We know a poor diet can have severe outcomes on our waistline but they can also have important impacts on the environment too.
Poor diets affect more than just our health
Australian's poor diets are growing the nation's waistlines and contributing to health issues but global food systems cause major impacts on the environment as well. Changes from the plate up, are being considered internationally as a leading strategy to lessen environmental impact.
Discretionary or 'junk' foods, such as alcohol, confectionery, fried foods and processed meat are high in kilojoules but low or completely lacking in essential nutrients. Australia's overconsumption of discretionary foods is not good for the planet, and contributes to a major source of greenhouse gas emissions.
The food demand of a growing population places great pressure on the environment. The food system is estimated to account for between 19 and 29 per cent of global greenhouse gas emissions, and around 70 per cent of global freshwater use.
Emissions from discretionary foods are considered avoidable because they are not a necessary part of a balanced diet. However, just cutting out discretionary food would leave many diets energy deficient. Australians generally need to reduce their intake of discretionary foods and increase core foods. Eating according to dietary guidelines will help to reduce population dietary greenhouse gas emissions.
Plugging a research gap
Our Nutrition and Health and Agriculture and Food teams together conducted a literature review of dietary strategies that can reduce environmental impact.
The United Nations' Sustainable Development Goals mention 14 discrete environmental concerns that need to be addressed. As an example, of the 93 journal articles addressing environmental assessment of diets, only one study assessed data in relation to fish stocks.
Greenhouse gas emissions are important to consider but we also need to look beyond emissions because it is well known that efforts to reduce one environmental impact can very often exacerbate others. Current research on environmental impact lacks a holistic view. Our team of researchers have looked beyond just greenhouse gas emissions, to the impact on scarce water resources and cropland. We have consistently found that eating to meet your needs and reducing unhealthy 'junk' foods would have the largest impact on reducing Australian's dietary environmental footprint.
What can we do to work towards a low-environmental diet?
Although more research is needed about low-environmental diets in Australia, the researchers recommend three ways to reduce your diet's environmental impact:
- Know your serving size and stick to it
Over-eating is a form of food waste. Data suggests that greenhouse gas emissions are positively correlated with total energy intake – that is, the larger the portion size, the higher the greenhouse gas emissions. The super-sizing phenomena has considerably impacted the environmental footprint and doesn't do any good for your body, or the environment. It's time to re-think the value and amount of resources that go into our food.
- Eat according to your needs
Another key recommendation is to eat according to the Australian Dietary Guidelines. This means discretionary food intake is reduced to ensure adequate nutrients by increasing core foods. This addresses excess energy and food overconsumption. A nice tagline is to 'eat to your needs'. Try the CSIRO Healthy Diet Score to see how your diet habits measure up against the Australian Dietary Guidelines.
- Reduce food waste and only buy as many groceries as you need
Although it isn't a dietary strategy, reducing food waste is an immediate way to ensure we aren't wasting resources. Some handy tips are to plan your meals, and use a shopping list when going to the supermarket. Food wastage directly relates to environmental impact because of the amount of energy and resources that are needed to go into making that piece of food. In Australia alone, it's estimated that food makes up 35 per cent of household and council waste