Physiological and Neurocognitive Responses to Multisensory Food Cues in VR

This study aims to fill an important gap in the literature by examining the extent to which food craving responses can be enhanced by incorporating not only visual cues but also auditory, olfactory, and food-interaction-based experiences within a VR environment. Furthermore, by utilising objective biological indicators such as changes in saliva composition, blood glucose levels, and EEG recordings, the study aims to analyse VR-based food cue exposure not only through subjective assessments but also through objective data. In this respect, the study is expected to provide original contributions both conceptually and methodologically by enabling a deeper understanding of the mechanisms that increase food cravings and the modulation of these processes through VR technologies. The findings will provide a scientific basis for the development of therapeutic VR interventions to regulate food cravings in the future.

The original value of the study lies in the comprehensive monitoring of the effect of multi-sensory food cues presented in a VR environment on food cravings in individuals using physiological (saliva secretion and composition, blood glucose level) and neurocognitive (EEG recordings) measurements, and evaluating them comparatively with the responses to the same cues in a real environment. Although the effect of real-world food cues on food cravings has been studied in detail in the literature, the extent to which similar multi-sensory cues in VR environments trigger such responses has not yet been sufficiently clarified. Furthermore, studies investigating the effects of integrating additional sensory elements such as smell and food sounds to enhance presence in VR environments are quite limited.

This study will include a total of 34 healthy volunteers (both female and male) aged 18 and over, selected from among Marmara University students between November 2025 and March 2026, who meet the inclusion criteria for the study. Ethical approval for conducting the study was obtained from the Marmara University Faculty of Medicine Ethics Committee for Non-Drug and Non-Medical Device Research. The sample size was calculated using the G*Power 3.1 programme, based on the t-test for dependent samples. The calculations were based on a medium effect size (Cohen's d = 0.5), 80% statistical power, and a 5% significance level (α = 0.05). According to the power analysis performed based on these parameters, it was predicted that statistically significant results could be achieved with at least 34 participants in the study. Taking into account possible data losses, it was decided to invite 41 individuals, which is 20% more than the sample size. Considering the limited number of EEG devices and the time required for each experimental condition, the sample size was determined based on both scientific reasons and practical possibilities. The experimental procedure for each participant will be randomised using a Latin square design. If the targeted sample size cannot be achieved, the data collection process is planned to be extended until June 2026. Verbal and written informed consent will be obtained from all participants prior to the data collection process.

Whether participants meet the inclusion and exclusion criteria determined prior to the experimental procedure will be determined by the researcher using a pre-assessment form. Following the signing of the informed consent form, participants' anthropometric measurements will be taken; their body temperatures will be measured using a non-contact thermometer, and their blood glucose levels will be measured using an Accu-Chek glucometer. Subsequently, a demographic information form containing variables such as age and gender will be administered. Prior to the experiment, participants will be assessed on whether they have had any previous virtual reality (VR) experience and their level of liking for the foods that will be presented during the experiment (chocolate biscuits and pickles). This assessment will be conducted using a Visual Analogue Scale (VAS) scored on a scale of 0 (do not like at all) to 100 (like very much).

In this study, a within-subjects experimental design will be applied, and participants' food cravings in response to real, virtual, and multisensory (visual, auditory, olfactory, and interactive) food cues will be examined comparatively alongside their physiological (saliva, blood glucose) and neurocognitive (EEG) responses. Each experimental condition will last two minutes, during which EEG recordings will be taken and a total of four saliva samples will be collected from participants every 30 seconds. α-amylase levels will be determined from these samples. Following each condition, the instantaneous food craving level will be assessed using the Visual Analogue Scale (VAS); subsequently, the Excessive Food Craving Scale (EFCS) will be administered at the end of the food conditions.

Participants' body temperatures will be measured three times before, during, and after the experimental process to evaluate the effect of conditions experienced in the virtual reality environment on thermoregulation compared to real-world conditions. Thus, the potential effects of virtual environments on physiological responses, particularly in terms of body temperature, will be analysed comparatively. At the end of the experimental procedure, the Sense of Presence Scale (SPS) will be applied to assess participants' sense of presence in the virtual reality environment.

All data belonging to individuals participating in the study will be analysed using the SPSS 28.0 (Statistical Package for the Social Sciences for Windows) statistical package programme.

This research aims to yield social, academic, and economic benefits. The virtual reality (VR) applications developed within the scope of the project will contribute to improving individuals' quality of life by being used to understand and regulate nutritional behaviours in society. In particular, the development of interactive applications that increase awareness and consciousness regarding healthy eating will play an important role in reducing social problems related to nutrition. Academically, this study will encourage interdisciplinary collaborations (nutrition and dietetics - engineering) by offering methodological and theoretical innovations regarding the use of VR technologies in nutrition science, and will pave the way for the development of multidisciplinary master's theses. Thus, it will contribute to strengthening research capacity and training qualified researchers at national and international levels. Economically, the VR scenarios and measurement methods developed within the scope of the project have commercial application potential in the health technologies, food and nutrition sectors. The commercialisation of these applications will support the development of local software and technologies, enable the formation of new ventures (start-ups/spin-offs) in the health sector, and contribute to increasing competitiveness in the global market.