Pilot Study of Time Restricted Feeding as a Weight Loss Intervention
Condition: Obesity
MeSH terms: Weight Loss
Study type: Interventional

Summary: 
      The circadian timing of Energy Intake (EI) has emerged as a key factor in the regulation of
      body weight. Studies have suggested that eating later in the evening or at night when the
      circadian system is promoting sleep adversely influences weight loss. In contrast,
      restricting EI to a short window during waking hours and extending the length of the
      overnight fast (i.e., time restricted feeding, TRF) may be a practical and useful weight loss
      strategy. The overall objective of this proposal is to provide a foundation to inform the
      design of a future large-scale trial to evaluate the efficacy of TRF in generating weight
      loss. The investigators aims are to: 1) Assess processes critical for the success of a
      large-scale trial comparing the efficacy of a reduced calorie diet with time restricted
      feeding (RCD+TRF) versus standard RCD on weight loss; 2) Develop methodology to assess
      compliance to the RCD+TRF versus standard RCD program and collect preliminary data on whether
      the programs have differential effects on free-living behaviors (EI, appetite, physical
      activity, and sedentary behavior); and 3) Measure metabolic responses to RCD+TRF versus
      standard RCD to determine candidate mechanisms related to weight loss at 12wks and weight
      maintenance at 6mo post-intervention. The investigators primary hypothesis is that weight
      loss will be greater in the TRF group compared to the RCD group.
    

Detailed description: 
      The circadian timing of energy intake (EI) has emerged as a key factor in the regulation of
      body weight. Studies have suggested that eating meals later in the evening or during the
      biological night when the circadian system is promoting sleep adversely influences the
      success of weight loss therapy. In contrast, restricting EI to a short window during waking
      hours and extending the length of the overnight fast (i.e., time restricted feeding, TRF) may
      be a practical and useful strategy for promoting weight loss and weight maintenance. However,
      potential benefits of adding TRF to a weight loss program have yet to be evaluated in a
      well-controlled clinical study. The overall objective of this proposal is to provide a
      foundation to inform the design of a future large-scale trial to evaluate the efficacy of TRF
      in generating weight loss. The investigators overall hypothesis is that feasibility,
      adherence, and acceptability of a weight loss intervention using TRF in the setting of a
      reduced calorie diet (RCD) - RCD+TRF - will be similar to compliance with an intervention
      using a reduced calorie diet alone (RCD), suggesting acceptability for a future large-scale
      trial. In this 12-week pilot and feasibility study, 30 overweight and obese individuals will
      be randomized 1:1 to RCD+TRF (EI restricted to a 10-hour window starting 1 hour from habitual
      waking time) or standard RCD (no restriction on feeding duration). Additional follow-up will
      occur at 6 months to collect pilot data on weight maintenance. Measures include feasibility,
      acceptability and adherence to the interventions, body weight, body composition (Dual-energy
      X-ray absorptiometry (DXA)), EI (smart phone application), physical activity (PA,
      accelerometery), glucose variability (continuous glucose monitoring, CGM), sleep
      (questionnaires and polysomnography), and nocturnal substrate metabolism (room calorimetry).
      The specific aims (SA) are as follows:

      Specific Aim 1a. To evaluate the feasibility and acceptability of a 12-week TRF intervention
      compared to a standard dietary weight loss intervention (i.e. RCD). Feasibility of enrollment
      and retention, and acceptability of the intervention will be assessed in adults with obesity
      meeting inclusion/exclusion criteria proposed for the future large-scale trial. The
      investigators will assess adherence to the weight loss programs, as measured objectively with
      a novel smartphone application and verified with CGM data, and subjectively with the use of
      questionnaires.

      Specific Aim 1b. To assess the efficacy of RCD+TRF compared to RCD alone in producing weight
      loss at 12 weeks and reducing the risk of weight regain after 6 months of follow-up.
    

Intervention name(s): Reduced Calorie Diet (RCD); Time Restricted Feeding (TRF)
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Participants will be given an individualized calorie goal. Participants in this group will also receive a 12 week comprehensive group-based behavioral weight loss program and will be instructed in specific strategies to support RCD.; Participants will be given an individualized calorie goal. Participants in this group will also receive a 12 week comprehensive group-based behavioral weight loss program and will be instructed in specific strategies to support RCD. Participants in this group will also instructed to eat only during a window of 10 hours, starting within 3 hours of waking. They will also be instructed in specific strategies to support TRF including: strategies to deal with hunger outside eating windows, distraction techniques, and choosing a balanced diet/appropriate portions during feeding windows.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment