Exploring the Use of Genetic and Behavioural Data in Tailoring Dietary and Lifestyle Support

Exploring the Use of Genetic and Behavioural Data in Tailoring Dietary and Lifestyle Support: An n=1 Randomised Trial

Personalised nutrition approaches typically rely on static information such as health status, lifestyle and genetic data. However, adherence often remains low because daily behaviours are influenced by psychological states, motivation and real-time barriers. There is growing interest in whether integrating behavioural signals and timely prompts could strengthen engagement. The purpose of this study is to explore whether incorporating psychological adaptation and just-in-time behavioural prompts leads to better adherence to a personalised nutrition programme compared with commonly used personalised approach (combining health, lifestyle and genetics data without psycho-behavioural adaptation). Using a six-week n-of-1 randomised trial design implemented across multiple participants, the research will also assess the feasibility of delivering this adaptive support in a free-living environment, as well as participants' engagement, acceptability and perceived usefulness. Following completion of the 6-week intervention, an optional focus group will be conducted with a subset of participants (maximum 8) within four weeks of the final study day. The focus group will last approximately 60-90 minutes and will be conducted in person or via video call. Qualitative data from the focus group will be analysed using reflexive thematic analysis (Braun & Clarke, 2021). These findings will inform the development of an adaptive personalised nutrition AI agent.

Inclusion Criteria:

• Participants must:

  1. Be 18-45 years old.
  2. Have a BMI between 18.5 and 40 kg/m² (normal weight to obesity categories).
  3. Own a smartphone with WhatsApp installed.
  4. Be willing to receive daily messages for 6 weeks.
  5. Be able to provide informed consent.
  6. Be willing to provide a cheek swab for DNA analysis.
  7. Have sufficient English proficiency to understand daily written instructions.

Given that the programme focuses on the six pillars of lifestyle medicine (nutrition, physical activity, sleep, stress management, social connection, and alcohol/substance moderation), participants must be able to safely engage with light lifestyle recommendations.

Exclusion Criteria:

• Participants will be excluded if they:

  1. Have a diagnosed eating disorder or significant disordered eating symptoms.
  2. Are currently pregnant or breastfeeding.
  3. Have any medical condition requiring medically supervised dietary modification (e.g., diabetes requiring medication, kidney disease, coeliac disease).
  4. Are currently taking medication that significantly affects appetite, weight, or metabolism (e.g., GLP-1 agonists).
  5. Work night shifts
  6. Have severe mental health conditions (e.g., moderate-severe depression, psychosis).
  7. Are participating in another behaviour-change or weight-related study.
  8. Are unwilling to receive WhatsApp messages
  9. Are unwilling to receive genetic information This will be checked with PARQ questionnaire

Focus group participants:

All 14 study participants will be invited to participate in the optional post-intervention focus group. As the focus group is limited to a maximum of 8 participants, if more than 8 express interest, selection will be made to ensure diversity across gender, age, engagement during the intervention and personality profile to maximise the richness of discussion. Participants who are not selected or who decline will not be disadvantaged in any way and their study data will be retained and analysed as normal.