Daytime vs. Delayed Eating Among Obese Individuals
Condition: Obesity
Study type: Interventional

Summary: 
      The randomized, cross-over design study is designed to determine how timing of eating affects
      weight, adiposity, energy metabolism, and gene expression. Obese participants will be
      provided isocaloric meals and snacks to be consumed in one of two prescribed eating
      conditions -- daytime eating and delayed eating.
    

Detailed description: 
      The study consists of the following phases - screening, assessment visit 1, eating condition
      1, assessment visit 2, a wash-out period, assessment visit 3, eating condition 2 and
      assessment visit 4, as discussed in detail below. The assessment visits will all consist of
      the same procedures and will take place at the Center for Human Phenomic Science (CHPS) of
      the Hospital of the University of Pennsylvania before and after each of the eating conditions
      (four times total). The four 28-hour inpatient assessments will consist of blood draws,
      adipose (fat) tissue sampling, a dual energy X-ray absorptiometry (DEXA) scan, and a resting
      metabolic rate test.

      During the screening period in order to determine eligibility, participants must complete a
      2-part screening visit; This includes:

        1. A complete physical examination

        2. Tests of blood to screen for any conditions such as diabetes or any serious,
           uncontrolled medical condition that may interfere with participation in the study.

        3. An Electrocardiogram (EKG) test

        4. Urine Pregnancy Test

        5. Urine Drug Screening

        6. the completion of several self-report questionnaires and structured interviews

      During the screening period, participants will also be asked to keep a 10-day food log where
      they will record all food and beverages consumed and their sleep and exercise schedule.
      Participants will be asked to wear an Actigraph wrist watch at this time.

      Following successful completion of the screening period, participants will complete the first
      of 4 assessment visits. All assessment visits will follow the same protocol.

      Assessment Visit Day 1 Procedures:

      The visit will include 28 hours (overnight) spent at the CHPS, where meals and snacks will be
      provided. At each of the assessment visits participants will be given a urine drug screening
      and, if appropriate, a pregnancy test. The lights will be dim in the hospital room to control
      for light.

      Participants will arrive at 7:00 am. Starting at 8:00 am, blood will be drawn every four
      hours. From this blood gene expression and hormones related to metabolism, eating, and sleep
      will be measured.

      Following the first blood draw, resting metabolic rate is measured for 45 minutes. Lunch is
      then provided, followed by a measurement of body composition using a DEXA scan. Next, the
      adipose tissue sampling procedure will begin. Lastly, the participants will complete a series
      of cognitive tests administered on a laptop.

      Participants will be provided meals and snacks during their visit and are free to watch
      television or participate in other sedentary pastimes while they are there.

      Assessment Visit Day 2 Procedures:

      After an overnight fast, participants will undergo the Frequently Sampled Intravenous Glucose
      Tolerance Test (FSIGT) on the morning of day 2.

      Following the FSIGT test, participants will be served a meal and during the first assessment
      visit, participants will be randomly assigned to start with one of two eating conditions for
      the next 8 weeks: 1) Daytime or 2) Delayed. Following randomization, participants will be
      discharged from CHPS and begin eating condition 1.

      If participants are assigned to the daytime eating condition first, they will be asked to
      consume all of their meals and snacks each day between 8:00 am and 7:00 pm. If they are
      assigned to the delayed eating condition first, they will be asked to consume all of their
      meals and snacks between 12 noon and 11:00 pm each day. Participants will eat on this
      schedule for 8 weeks. During the two, 8-week eating periods, all of the meals and snacks will
      be provided by the research kitchen. During the eating conditions, participants will be asked
      to complete daily self-report queries concerning their adherence to the food, sleep, and
      physical activity requirements of the study.

      Following eating condition 1, participants will return for assessment visit 2. This
      assessment visit follows the same procedures as all other assessment visits. Following
      assessment visit 2, participants will begin their 2 week washout period where they are
      instructed to eat as they normally would whenever they like. Following the two-week washout
      period, participants will return for assessment visit 3, after which they will begin eating
      condition 2. Following 8 weeks of eating condition 2 participants will return for their final
      visit, assessment visit 4. After this final assessment, participation in the study will be
      complete.
    

Intervention name(s): Eating Condition
Intervention type(s): Behavioral
Intervention description(s): Participants will be randomly assigned to eat per the prescribed eating condition for 8 weeks during eating condition 1. They will complete the alternate eating condition for 8 weeks during eating condition 2.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Randomized within subjects, cross-over design
Masking: None (Open Label)
Primary purpose: Other
Keywords: Metabolism; Eating; Circadian Rhythms