and Investigators

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

Sponsor

National Institute on Aging (NIA)

Investigators

  • Principal Investigator: Susan B. Roberts, PhD, Tufts 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

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

November 1, 2002

Study Completion

December 1, 2004

Study Registration Dates

First Submitted

September 13, 2005

First Submitted That Met QC Criteria

September 13, 2005

First Posted (Estimate)

September 16, 2005

Study Record Updates

Last Update Posted (Estimate)

November 9, 2006

Last Update Submitted That Met QC Criteria

November 8, 2006

Last Verified

November 1, 2006

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • AG0044
  • 3U01AG020480 (NIH)

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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