Time Restricted Eating for WeIght LoSs MainTenance-2

The TWIST 2.0 Study is a 12-month, 2-arm RCT in adults with recent weight loss. We will examine the efficacy of TRE on weight (Aim 1a) and fat mass (Aim 1b) regain, and describe changes in subjective appetite following a mixed-meal tolerance test (Exploratory). Potential participants will be screened via telephone and eligible participants will attend an in-person screening visit where they will complete questionnaires and have their height and weight measured. We will perform a 4-week run-in period to establish weight stabilization and measure eating patterns before randomization. Eligible participants following the run-in period will be randomized with equal allocation to one of the 2 arms: 1) TRE intervention ≤10-hr/day TRE intervention); or 2) CON. At baseline, 6 and 12 month measurements, participants will complete a bioelectrical impedance analysis (BIA) and dual energy x-ray absorptiometry (DEXA) scan by a certified radiology technician. Within each arm, participants will be randomized to either complete or not complete a mixed meal tolerance test in which they will consume a small portion of a protein shake and complete a visual analog scale (VAS) on their subjective hunger/fullness. Participants in both arms will receive one-page handouts (i.e., "advice") on topics to assist with weight maintenance. The only between-group differences are the TRE arm will be instructed to follow a restricted eating window of ≤10 hr/day, self-monitor foods and beverages into a smartphone app, measure body weight using a Bluetooth-enabled scale, and receive behavioral counseling directed at sustaining adherence to the TRE intervention. The CON arm will be unrestricted in their eating window and encouraged to eat a habitual breakfast, lunch, and dinner. No additional contact will be made between the CON arm and interventionist during the 12 months unless we schedule a measurement visit. Digital newsletters will be provided every month for the first 6 mos, and then every other month containing complementary information on WLM to engage participants in the CON arm. The same newsletters will be going to the TRE.

Inclusion criteria

• ≥5% non-surgical weight loss in the last 3 mos;
• current BMI 20.5-45 mg/kg2;
• between the ages 25 to 65 years old;
• own a smartphone or willing to use a smartphone if provided for self-monitoring. For in-person screening, eligible participants will provide signed informed consent and have their temporal eating patterns measured.

Exclusion criteria

• 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;
• taking medications that affect body weight or would preclude TRE;
• 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 for 70% (~20 days) during of the run-in period;
• have type 1 or type 2 diabetes, or other conditions that would preclude restricted eating windows;
• narcolepsy,
• >2.5 kg additional weight loss during run-in phase (weight regain is not an exclusion criteria);
• is non-English speaking (the mCC app is currently only available in English).