Understanding how weight loss interventions impact appetite in real-life settings and over time is important. In clinical trials, appetite is often measured at a single time while participants are in hospital (Chapter 2). As appetite levels fluctuate naturally throughout the day, this could mean that subtle changes may go undetected. This thesis reports on the design and development of ‘momentary appetite capture’ (MAC), an ecological momentary assessment tool to track appetite. MAC combines automated text messaging with an online platform to regularly elicit ratings of appetite and virtual portion-size selection throughout the day. Chapter 3 reports on two feasibility studies that were conducted to develop and test the feasibility of MAC. Here, initial test-retest reliability and acceptability of MAC were established. In Chapter 4, whether MAC could be useful in capturing individual differences in appetite and how these differences relate to dietary restraint was explored. Results suggested that restrained eaters experience lower hunger and select smaller portions throughout the day. Following this, MAC was utilised to investigate whether the experience of intermittent fasting modifies perceptions about the need to eat regularly (Chapter 5). Next, MAC was applied in clinical trials to assess how a novel weight loss product (Sirona) impacts appetite over time. In a Phase 1 first-in-human trial, participants regularly completed MAC, and preliminary evidence indicated that Sirona may suppress appetite and modify food preference (Chapter 6). Then, in a Phase 2 randomised controlled trial, MAC was applied longitudinally to explore the effects of Sirona on hunger, fullness, desire to eat and prospective portion-size selection (Chapter 7). Together, findings from this PhD suggest that MAC is a useful tool to investigate daily appetite patterns. Future research could apply MAC to better understand mechanisms underpinning the effectiveness of weight-loss interventions, as well as to explore energy balance more broadly.
Optimising and utilising Momentary Appetite Capture: An Ecological Momentary Assessment tool developed to track changes in appetite and portion-size selection in real life settings and over time
Elsworth, R. (Author). 13 May 2025
Student thesis: Doctoral Thesis › Doctor of Philosophy (PhD)