Can recipe-boxes help families eat healthier? A pilot trial in households with children in Birmingham
| ISRCTN | ISRCTN45164711 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN45164711 |
| Secondary identifying numbers | G122382 |
- Submission date
- 23/06/2025
- Registration date
- 24/06/2025
- Last edited
- 17/07/2025
- Recruitment status
- Recruiting
- Overall study status
- Ongoing
- Condition category
- Other
Plain English summary of protocol
Background and study aims
A higher proportion of energy intake from home-prepared food and a greater frequency of home-prepared meals are associated with higher dietary quality. Recipe boxes are one intervention that may enable households to prepare and eat healthy meals at home. Qualitative research points to a range of promising benefits, including improved confidence in cooking, greater perceived meal healthiness, and reduced take-out. However, it remains unclear whether recipe-box interventions can improve dietary quality, are feasible and acceptable across the population, and can improve users' capabilities to prepare food that they value. This study will help to address these questions by conducting a randomised pilot and feasibility study (PFS), partnering with a commercial recipe-box company.
Who can participate?
Households with children of primary and secondary school age in the city of Birmingham and the surrounding area.
What does the study involve?
Households will be invited to take part in this study via five recruitment channels: social media, referrals from friends and customers of the recipe-box company, employers, schools, and community organisations. The study aims to randomly allocate approximately 150 consented households. Interested participants will complete an eligibility screening form online and will then be sent the Participant Information Sheet and Consent Form. Once consented, participants will be asked to complete two dietary recalls using the Intake 24 platform and online questionnaires. Participants will then be allocated to either the intervention group or the control group. The intervention group will be offered a 6-week recipe-box subscription discounted by 60% in week 1 and 50% in weeks 2 to 6, and the choice to continue for a further 4 weeks at a discount of 20%. The waitlist control group will receive an offer for the same discounted subscriptions 10 weeks after randomisation. Participants will be asked to complete the same online questionnaires and dietary recalls at 6 weeks and 10 weeks after baseline. A sample of participants from both the intervention and control groups will be invited to complete qualitative interviews at baseline and 6 weeks.
What are the possible benefits and risks of participating?
Participants in the intervention group will receive discounts for the recipe-box subscription for 10 weeks, and the control group participants will receive the same discount after the 10-week study period. Participants will also receive up to £75 for completing surveys at baseline, week 6, and week 10, and (if invited) an additional £25 for an interview. Participants in the intervention group will need to pay for part of the cost of the recipe boxes and invest time in completing surveys and interviews.
Where is the study run from?
University of Cambridge, School of Clinical Medicine, UK
When is the study starting and how long is it expected to run for?
October 2024 to October 2025
Who is funding the study?
Economic and Social Research Council (ESRC), UK
UK Research and Innovation (UKRI), UK
Who is the main contact?
Mr Noah Cooke, ncac3@cam.ac.uk
Contact information
Principal Investigator
MRC Epidemiology Unit, Level 3 Institute of Metabolic Science, University of Cambridge, School of Clinical Medicine
Cambridge
CB2 0SL
United Kingdom
 ORCID ID |
0000-0002-1861-6757 |
|---|---|
| Phone | +44 (0)1223769159 |
| martin.white@mrc-epid.cam.ac.uk |
Public, Scientific
MRC Epidemiology Unit, Level 3 Institute of Metabolic Science, University of Cambridge, School of Clinical Medicine
Cambridge
CB2 0SL
United Kingdom
| ORCID ID |
0000-0002-7448-9297 |
|---|---|
| Phone | +44 (0)1223 769200 |
| noah.cooke@mrc-epid.cam.ac.uk |
Study information
| Study design | Parallel unblinded randomized pilot and feasibility trial |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised parallel trial |
| Study setting(s) | Home, Retail/food outlet |
| Study type | Prevention, Quality of life |
| Participant information sheet | Not available in web format, please use contact details to request a participant information sheet |
| Scientific title | Exploring the impact of recipe-boxes on dietary quality and food agency: a pilot RCT in households with school-aged children |
| Study acronym | TRILOGY |
| Study objectives | 1. The recruitment strategies and enrolment procedures will be acceptable and feasible to participants, as assessed from sample size attained, recruitment rate, and semi-structured interviews. 2. The discounted recipe-box subscription will be acceptable and feasible to participants, from the retention rate, recipe box ordering rate, and semi-structured interviews. 3. Allocation to the waitlist control group will be acceptable and feasible, from the retention rate and from semi-structured interviews. 4. The level of adherence to allocation in the waitlist control group will be high (>90%) from questionnaires and semi-structured interviews. 5. The implementation of trial procedures will be of high fidelity 6. The regular use of recipe boxes in the intervention group will improve participants’ food agency, from semi-structured interviews 7. The regular use of recipe boxes in the intervention group will lead to intermediaries in our Theory of Change 8. The regular use of recipe boxes in the intervention group will lead to benefits in our Theory of Change, but also encounter barriers in our Theory of Change. |
