The long term effect of the Create Our Own Kai intervention on diet quality amongst New Zealand adolescents

Background: A high consumption of convenience and take-away foods are thought to be a major contributor to obesity amongst New Zealand adolescents. Additionally, due to changes within the New Zealand school curriculum, adolescents may be missing the opportunity to learn how to cook. Foods cooked from scratch are generally healthier, containing more vitamins and fibre and less saturated fat, salt and sugar. Cooking interventions in the northern hemisphere have shown that they can increase fruit and vegetable consumption in the shortterm. However, no study has looked at the long term effects a cooking intervention has on overall diet quality and Body Mass Index (BMI) within adolescents. Objective: To investigate the long-term effects of a cooking intervention on diet quality in New Zealand adolescents. Design: The study used a randomised controlled trial time series design. Participants were randomly allocated by block randomisation to either the control or the intervention group, with a total of 118 participants completing the full study. Questionnaires and anthropometric measurements were completed by participants at baseline, end of intervention, seven-week follow-up and 12-months follow up. Participants in the intervention group completed a oneweek cooking program (COOK week) followed by the support phase, which supplied meal kits, one weekly for six weeks. The New Zealand Adolescent Food Frequency Questionnaire (NZAFFQ) was used to calculate The New Zealand Diet Quality Index-Adolescents (NZDQI-A). Effects of the intervention on Diet Quality Index (DQI) and fruit and vegetable subscales were estimated using linear regression adjusted for baseline values. Results: After seven weeks the change in DQI score was significantly greater in the intervention compared to the control group. At 12 months follow up the intervention group still scored an average total DQI score of four points higher than the control group, but this was not statistically significant. Changes for the ‘fruits’ and ‘vegetables’ sub scores from baseline to the seven week follow up was significantly different between the intervention and control group. These changes were not maintained at the 12 month follow up. There were no changes observed in BMI for either group at 12 month follow up. Conclusion: Participants in the intervention group showed significant improvements in diet quality and fruit and vegetable intake for the duration of the intervention, this was not maintained after 12 months