Environmental impacts of diets high in beef and lamb
Methane is the biggest contributor to carbon dioxide equivalent emissions in Australia, and has a significant impact on Australia’s greenhouse gas emissions. The evidence is strong and clear on the negative impact of ruminant animals on the environment. Beef and lamb have the highest greenhouse gas emissions and land use per 100 grams of protein than any food. Therefore, reducing your intake of beef and lamb will result in decreasing the climate impact of your diet.
In Australia, the greenhouse gas emissions related to the production of beef is mainly from methane that is produced during the digestion of grass (via enteric fermentation), followed by the greenhouse gas emissions from manure and pasture management. This varies from many other countries, whereby a greater contributor to overall emissions of cattle is related to concentrated feeds (including the land used to create the feed), housing and pasture management.
International studies on the global warming potential of ruminant animals found beef and lamb have a similar impact. In Australia, some evidence suggests lot-fed beef is more favourable over grass-fed cattle due to the lower greenhouse gas emissions associated with this production method.
Who can help to make a difference?
As well as individuals reducing their dietary intake of ruminant animals to reduce environmental impact, modifying farming practices (such as changing feeds) can also reduce the levels of methane produced during enteric fermentation. To support farmers to make such changes, the government must assist them through policies and initiatives, and we can all support them by buying from local, Aussie farmers who are making these conscious changes.
Considering most Australian’s eat excessive amounts of red meat, reducing the amount we consume can have significant benefits in the long term. In fact, the leading international experts at the EAT Lancet Commission recommends that in order for the world to feed 10 billion by 2050, from a population level point of view we should all be reducing our red meat intake (beef, lamb and pork) to around 100g per week. As such, we all play a role in reducing the global warming potential of ruminant animals, whether it be making a change to the food we buy and eat, supporting farmers in other ways or advocating for government policies.
*estimates vary from 28-100 times the global warming potential compared to carbon dioxide.
Health impacts of diets high in beef and lamb
Eating beef and lamb provides a rich food source of protein, iron, zinc, vitamin B12 and other essential nutrients. But the health impacts aren’t all positive with scientific evidence suggesting there are health benefits with reducing red meat intake.
The World Cancer Research Fund highlights the greater the amount of red meat consumed, the higher the risk of some cancers, with strong scientific evidence finding red met increases risk of colorectal (bowel) cancer. This is supported by the Australian Dietary Guidelines that state the consumption of more than 100-120 grams of red meat per day increases risk of colorectal cancer. An international meta-analysis (a review of other studies) found red meat intake was associated with mortality related to cardiovascular disease.
How much is too much?
According to the Dietary Guidelines (published almost a decade ago in 2013), one serve of lean red meat is equivalent to 65 grams cooked weight, and Australian’s should aim to eat a maximum of 455g of red meat per week for health reasons. Lean red meat is recommended due to its high saturated fat content and it's impact on heart health.
The International EAT-Lancet commission into healthy and environmentally sustainable diets (published in 2019) recommended a maximum of 28 grams of either beef, lamb or pork daily (or on average 100g per week), for health and environmental reasons.
If eaten in small amounts, lean red meat can be a good source of essential vitamins, minerals and protein. However, it does not need to be the hero of a dish, rather a condiment eaten occasionally.