Cooking intervention increases diet quality in adolescents: a randomised controlled trial

Abstract

Background: There is limited evidence to support the direct impact of cooking interventions on diet quality, especially in adolescents. Diet quality can be measured using a Diet Quality Index (DQI). The New Zealand Diet Quality Index-Adolescents (NZDQI-A) is a validated tool used to assess adolescents’ adherence to the national eating guidelines. Objective: To investigate the associations between a cooking intervention and 1) diet quality index; and 2) intake of fruit and vegetable food groups. Design: This thesis reports on the interim analysis of the seven-week follow up of a cooking intervention. This study used a randomised controlled trial time series design. Eighty-four participants (aged 13-15 years old) were allocated to control or intervention groups by block-randomisation. After randomisation, those allocated to the intervention group participated in a one-week intensive cooking program. Questionnaires were completed by participants at baseline, end of intervention and seven-week follow-up. Anthropometry measurements were also taken at baseline and seven-week follow-up. The participants in the intervention then received six take-home food bags, once a week for six weeks. Those allocated to the control group were required to complete questionnaires and anthropometry at the same point as the intervention group. The New Zealand Adolescent Food Frequency Questionnaire (NZAFFQ) was used to calculate The New Zealand Diet Quality Index-Adolescents (NZDQI-A). Effects of intervention on DQI and fruit and vegetable subscales were estimated using linear regression adjusted for baseline. Results: Interim analysis of the seven-week follow-up data in 84 participants (intervention = 66, control =18) showed the difference in the magnitude of change in DQI scores between the two groups between baseline and follow up is 7.7 in favour of the intervention group. Sub scores of fruit and vegetables (FV) also significantly increased by 3 and 2.6 points respectively. Further breakdown of intervention FV scores showed improvement in adequacy category as 58.8% of the intervention participants moved up a category of fruit intake and 42.9% for vegetable adequacy made the same shift up a category. Group interview feedback reported general positive reflections on grocery shopping, making a meal for their family members, learning new skills, meeting new people and enjoyment of cooking and eating. Conclusion: Participation in a cooking intervention increased total DQI and sub-scale fruit and vegetable groups. Cooking also increased adequacy of intake of both fruit and vegetables. Participants generally enjoyed and requested similar programs to be run in the future.