Plant-based diets and health outcomes in Australia and New Zealand

There is mounting interest in the dual health and environmental benefits of plant-based diets. Such diets prioritise whole foods of plant origin and moderate (though occasionally exclude) animal-sourced foods. However, the evidence base on plant-based diets and health outcomes in Australasia is limited and diverse, making it unsuitable for systematic review. This review aimed to assess the current state of play, identify research gaps and suggest good practice recommendations. The consulted evidence base included key studies on plant-based diets and cardiometabolic health or mortality outcomes in Australian and New Zealand adults. Most studies were observational, conducted in Australia, published within the last decade, and relied on a single dietary assessment about 10–30 years ago. Plant-based diets were often examined using categories of vegetarianism, intake of plant or animal protein, or dietary indices. Health outcomes included mortality, type 2 diabetes and insulin resistance, obesity, CVD and metabolic syndrome. While Australia has an emerging and generally favourable evidence base on plant-based diets and health outcomes, New Zealand’s evidence base is still nascent. The lack of similar studies hinders the ability to judge the overall certainty of evidence, which could otherwise inform public health policies and strategies without relying on international studies with unconfirmed applicability. The proportional role of plant- and animal-sourced foods in healthy, sustainable diets in Australasia is an underexplored research area with potentially far-reaching implications, especially concerning nutrient adequacy and the combined health and environmental impacts.