Preventing Obesity Using Novel Dietary Strategies
Condition: Cardiovascular Diseases; Heart Diseases; Obesity
MeSH terms: Cardiovascular Diseases; Heart Diseases; Obesity
Study type: Interventional

Summary: 
      The purpose of this study is to test the effectiveness for weight loss and weight maintenance
      of four diets differing in macronutrient composition: moderate in fat (40 percent energy)
      with two different protein levels (15 percent and 25 percent), and low in fat (20 percent
      energy), also with 15 percent and 25 percent protein levels. The study is only accepting
      participants in the Boston, Massachusetts or Baton Rouge, Louisiana area. For further
      enrollment information in Boston or Baton Rouge, see Eligibility Criteria or Design
      Narrative.
    

Detailed description: 
      BACKGROUND:

      Obesity is a growing problem whose importance is reflected in the resources that are expended
      each year by a large section of the population on weight reduction drugs and therapies.
      Although numerous weight loss diets are available, there is little agreement in the
      scientific literature or the lay press as to the amount of fat, protein, and carbohydrates
      that would comprise the most efficacious diet for weight loss and long term weight loss
      retention. Reliable information about the effectiveness of low calorie diets with differing
      macronutrient composition is clearly needed and of paramount importance to inform the choice
      of a weight reduction diet.

      DESIGN NARRATIVE:

      The study tests the effectiveness for weight loss and weight maintenance of four diets
      differing in macronutrient composition: moderate in fat (40% energy) with two different
      protein levels (15% and 25%), and low in fat (20% energy), also with 15% and 25% protein
      levels. The moderate-fat diet will be patterned after a Mediterranean diet. All four dietary
      approaches will be low in saturated fat, and will involve reduction in total energy intake.
      Each diet is deemed practical and suitable for public health recommendations, and each would
      be expected to have a favorable effect on cardiovascular disease risk factors. All
      participants will receive a state-of-the-art behavioral therapy program standardized across
      the two centers in Boston and Baton Rouge. An estimated 800 men and women, age 30-70 years,
      body mass index (BMI) 25-40 kg/m2, will be randomized among the 4 dietary treatments. The
      primary outcome variable will be change in total body weight from baseline to 2 years.
      Secondary outcomes related to obesity are body fat, BMI, waist circumference, visceral fat,
      and hepatic and skeletal muscle fat. Other outcomes are psychological factors (diet
      satisfaction, satiety, food craving, dietary restraint, disinhibition and hunger, and quality
      of life); major cardiovascular risk factors (blood pressure, low density lipoprotein [LDL]
      cholesterol, high density lipoprotein [HDL] cholesterol, and triglycerides); prevalence of
      the metabolic syndrome; blood glucose, insulin, and hemoglobin A1C; emerging cardiovascular
      risk factors (apolipoprotein B, VLDL and LDL particles with apolipoprotein C-III,
      lipoprotein[a]); microalbuminuria; and bone mineral content. The primary results will be
      straightforwardly applicable to public health and clinical guidelines for obesity and will
      increase our understanding of the biology of obesity and weight loss.

      The study is only accepting participants in the Boston, Massachusetts or Baton Rouge,
      Louisiana area. For Boston participants, contact: 617-998-1047 or www.poundslost.org. For
      Baton Rouge participants, contact: schoensj@pbrc.edu or 225-763-2623.
    

Intervention name(s): Four Diets Differing in Macronutrient Composition; Diets Low in Saturated Fat
Intervention type(s): Behavioral; Behavioral
Primary purpose: Prevention