Watch what you’re cooking – it may turn out to be our planet on your cooktop!

No recipe lists Planet Earth as an ingredient. Yet every human activity has an equivalent carbon footprint and that includes the food you eat. An activities carbon footprint is based on the greenhouse gas emissions generated to produce, create or do that activity. Your car, fuel, heating system in your home, or method of cooking, among other things, impact the environment. But it’s not only products that have gone through the manufacturing process that produce greenhouse gas emissions, fresh foods do too.

A recent study led by Dr. Stephen Clune of the University of Lancaster, UK and his colleagues from RMIT, Melbourne, Australia, measured the carbon cost and global warming potential of each food item.

Eating is as necessary as breathing. So, imagine the impact to the environment, if there is a collective and conscious effort to make such a change, not to mention a healthier population.

Researchers were able to establish a data set that lists fresh food items in terms of global warming potential values. Plant sourced foods such as vegetables, fruits, and grains were found to have the lowest impact. Nuts and pulses follow closely. Meats from non-ruminant animals such as chicken and pork, and most fish have medium impact. Meats from ruminant (multiple-gut) animals like beef and lamb have the highest impact.

In essence, the data will help consumers as well as food service industries compute and plan their menu by choosing dishes that would register a lower, if not the lowest possible carbon cost.

Of course, not all high impact foods can be substituted with those with the lowest impact. That would be like substituting lamb with apples or lentils just to make the values add up to an acceptable carbon cost. But you can substitute it with chicken or pork since they have lower carbon cost compared to lamb.

The carbon cost of each food item is measured in terms of greenhouse gas emission. These are the foods you can buy per kilo of greenhouse gas emission:

  • 5.8 kg of onions – approximately 50 medium onions
  • 3.5 kg of apples – approximately 20 medium apples
  • 2.6 kg oats
  • 1 kg lentils
  • 0.8 litres milk
  • 290 g salmon
  • 290 g eggs – approximately 5 small eggs
  • 270 g chicken
  • 40 g UK beef or lamb

Translated in another way, it means that when you eat say, 390g of lamb, it’s carbon cost is the same as driving 90 miles. When it comes to pork, more than half the emissions come from raising the animals. If you’re really a meat eater, chicken is a good compromise as it produces the least greenhouse gas emissions compared to most meats. Eggs are also a very good source of protein.

The data set establishes a hierarchy of foods based on their carbon cost. If you notice, the food ranking is very similar to the ideal diet using the food pyramid, which recommends eating more of the foods with the lowest impact. Eat more plant sourced food. Eat in moderation those that bled and walked on fours, or substitute them with anything that flies or swims.

In essence, what’s good for your gut is good for the planet. So the next time you bite into your food, think about how it’s going to impact your world, literally.

Get the full report, the Systematic of greenhouse gas emissions for different fresh food categories from the Journal of Cleaner Production.