| Ethics approval(s) |
Approved 24/03/2025, University of Cambridge, School of Humanities and Social Sciences Research Ethics Committee (17 Mill Lane, Cambridge, CB2 1RX, United Kingdom; +44 (0)1223 766238; hssrec@admin.cam.ac.uk), ref: 25.397 |
| Health condition(s) or problem(s) studied | Promotion of improved dietary quality, food and cooking skills, food agency, and capability wellbeing. Prevention of diet-related diseases (in general). |
| Intervention | This study is a parallel, unblinded, randomised pilot and feasibility trial, with 1:1 allocation between an intervention group receiving discounted recipe box subscriptions and a waitlist control group receiving the recipe-box subscriptions after the trial ends. The study will use stratified randomisation using one stratum defined by the ethnicity of the primary food provider. Ethnicity was chosen because it has the potential to be an effect modifier based on the literature for similar dietary public health interventions. With one stratification variable, there will be 2 strata; a separate randomisation list will be generated for each stratum with a block size of 4, using Stata statistical software, and incorporated into the study database prior to the start of the study. The intervention group will receive a discount for a recipe-box subscription from a commercial recipe-box company: 60% off the first week (first recipe box) and 50% off for 5 subsequent weeks (five recipe boxes), not including the delivery fee, with the option to continue at 20% off for another 4 weeks. The discounts will apply to up to 5 recipes per household per week, with a maximum of 5 portions per box and 20 portions total per week, for 10 weeks, with the freedom to choose any meals available on the company website. However, participants ordering 5 portions per recipe will only be able to order a maximum of 3 recipes, due to the size of the recipe box. Note that the structure of the company's pricing means that the cost per portion (with or without the discount) decreases if more recipes and portions are ordered. From data shared by the recipe- box company on average prices, the average cost over the first 6 weeks is expected to be as follows: for 4 meals for a family of 4 will cost around £28.70 per week (£1.79 per portion); for 4 meals for a family of 3 will cost around £27.49 per week (£2.29 per portion); for 4 meals for a family of 2 will cost around £20.72 per week (£2.59 per portion); for larger families, 3 meals for 5 people will cost around £30.75 per week (£2.05 per portion). Participants will register as customers on the company's website and input their trial code to receive their discount. Participants will be able to select any meals on the menu for that week, including “upgrades” and “sides” (which will not be discounted) and can choose between one and five portions per meal. After the first box, delivery will cost £3.99 per recipe box at purchase (not discounted). Households can order two or more recipes per week. The intervention “dose” in this free-living sample cannot easily be standardised. Similarly, participants cannot be prevented from ordering additional recipe boxes without a discount, although this is considered to be unlikely given the intensity of the subscription. Participants will be charged weekly and can elect to skip weeks, pause or cancel at any time. Participants will be asked to order on the company's website. Participants’ “ordering deadline” will be participant-specific: the day of the week and time they placed their first recipe-box order, 3 days before delivery. Note that participants will be able to change their delivery day before their ordering deadline. Participants will receive the same weekly reminders to order that regular customers receive. Participants can see menus and order up to three weeks in advance and edit orders up to three days before the scheduled delivery day. As per the company's standard procedures, if participants miss their ordering deadline, and do not cancel their subscriptions or elect to skip the next week, recipes will automatically be selected (based on what the recipe-box company predicts they would enjoy) and delivered at the discounted price (and the participant will be charged). However, at the end of the 6-week discount, the subscription will not automatically continue. To continue ordering at a 20% discount for another 4 weeks, participants will either need to 1) opt in to an invitation sent 3 weeks into the trial, or 2) continue ordering after their subscription is forcefully paused after 6 weeks. The recipe-box company will share data on orders from the account associated with the discount code if the participant consents for the company to do so. |
| Intervention type | Other |
