Randomized Study of Daytime vs. Delayed Eating: Effect on Weight and Metabolism
Condition: Obesity
Study type: Interventional

Summary: 
      The purpose of this study is to determine if, controlling for eating and sleep timing,
      caloric intake, and exercise, daytime vs. delayed eating affects body mass, adiposity, and
      energy metabolism in healthy adults.
    

Detailed description: 
      The study consists of 4 phases - screening & baseline assessment, eating condition 1,
      wash-out period, and eating condition 2. Before and after each phase participants will
      complete a 28-hour inpatient assessment at the Clinical and Translational Research Center
      (CTRC) of the Hospital of the University of Pennsylvania to study the impact of one's eating
      on body weight and fat content, metabolism, and certain markers of metabolism in the blood.

      Screening In order to participate in this study the participants must undergo a complete
      physical examination and tests of blood and urine. These tests will determine if participants
      have any conditions that would prevent them from participating in the study, including
      diabetes or any serious uncontrolled medical condition that may interfere with their
      participation in the study. Other conditions that would prevent them from taking part are
      pregnancy or nursing, a sleep disorder, the use of certain medications, or night-shift work.
      A urine pregnancy test will be given to women at this screening visit.

      Participants will also complete several surveys of a psychological nature and participate in
      a clinical interview. Sleep and exercise schedules are important and will be reviewed during
      their visits to see if they match with the study requirements. During the 10 days of the
      screening assessment, participants will keep a log in which they will record all food and
      beverages that they consume. They will also use these logs to record when they sleep and
      exercise. Their activity will be measured by a small electronic wrist activity recorder,
      called an Actigraph (about the size of a wrist watch), during this time. This recorder,
      similar to a pedometer, records all activity from the arm, and is very useful in determining
      if and when they get up at night. Study staff will explain how to keep this information
      during the baseline visit. They will return the activity recorder and log to Dr. Allison for
      analysis at the end of the 10-days. They are expected to return all study materials,
      including the Actigraph, log, and questionnaires.

      Assessments Following successful completion of the screening period, they will complete the
      first of four assessment visits. This visit will include 28 hours (overnight) spent at the
      CTRC, where their meals and snacks will be provided.

      They will arrive at the CTRC at the Hospital of the University of Pennsylvania at 7 AM.
      Starting at 8 AM, their blood will be drawn every four hours. A thin needle (an introducer)
      will be inserted into a vein in their forearm, much like an IV line. Very small blood
      samples, 10mL (2 teaspoonfuls), will be collected every four hours from 8:00 AM on Day 1
      through 8:00 AM on Day 2. From this blood study staff will measure hormones related to
      metabolism, sleep, and stress. They will be provided meals and snacks during this time, and
      they are free to watch television or use their computer or participate in other sedentary
      pastimes while they are there.

      After the blood draws end at 8 AM on the second morning, their metabolic rate will be
      measured. Participants will be asked to fast for 10 hours overnight (they will not be able to
      eat or drink anything except water for 10 hours starting at 10 PM the night before). Then
      study staff will measure their resting metabolic rate for 20 minutes. During the
      measurements, they will lay on their back in bed with a plastic hood/canopy over their head
      and neck. They will lay still and breathe normally while the air they inhale and exhale is
      collected in the canopy/hood and analyzed using a machine that is connected to the
      canopy/hood.

      Participants will be discharged from the hospital, and research staff will escort them to the
      Center for Weight and Eating Disorders where their body composition will be measured using
      dual energy X-ray absorptiometry (DEXA). During this test, X-ray pictures of their body will
      measure how much fat and muscle are present. They will lie flat on a table and a machine will
      take pictures of different areas of the body. This test will last about 30 minutes. This will
      conclude the assessment visit.

      Eating Conditions & Assessments Upon completion of the baseline assessment, participants will
      be randomly assigned to start with one of two eating conditions: 1) Daytime or 2) Delayed,
      and then they will switch and eat on the other schedule for the final part of the study. If
      they are assigned to the Daytime eating condition first, they will be asked to consume all of
      their meals and snacks each day between 8 AM and 7 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 PM and 11 PM each day. They will eat on these schedules for 8 weeks each.

      During the two 8-week eating condition periods, all of their meals and snacks will be
      provided by the research kitchen and will be delivered to themby a member of the research
      staff twice per week. They will be provided a personalized menu and asked to track each food
      item they consume. They will also be asked to record any beverages they consume on this menu
      (beverages will not be provided). If occasionally they do not eat the meals provided, they
      will be asked to use their smart phone or electronic device to send a picture of their food
      to the study team before they eat it, and again if any food is not eaten when they have
      finished their meal. They will be asked to wear an Actigraph for the duration of the study,
      and study staff will deliver new devices and collect used devices one time per week. They
      will be sent and asked to respond to daily queries by text message or email regarding their
      eating, sleeping, and exercise. At the end of the 8 weeks, they will complete the second
      overnight assessment visit (as described above).

      For two weeks following this second assessment, they will be asked to eat as they normally
      would. During this "wash-out" period they will eat what and when then would like. They will
      then complete the third overnight assessment visit before starting the second eating
      condition (Delayed for those initially assigned to the Daytime schedule; Daytime for those
      initially assigned to the Delayed schedule). They will be asked to eat on this new schedule
      for 8 weeks. They will then complete the fourth and final overnight assessment. After this
      final assessment visit, their 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