AimsTo test if a New Zealand food–based Mediterranean diet (NZMedDiet) with behavioural intervention improves cardiometabolic health and wellbeing.MethodsA randomised controlled trial comparing 12 weeks of the NZMedDiet to usual diet in participants with increased cardiometabolic risk (metabolic syndrome severity score [MetSSS] > 0.35). The intervention group was provided with food and recipes to meet 75% of their energy requirements, supported by a behavioural intervention to improve adherence. The primary outcome measure was (MetSSS) after 12 weeks.ResultsTwo hundred individuals with mean (SD) age 49.9 (10.9) years of which 62% women were enrolled with their household/whānau. After 12 weeks, the mean (SD) MetSSS was 1.0 (0.7) in the control (n = 98) and 0.8 (0.5) in the intervention (n = 102) group; estimated difference (95% confidence interval [CI]) of −0.05 (−0.16 to 0.06), p = 0.35. The Mediterranean diet score (PyrMDS) was greater in the intervention group 1.6 (1.1–2.1), p < 0.001, consistent with a change to a more Mediterranean dietary pattern. Weight reduced in the NZMedDiet group compared with control (−1.9 kg [−2.0 to −0.34]), p = 0.006 and wellbeing, assessed by the SF‐36 quality of life questionnaire, and improved across all domains. For example, the physical component summary score difference (95% CI) was 4.0 (2.4–5.7), p < 0.001, and the mental component summary score difference was 3.0 (0.7–5.2), p = 0.01.ConclusionIn participants with increased cardiometabolic risk, food provision with a Mediterranean dietary pattern and a behavioural intervention did not improve metabolic risk scores but was associated with reduced weight and improved quality of life.