The aim of this pilot feasibility and acceptability, randomized clinical trial will be to examine the effects of two-time restricted eating (TRE) interventions on weight loss maintenance (WLM). This study will be conducted in 40 individuals with non-surgical weight loss of ≥5% initial body weight recruited from the NYU Langone Health Weight Management Program and NY-MOVE! Weight Management Clinic at the Manhattan VA. Measurements will occur at baseline, 4 and 12 weeks. Participants will be randomized with equal allocation to 2 groups: (1) TRE6 or (2) TRE10. The TRE6 will restrict their eating window to 6 hours per day and the TRE10 to 10 hours per day.

Inclusion Criteria:

• ≥5% non-surgical weight loss from NYULH-WMP and NY-MOVE! Endocrinology Weight Management Clinic in the last 3 months
• BMI between 20.5 - 45 m/kg2
• between the ages 25 to 65 years old
• own a smartphone or willing to use a smartphone if provided for self-monitoring
• Eating window >12 h per day
• <150 mins/wk of physical activity
• log at least 2 meals into the smartphone app on ≥5 days

Exclusion Criteria:

• <25 years or >65 years of age
• Body weight in excess of 400lbs (181.4kg)
• pregnant, trying to get pregnant or breastfeeding
• previous or planned bariatric surgery
• previous or current history of eating disorder
• ongoing participation in another weight-management research study
• continued participation in a weight loss program other than the proposed study
• currently on appetite suppressants
• currently following intermittent fasting or skipping meals
• eating window <11h 59min/day
• perform overnight shift work more than once a week
• work that includes travel across one or more time zones
• currently on anti-obesity medications (AOMs) such as, GLP-1 analogues (exenatide, tirzepatide, semaglutide, liraglutide) and pancreatic lipase inhibitors (Orlistat/Xenical and Alli)
• prescribed medications expected to result in weight loss such as Orlistat, Naltrexone, Bupropion, Lorcaserin, Phentermine, Topiramate, or Liraglutide, and who are unwilling to delay treatment with these medications for the next 3 months
• unable or unwilling to provide informed consent
• unable to participate meaningfully in the intervention (e.g., uncorrected sight and hearing impairment)
• unwilling to accept randomization assignment
• unable to log at least 2 meals into the smartphone app on ≥5 d during the screening period
• have type 1 or other conditions that would preclude restricted eating windows
• have type 2 diabetes with a HbA1c >7.0% on medications except for metformin alone
• narcolepsy
• active cancer
• organ dysfunction
• current steroid use
• daytime sleepiness with the Epworth Sleepiness Scale >10
• severe insomnia with a score ≥15 on the Insomnia Severity Index
• >2.5 kg additional weight loss during run-in phase (weight regain is not an exclusion criteria)

The de-identified participant data from the final research dataset used in the published manuscript will be shared upon reasonable request beginning 9 months and ending 36 months following article publication or as required by a condition of awards and agreements supporting the research provided the investigator who proposes to use the data executes a data use agreement with NYU Langone Health. Requests may be directed to: [collin.popp@nyulangone.org]. The protocol and statistical analysis plan will be made available on Clinicaltrials.gov only as required by federal regulation or as a condition of awards and agreements supporting the research.

Beginning 9 months and ending 36 months following article publication or as required by a condition of awards and agreements supporting the research.

The investigator who proposed to use the data will be granted access upon reasonable request. Requests should be directed to collin.popp@nyulangone.org. To gain access, data requestors will need to sign a data access agreement.