Predicting Adherence to a Heart-Healthy Diet in Lean and Obese Individuals
Condition: Obesity; Overweight
MeSH terms: Overweight
Study type: Interventional

Summary: 
      Background:

      - Sticking to a diet plan can be difficult, but is important for many different health
      reasons. Some people seem to have a harder time following and sticking to a diet plan than
      others. It is not clear whether people of different weights (lean or obese) might have
      differences in the way they adhere to diet plans. Researchers want to study three different
      groups of people based on their body mass index (BMI), which measures people based on their
      weight and height. The study will place the participants on a 6-week diet and see how well
      they follow the diet. The information from this study may help develop better weight-loss
      plans and healthy diet ideas.

      Objectives:

        -  To understand what factors affect adherence to a diet plan.

        -  To collect information for future studies that may improve people's ability to stick to
           diets.

      Eligibility:

      - Individuals at least 18 years of age who are lean (BMI between 18.5 and 25) or obese (BMI
      greater than 30).

      Design:

        -  Participants will be screened with a physical exam and medical history. Blood and urine
           samples will be collected. They will have a full-body scan to measure fat and muscle.
           They will also answer questions on eating behaviors, mood, and desire to change eating
           patterns.

        -  Participants will be separated into three groups. Each group will have a different diet.
           The lean group will have a heart-healthy diet designed to maintain the same weight. One
           of the obese groups will also have a heart-healthy diet designed to maintain the same
           weight. The other obese group will have a heart-healthy weight loss diet. In all groups,
           all food will be provided by the study doctors. Participants should not eat any food
           other than that provided for the study.

        -  Everyone will start with a 1-week food testing period to find the right number of
           calories for each group. After this first week, participants will attend one diet
           counseling session per week and will be contacted randomly once a week to check on the
           foods they have had in the past 24 hours. Participants will complete daily food diaries
           on paper as well as daily food records using a smart phone.

        -  Participants will come to the clinic twice a week to pick up the diet food. On one of
           those days, they will also have their counseling session.

        -  The study will last for 6 weeks. At the final study visit, participants will repeat the
           tests from the screening study.
    

Detailed description: 
      Adherence, or "sticking to your diet" is important for successful initial weight loss and
      keeping off the weight over the long term (1). While early behavioral and dietary adherence
      have been associated with greater weight loss, sticking to a diet plan is difficult. It is
      not clear if adherence to any diet plan (even one which does not produce weight loss) is hard
      or whether people who are overweight have more difficulty with adhering to diet plans
      compared to people who are relatively lean.

      The main aim of this study is to evaluate dietary adherence in 3 groups of individuals
      participating in a 6-week heart-healthy dietary intervention program. Two groups [1 (BMI < 25
      kg/m(2)) and 2. Obese (BMI greater than or equal to 30 kg/m(2))] will receive a heart-healthy
      diet designed to maintain their weight, and the third group [3. Obese] will be given a
      heart-healthy diet that is 35% less than their daily calorie needs to lose weight.
      Participants will attend one counseling session per week and will be contacted randomly
      1x/week by study staff for completion of a 24-hour dietary recall. They will complete daily
      food diaries and daily records using smart-phones. Prior to starting the assigned
      heart-healthy dietary intervention, participants will complete questionnaires that include
      questions about how motivated they are to follow a diet, lose weight, and change eating
      patterns. These findings may help us understand what factors affect adherence, and help us
      design weight loss studies that improve people's ability to stick to diet interventions.
    

Intervention name(s): Underfeeding diet; Weight maintaining diet
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Heart healthy diet with 35% reduced calories; Heart healthy weight-maintaining diet
Other intervention name(s): UF; WMEN
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Food Intake; Weight Loss; Compliance