theFRESHstudy: FRequency of Eating and Its Influence on Satiety and Health
Condition: Healthy
Study type: Interventional

Summary: 
      Eating frequency may play an independent role in appetite regulation, overall caloric
      consumption and measures of long-term health or disease risk. Some literature recommends
      frequent eating, but pilot data suggest that this type of eating pattern may be harmful to
      health since it leaves the body in a perpetual fed state and increases systemic inflammation.
      Therefore, the investigators will conduct a clinical trial in 50 healthy adults to compare a
      low frequency eating pattern to a high frequency eating pattern in relation to blood-based
      markers of inflammation, metabolic health and appetite. Study results will be applied to
      recommendations for eating frequency in the context of an overall healthy diet.
    

Detailed description: 
      This proposal will investigate whether eating frequency influences health. Evidence-based
      recommendations are lacking for the optimal number of daily eating occasions. This is an
      important area of research because over the past 40 years Americans' eating habits have
      changed from three meals a day to a pattern whereby most people now have 6-8 daily eating
      occasions. Apart from potential increases in total energy intake, frequent eating leaves
      people in a constant postprandial state. This constant, modestly elevated glycemia disturbs
      the normal glucose-insulin and counter-regulatory hormone network balance and also disturbs
      downstream cell signaling pathways. A constant postprandial state may increase systemic
      inflammation and cause numerous other metabolic disturbances. As a result, eating frequency
      (EF) may be associated with risk of diet-related chronic diseases such as cardiovascular
      disease, cancer and diabetes, which are the major causes of morbidity, mortality and health
      care costs in the U.S. To better understand this phenomena the investigators propose a
      randomized, cross-over clinical trial to test a low-EF eating pattern (three eating
      occasions/day) vs. a high-EF eating pattern (six eating occasions/day) in relation to
      inflammation, an adipokine and appetite. The investigators hypothesize that compared to
      eating three times/day, eating six times/day will increase biomarkers of systemic
      inflammation, will decrease a beneficial adipokine and will increase both biomarkers and
      self-reported measures of appetite. The investigators will test their hypothesis with these
      specific aims: 1) To test the effects of low vs. high eating frequency on inflammatory
      biomarkers (fasting high-sensitivity C-reactive protein, Interleukin-6 and tumor necrosis
      factor-α,) and a beneficial adipokine (adiponectin); 2) To test the effects of low vs. high
      eating frequency on appetite [daily ratings of perceived appetite and serial ratings during a
      six-hour appetite testing session] and biomarkers involved in appetite regulation and food
      intake (leptin, ghrelin, peptide YY, and cholecystokinin). The investigators will enroll n=50
      males and females who are normal weight, overweight or obese. Participants will complete two
      3-week long isocaloric intervention periods in random order [low EF (three eating
      occasions/day) and high EF (six eating occasions/day)]. Participants will be free-living and
      eating their own food using study-provided structured meals plans. Study staff will provide
      on-going support and instruction to maximize adherence to the protocol. Fasting blood samples
      will be collected at the beginning and end of each study phase. The investigators will test
      for the intervention effect by using the GEE modification of linear regression to compare
      mean biomarker response (intervention effect) for each study phase. On the last day of each
      intervention period, participants will complete 6-hour appetite testing sessions where two
      test meals will be provided in the low-EF phase and four test meals will be provided in the
      high-EF phase. Serial appetite ratings and bloods will be collected to assess perceived
      appetite and hormones of appetite and satiety. Results from this investigation will be used
      to form guidelines for eating frequency in the context of an overall healthy diet.
    

Intervention name(s): High Eating Frequency; Low Eating Frequency
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Free-living participants will complete a 21-day high eating frequency (high EF) Phase in which consume all daily energy at 6 eating occasions.; Free-living participants will complete a 21-day low eating frequency (low EF) Phase
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: meal frequency; eating frequency; ingestive frequency; Positive energy balance; Satiation