Effects of a Daily Time-Restricted Feeding Protocol on Diet Quality

This 8-wk randomized-controlled, parallel arm trial will examine the effects of a daily 18 h fast (TRF protocol) compared to a daily 8-h (CON protocol) on (1) diet quality, (2) cardiometabolic health, and (3) anthropometry in college students enrolled at ASU. Institutional Review Board (IRB) approval will be granted prior to recruitment and commencement of trial activities. Participants will be stratified by age, waist circumference, gender, and METS (activity score) and randomly assigned to one of two study arms: intervention and control. \[Women will begin the trial within 5 days of menses.\] Participants in the intervention arm of the study will consume food and beverages of their choice within one hour of waking and the feeding window will extend 6 hours. Beyond these hours, participants will observe a prolonged fast (i.e., an 18-h overnight fast). Participants in the control arm of the study will fast each night for 8 hours. During fasting hours, participants will only be permitted to consume non-caloric beverages (preferably water only but unsweetened and non-caloric coffee, tea, etc. will be permitted). Participants will adhere to their daily protocol for 8 weeks. Participants will not receive diet instruction other than 'to fast' and are told to maintain their typical physical activity patterns for the duration of the trial. Participants will choose one 'cheat-day' per week where they are excused from the fasting protocols; this day of the week will be consistent throughout the 8-week trial. Diet quality will be measured by the REAP-S questionnaire, 24-h recalls will be obtained by a registered dietitian via a three-step multiple-pass interview method, a registered nurse or radiology technician will obtain fasting blood draws for biomarkers, and trained research personnel will obtain measures of anthropometry.