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Dietary Energy Restriction and Metabolic Aging in Humans

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00183027
Recruitment Status : Completed
First Posted : September 16, 2005
Last Update Posted : November 9, 2006
Information provided by:
National Institute on Aging (NIA)

Brief Summary:
The purpose of this study is to develop an effective calorie restricted diet.

Condition or disease Intervention/treatment Phase
Obesity Behavioral: Dietary composition and energy intake Not Applicable

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.

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Study Type : Interventional  (Clinical Trial)
Enrollment : 44 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double
Primary Purpose: Treatment
Official Title: Dietary Energy Restriction and Metabolic Aging in Humans
Study Start Date : November 2002
Study Completion Date : December 2004

Resource links provided by the National Library of Medicine

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

Secondary Outcome Measures :
  1. 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

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   20 Years to 42 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

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)

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00183027

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United States, Massachusetts
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University
Boston, Massachusetts, United States, 02111
Sponsors and Collaborators
National Institute on Aging (NIA)
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Principal Investigator: Susan B. Roberts, PhD Tufts University
Publications of Results:
Other Publications:

Publications automatically indexed to this study by Identifier (NCT Number):
Layout table for additonal information Identifier: NCT00183027    
Other Study ID Numbers: AG0044
3U01AG020480 ( U.S. NIH Grant/Contract )
First Posted: September 16, 2005    Key Record Dates
Last Update Posted: November 9, 2006
Last Verified: November 2006
Keywords provided by National Institute on Aging (NIA):
Dietary restriction
Caloric restriction