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Completed

NCT Number: NCT04961216

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

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.

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Key information

Conditions

Diet Habit Behavior Behavior, Animal Feeding Behavior Self-Control Social Behavior

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Nuffield Department of Primary Care Health Sciences, University of Oxford

Oxford, OX2 6GG, United Kingdom

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

OPTIMISE

Behavioral

Self-regulation intervention

Primary outcomes

  1. Change in mean daily meat consumption from baseline to follow-up 1, comparing intervention and control groups.

    Time frame: five weeks

    Meat consumption was measured with meat-frequency questionnaires administered daily during the baseline week and follow-up 1.

Secondary outcomes

  1. Change in mean daily meat consumption from baseline to follow-up 2, comparing intervention and control groups.

    Time frame: nine weeks

    Meat consumption was measured with meat-frequency questionnaires administered daily during the baseline week and follow-up 2.

  2. Change in mean daily meat consumption from follow-up 1 to follow-up 2, comparing intervention and control groups.

    Time frame: nine weeks

    Meat consumption was measured with meat-frequency questionnaires administered daily during follow-up 1 and follow-up 2.

  3. Change in mean daily consumption of meat subgroups from baseline to both follow-ups, comparing intervention and control groups.

    Time frame: five and nine weeks

    Meat subgroups assessed: red meat, processed meat, and red & processed meat.

  4. Change in meat-free self-efficacy from baseline to both follow-ups, comparing intervention and control groups.

    Time frame: five and nine weeks

    Self-efficacy was measured using three items from the self-efficacy scale Lacroix & Gifford (2019):

    "I lack the cooking skills to prepare meat-free meals" "I don't know what to eat instead of meat" "I don't have enough willpower to not eat meat"

    Answers were given on a 7-point Likert scale ranging from (1) "strongly disagree" to 7 "strongly agree".

  5. Change in participants meat-eating identity from baseline to both follow-ups, comparing intervention and control groups.

    Time frame: five and nine weeks

    Meat identity questionnaire was used to categorise people as follows: 1) meat-eating identity, 2) reduced meat-eating identity, and 3) non-meat eating identity.

    Participants who moved from 1 to 2, 1 to 3, or 2 to 3 were coded as positive meat-identity change=1 and other changes/no change were coded as positive meat-identity change=0

  6. Comparison of actions taken by the control group participants and those taken by the intervention group.

    Time frame: nine weeks

    Control group participants completed a questionnaire at follow-up 2 which asked what strategies they had tried to reduce their meat consumption. Reponses were free-text and explored qualitatively. We assessed which meat reduction actions were chosen by our intervention group participants and compared these to those reported by the control group.

  7. Acceptability of the self-regulation intervention for reducing meat consumption

    Time frame: five weeks

    Acceptability was assessed with an intervention evaluation questionnaire administered at follow-up 1 to intervention group participants.

    The questionnaire asked participants to rate the usefulness of individual intervention components (tracking meat consumption daily, health/environmental feedback, action planning) and additional resources (weekly action evaluation, downloadable action diary, downloadable action overview, links to other resources, ability to review your journey) on a scale of 1 (not useful) to 10 (very useful). We also asked if participants had any additional feedback - this was a free-text question and responses were coded and analysed qualitatively.

  8. Percentage of meat frequency questionnaires completed by participants

    Time frame: nine weeks

    Intervention group participants could complete a maximum of 42 meat frequency questionnaires (daily weeks 1-5 and 9) over the study period, while control group participants could complete a maximum of 21 meat frequency questionnaires (daily weeks 1, 5 and 9). For each participant we calculated their percentage of meat frequency questionnaires submitted (i.e. X/42* 100 or X/21* 100).

    We then looked at the percentage of participants who completed all sessions, and at least 80% of sessions, in both groups.

Other outcomes

  1. Outlier sensitivity analysis of primary outcome

    Time frame: five weeks

    We ran a sensitivity analysis repeating the primary analysis (change in mean daily meat consumption from baseline to follow-up 1) excluding days in which participant total meat intake exceeded 1.5 kg (measured by the meat frequency questionnaires) to assess the effect of outliers.

  2. Barriers to adherence to meat reduction actions

    Time frame: five weeks

    Barriers were identified by open-text responses to daily (Weeks 2-5) action completion question when participants indicated they didn't stick to their action: "Please tell us a little bit more about why you were unable to stick to the action you had planned."

Sponsors and collaborators

Lead sponsor

University of Oxford

Other

Registry information

Official study title

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

Acronym: OPTIMISE

Important dates

Study start
2021
Primary completion
2021
Study completion
2021
First posted
Jul 14, 2021
Registry last updated
Jul 14, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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