Poor diets affect more than just our health

By Rachael VorwerkNovember 30th, 2017

The fate of the environment just got personal. It turns out, everyone's waist lines add up and what's better for your health is also better for the environment.
display of confectionary

It’s about more than your waist line.

OUR diets can have severe outcomes on our waistlines – and important impacts on the environment too.

Global food systems cause major impacts on the environment and, as such, changes from the plate up, are being considered internationally as a leading strategy to lessen environmental impact. When the Australian Dietary Guidelines are next reviewed, it is expected to be an important topic.

Australian diet scores 60/100

The 2016 CSIRO Diet survey – Australia’s largest ever diet survey – assesses eating habits in line with the Australian Dietary Guidelines. The higher the score, the healthier the diet.

The Australian diet scored an average of 59/100, says Professor Manny Noakes, co-author on the study.

Discretionary foods mainly encompass foods that we associate with “junk” foods, such as alcohol, chocolate and confectionary, cakes and biscuits, savoury snacks, sugar sweetened beverages, muesli and snack bars, icecream, takeaways, pieces and pastries and processed meat, and fried potato.

According to the Australian Bureau of Statistics, 14-18 year olds reported that more than 40 per cent of their dietary energy was from discretionary foods.

These foods are high in kilojoules, but low or completely lacking in essential nutrients, says Noakes.

“They affect the nation’s growing waistlines and poor health.”

How do poor diets relate to the environment?

The food demand of a growing population places great pressure on the environment. The food system is estimated to account for between 19 per cent and 29 per cent of global greenhouse gas emissions, and around 70 per cent of global freshwater use.

Australia’s overconsumption of discretionary foods is also not good for the planet, and contributes to a major source of greenhouse gas emissions, says CSIRO’s lead author, Dr Bradley Ridoutt.

“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,” says Ridoutt.

“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.”

A gap in literature

Ridoutt and Noakes, together with fellow CSIRO researcher Gilly Hendrie, recently conducted a literature review about dietary strategies that can reduce environmental impact.

“We know a lot about greenhouse gas emissions and diets, but relatively little about other environmental concerns,” says Ridoutt.

“The 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.”

graph with 15 UN development goals

UN Sustainable Development Goals. Image: Wikimedia Commons

GHG emissions are important to consider, no doubt. However, we also need to look beyond GHG 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”, says Ridoutt.

What can Australians 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’.

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 (Department of Environmental and Energy, 2010).

Read more about GHG emissions and the Australian diet.

And to find out more about how your diet stacks up: csiro.dietscore.com.


  1. This is so good to make the analogy between food waste and environmental impact. Having too much on the plate I agree is also a waste.. The notion of your eyes being bigger than your stomach rings true. Just recently I encountered a worm farm that goes under the ground and the worms are free to come and go… the waste we do create can be used this way to keep it out of landfill. Congratualtions a very thought provoking blog…. has nice links too to the movie Just eat it!

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