Time Restricted Feeding and Metabolic Rhythms
Condition: Obesity; Diabetes
Study type: Interventional

Summary: 
      Current guidelines for the prevention and treatment of obesity focus on caloric restriction
      diets and increasing physical activity, but long-term compliance to these strategies is poor.
      The timing of meal intake relative to the light-dark and sleep-wake cycle is rarely
      considered in metabolic health; and modifying meal timing is likely easier to implement in
      daily life than reducing caloric intake and/or increasing physical activity. This project
      will test whether restricting the timing of energy intake to a short-defined period during
      wakefulness can be used to improve fuel utilization patterns and enhance circadian rhythms in
      metabolic tissues to optimize health.
    

Detailed description: 
      Time restricted feeding (TRF; eating within <10-h period followed by >14-h fast) is a
      promising meal timing paradigm that in rodent studies improves multiple health indicators.
      When provided access to a high-fat diet ad libitum, mice rapidly gain weight. However, when
      fed the same diet under TRF conditions (food access restricted to an 8-h window during the
      active phase) mice appear to be protected from excessive weight gain and metabolic diseases.
      Preliminary studies in humans are showing improvements in 24-h glucose variability, fat
      oxidation, and blood pressure with TRF aligned to the early portion of the day compared to
      the ad libitum feeding schedule. A major research gap is whether the timing of the feeding
      window relative to sleep modifies metabolic responses. In a recent pilot and feasibility
      study incorporating TRF into a weight loss intervention the researchers asked participants to
      consume all food within a 10-h window to starting 1-h after waking for 12-weeks. The
      researchers' design choice was based on data showing that consuming energy in the evening is
      related to a two-fold increase in obesity risk. There also appears to be reduced weight loss
      effectiveness in dieters who consume the main meal later in the day. Some of the participants
      in the weight loss trial reported difficulty adhering to the early feeding schedule because
      it does not align well with social schedule (e.g., eating dinner with the family in the
      evening). Therefore, an important clinical question is whether late or mid-day TRF will
      result in similar metabolic benefits compared to the early TRF paradigm that has been tested
      in other studies.

      Additional rationale for studying early vs. late timed feeding is to address a fundamental
      question, "can timed meals shift the timing of metabolic rhythms?". Peripheral circadian
      clocks located in liver, adipose, and muscle tissue are sensitive to meal timing and control
      daily oscillations in fuel utilization and storage. A small study of 8 men demonstrated that
      a 5-h delay and meal timing was sufficient to delay the rhythmic expression of clock genes in
      white adipose tissue. Therefore, the investigators will leverage the design of the present
      study to examine the impact of meal timing on peripheral circadian rhythms in metabolism and
      their alignment to the sleep cycle.
    

Intervention name(s): Time Restricted Feeding
Intervention type(s): Behavioral
Intervention description(s): Consuming energy during a short interval during the day
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Weight loss; Diet