| Primary outcome measure | 1. Acceptability of the recruitment strategies and enrolment procedures measured from the sample size attained at enrolment 2. Acceptability of the recipe-box subscription at the discounted rate measured from the retention rate at week 6 3. Acceptability of allocation to the waitlist control measured from the retention rate at week 6 4. Sample size needed for the main trial to detect an average treatment effect in the primary outcome in the main trial (dietary quality) at week 6 with α of 0.05 and power of 0.90 |
| Secondary outcome measures | Qualitative 1. Perceived benefits of the recipe-box subscription and barriers to participation in the intervention group measured from semi-structured interviews at week 6. 2. Presence of hypothesised mediators in the Theory of Change measured from semi-structured interviews in the intervention group at week 6 3. Changes in participants’ food agency, from questionnaires, as well as semi-structured interviews, at week 6 Acceptability 4. Acceptability of the recruitment strategies and enrolment procedures measured from the recruitment rate at enrolment and semi-structured interviews at baseline 6. Acceptability of the recipe-box subscription at the discounted rate measured from the retention rate at week 6, recipe-box ordering rate from weeks 1 to 6, and from semi-structured interviews at week 6 7. Acceptability of allocation to the waitlist control group measured from retention rate and semi-structured interviews, at week 6 Feasibility 8. Feasibility of the recruitment strategies and enrolment procedures measured from recruitment rate (pre-enrolment), sample size attained at enrolment, and semi-structured interviews at baseline 9. Level of adherence to allocation in the intervention group: ordering 2 to 5 recipes weekly from weeks 1 to 6 10. Level of adherence to allocation in the waitlist control group, not obtaining recipe boxes from any sources from baseline to week 10 11. Fidelity of implementation of trial procedures (e.g. execution of the social media campaigns; digital and in-person recruitment procedures; recruitment through the company's existing customers; notifications and follow-up by study team) |
| Overall study start date | 01/10/2024 |
| Completion date | 01/10/2025 |
Eligibility
| Participant type(s) | Healthy volunteer |
|---|---|
| Age group | Mixed |
| Lower age limit | 18 Years |
| Upper age limit | 130 Years |
| Sex | Both |
| Target number of participants | n = 150 randomised participants |
| Key inclusion criteria | 1. Having at least one child attending primary or secondary school in the household. 2. Having access to cooking rings, an oven, and a fridge at home (without which these participants could not prepare Gousto’s recipes). |
| Key exclusion criteria | 1. Have used recipe boxes in the previous 3 months. 2. The main food provider (who will complete the questionnaires) cannot read, write, or speak English. 3. Not having access to the internet and a digital device (smartphone, tablet, or laptop). 4. Any member of the household having recently participated (past 3 months), currently participating, or scheduled to participate, in another diet-related trial, cohort, or clinical study. |
| Date of first enrolment | 27/04/2025 |
| Date of final enrolment | 21/07/2025 |
Locations
Countries of recruitment
- England
- United Kingdom
Study participating centre
University of Cambridge School of Clinical Medicine
Box 285 Institute of Metabolic Science
Cambridge Biomedical Campus
Cambridge
CB2 0QQ
United Kingdom
Sponsor information
University/education
The Old Schools, Trinity Lane
Cambridge
CB2 1TN
England
United Kingdom
| Phone | +44 (0)1223 333543 |
|---|---|
| croenquiries@admin.cam.ac.uk | |
| Website | https://www.research-operations.admin.cam.ac.uk/ |
"ROR" |
https://ror.org/03n0ht308 |
Funders
Funder type
Government
Government organisation / National government
- Alternative name(s)
- ESRC
- Location
- United Kingdom
Government organisation / National government
- Alternative name(s)
- UKRI
- Location
- United Kingdom
Results and Publications
| Intention to publish date | 01/01/2026 |
|---|---|
| Individual participant data (IPD) Intention to share | Yes |
| IPD sharing plan summary | Available on request |
| Publication and dissemination plan | Planned publications in peer reviewed journals. Separate publications for 1) quantitative outcomes acceptability, and feasibility, and 2) qualitative findings, including food agency. |
| IPD sharing plan | Data generated and/or analysed directly by the research team (e.g. data from dietary recalls and other surveys) during the current study will be available upon request from Professor Martin White, University of Cambridge (martin.white@mrc-epid.cam.ac.uk). These requests will be reviewed by the Principal Investigators for scientific merit and integrity before release, in line with the MRC Epidemiology Unit's Data Sharing Policy. Shared datasets will be anonymised. Participants will have consented for anonymised data to be shared. The datasets generated by the recipe box company (e.g. on what recipes participants ordered) during and/or analysed during the current study will not be available due to commercial sensitivity. |
Editorial Notes
17/07/2025: The date of final enrolment was changed from 16/07/2025 to 21/07/2025.
11/07/2025: The date of final enrolment was changed from 01/07/2025 to 16/07/2025.
23/06/2025: Study's existence confirmed by the University of Cambridge, School of Humanities and Social Sciences Research Ethics Committee.
