The OPTIMISE Intervention for Reducing Meat Consumption in UK Adult Meat-eaters

Effectiveness of an Online Programme to Tackle Individual's Meat Intake Through SElf-regulation (OPTIMISE): A Randomised Controlled Trial

This randomised controlled trial will test the effectiveness of a self-regulation intervention for reducing meat consumption in people who are motivated to change their meat-eating habits.

An individually randomised, two-arm, parallel-group design will be employed, assessing superiority of the self-regulation intervention over a control. The intervention aims to support individuals in self-monitoring their meat consumption, learning about the impact of their food choices on their health and the environment and setting personal meat reduction goals as well as implementing those goals to reduce meat consumption in manageable steps.

After a baseline week of self-monitoring meat consumption, the intervention will be delivered over four weeks, followed by a four-week long maintenance phase.The study will be delivered remotely through our bespoke website developed specifically for the intervention.

All participants will complete a baseline questionnaire that asks about their demographic characteristics, assesses their self-efficacy regarding consumption of meat-free dishes and asks about their meat-eating identity. Participants will be then randomised 1:1 to the control or intervention group. During the baseline week (week 1, days 2-5), participants will be invited to complete a meat frequency questionnaire, daily, each time looking back at the previous day. After the baseline week, participants will follow their assigned condition for eight weeks. In the control condition, participants will be asked to try and reduce their meat intake, without further guidance. In the intervention condition, participants will be guided through an experimentation process for the first four weeks. This includes setting a meat reduction goal, tracking meat intake daily, planning and implementing an action to reduce meat intake daily and evaluating those actions weekly. After these four weeks (weeks 2-5), intervention group participants will enter a four-week long maintenance phase during which they will be asked to continue with the actions they found useful in the previous weeks. During the fifth and ninth weeks, all participants will be invited to complete the meat frequency questionnaire daily. On the last day of both the fifth and ninth weeks, participants will be asked to complete the self-efficacy and meat-identity questionnaires used in the baseline session again. On the last day of the fifth-week participants of the intervention condition will be further asked to complete a questionnaire to evaluate the intervention. On the last day of the ninth-week participants of the control condition will be asked what kinds of strategies they used to actively reduce their meat intake in the last eight weeks.

Inclusion Criteria:

• Be willing and able to give informed consent
• Be resident in the UK
• Self report to speak English fluently
• Self-report to eat meat at least five times per week
• Be willing to reduce their meat intake
• Have access to devices compatible with the delivery format of the intervention

Exclusion Criteria:

• Enrolled in another dietary intervention study
• Trying to lose weight