Abstract
<b>Background:</b> Humans exhibit eating windows ranging between 12-15 hours daily. Extensive eating windows may promote excess energy consumption leading to weight gain and poor cardiometabolic health. Time restricted eating is a behavioural intervention positioning all eating occasions within a shorter timeframe < 12 hours to aid weight loss and metabolism.
<b>Methods:</b> A proof-of-concept questionnaire [Study 1] explored public opinion on implementing a 3h restriction to habitual eating windows. [Trial 2.1] investigated the physiological effects of time-restricted eating consisting of a symmetrical 1.5 h delay and advance to first and last eating occasions. The impact after 5-weeks of time-restricted eating on appetite hormones, subjective appetite and preoccupation with food was measured in [Trial 2.2]. [Study 2.3] involved qualitative interviews to assess participant experiences following time-restricted eating, along with identifying some of the social and behavioural factors affecting adherence.
<b>Results:</b> Most respondents had an eating window between 10-14 h on workdays and free days [Study 1]. For workdays (n=132/221) and free days (n=125/223), participants with an eating window > 12 h indicated favourability towards reducing their eating window by 3 h [Chapter 2]. Trial 2.1 did not reveal any significant changes to body anthropometrics, blood pressure or fasted blood glucose, cholesterol, or insulin after 5-weeks [Chapter 4]. In Trial 2.2, there were no significant differences to fasted ghrelin, leptin, subjective appetite, and preoccupation with food [Chapter 5]. Adherence to the protocol was ~63% in [Study 2.3]. Barriers to adopting TRE included work schedules, social events, and family life [Chapter 6].
<b>Conclusion:</b> Time-restricted eating is a well-received alternative to calorie restricted diets targeting weight loss. Social and behavioural factors may restrict the efficacy of time-restricted eating in the free-living environment, however. The development of personalised and flexible time-restricted eating protocols may help to navigate the barriers to adherence leading to improved health related outcomes.