It wants a focus on diversity in diet, with an emphasis on whole foods and those shown to protect from disease, according to the report, A Future for Food Addressing public health, sustainability and equity from paddock to plate, to be issued today.

Association chief executive officer Michael Moore said food was a critical issue across public health, the environment, social policy and the economy ''and yet we have a fragmented approach''.

''We have a food supply skewed to inappropriate and overly processed foods that are high in sugar, fat and salt; there is inadequate understanding of the environmental impacts of food choices; and we have people struggling to afford healthy food to feed their families,'' he said.

The report said cheaper food tended to be higher in fats, sugars and refined grains, meaning people on lower incomes were more likely to be overweight.

A new national policy should take this into account, as well as the impact on the environment of different foods.

''Food choices have an enormous environmental impact when it comes to carbon dioxide and other greenhouse gas emissions, water usage and land degradation including soil loss and decreasing availability of arable land,'' it said.

''... Every stage of the food chain needs to be considered when assessing the environmental impact of our food choices, including agriculture, manufacturing, refrigeration, transport, packaging, retail, home and waste.''

The report said current dietary guidelines were based on nutrition science, and meant ''staples and whole foods [are] under-emphasised and highly processed foods [are] over-emphasised simply because they meet certain nutrient criteria''.

There was also inadequate consideration of the chronic disease risk of foods, at a time when leading causes of preventable death, such as obesity, heart disease, stroke and Type 2 diabetes, were increasing.