Modelled health impacts of three stakeholder-selected policies to support healthy and environmentally sustainable population diets in New Zealand

• Uses rich qualitative data on stakeholder perspectives to inform policy design. • Presents three food policies of varying designs to inform real world policy. • Identifies cost saving policies which could potentially reduce health inequities. • Policies require large up-front costs or loss of governmental income. • Health system cost savings are expected in the medium to long term. Food production and consumption impacts both planetary and population health. This research aimed to estimate the impacts of three food policies, selected by stakeholders, for the New Zealand (NZ) population: Exempting core, sustainable foods from Goods and Services Tax (GST), education about healthy sustainable foods and māra kai (food garden informed by mātauranga Māori) and community gardens. These were modelled using a proportional multistate lifetable model through to health gains (in Health Adjusted Life Years, HALYs), health equity impacts, and net costs (combining health system costs/cost savings and intervention costs in 2011 NZD). Changes in dietary intake were modelled through to changes in diet related disease incidence over the remaining life of the 2011 NZ population (n = 4.4 million, 3% discounted). Exempting core, sustainable foods from GST resulted in 87,410 HALYs (95% Uncertainty Interval (UI): 72,280 to 104,110) and health system cost savings of $927.3 Million (M), UI: (686.6 to 1216.6 M). Education about healthy sustainable foods generated small health impacts (1,170 HALYs, UI: 930 to 1,430) and health system cost savings ($9.6 M, UI: $6.8 to $12.9 M). Māra kai and community gardens generated 8,040 HALYs (UI: 4,720 to 11,800) and would cost the government $364.3 M (UI: $267.6 to $464.6 M). All scenarios produced more age-standardised per capita health gain for Māori (Indigenous population) than non-Māori. The first two policies were cost saving while the māra kai and community gardens policy was borderline cost-effective. This research shows that these policies have the potential to improve population health and could be used to inform food policy in high-income countries. For NZ, these policies could also reduce ethnic health inequities; careful policy design involving relevant stakeholders, including Māori communities, is needed to ensure health and equity benefits are realised.