For many people, Christmas Day is going to look extremely different this year. But individuals can still indulge in positive changes, particularly when they are contemplating what to eat and how to cook Christmas dinner.
Sustainable dietary advice has recommended that it is best to decrease the consumption of meat and increase the consumption of locally sourced and in-season plant-based proteins, vegetables and fruits that people eat. It is already known that people who make slight changes to their diet will not only benefit the environment but would also benefit their health.
But according to a new study from The University of Manchester, performed in association with Brunel University London, the Institute of Sustainable Food at the University of Sheffield, and City, University of London, food can also have a significant impact on the surroundings because of the greenhouse gas emissions (GHG) generated through numerous cooking methods. The study was recently published in the Nature Food journal on December 11th, 2020.
A lot of people are thinking carefully about what type of food to eat, or how it's packaged or transported but, in terms of climate change, it is sometimes more important to consider how the food is cooked.
Sarah Bridle, Professor, The University of Manchester
Professor Bridle continued, “Our research showed that up to 60 percent of the climate impact of foods can come from cooking—particularly for the most climate-friendly foods like vegetables, when baked in the oven. Whereas appliances like microwave ovens and pressure cookers are generally used for less time, and so use less energy and contribute much less to climate change.”
According to Dr. Christian Reynolds, a visiting researcher from the Institute of Sustainable Food and a Senior Lecturer at the Centre for Food Policy, City University, “Estimates of food-related GHG emissions usually only consider the supply chain up to the retail and purchase stages, but our research has found that consumption can contribute up to around 60 per cent of the overall emissions for the complete life-cycle of specific foods. So reducing these processes can reduce the damage they do to the environment.”
Considering that a traditional roast Christmas dinner is a cherished one for a majority of families worldwide, the new study has identified several methods in which the traditional Christmas dinner could be made slightly more sustainable to enjoy those favorite festive foods, without affecting the planet.
Reduce Meat Consumption
Although Christmas dinner does not stand canceled as such, the production and consumption of 1 kg of protein provided by meat products can lead to more emissions of greenhouse gas when compared to a passenger who flies from London to New York.
In other words, 1 kg of beef protein produced on a British hill farm can create the equivalent of 643 kg of carbon dioxide gas; however, 1 kg of lamb protein reared in the same location can produce even more at 749 kg, chiefly because of their extended oven-roasting cooking times.
However, investigators do not recommend throwing out the entire turkey because the good news for traditionalists is that turkey generates less GHG emissions when compared to other meat types, so it still presents a better option for Christmas dinner. Evidently, trying one of the several meat-free alternatives, which are presently available, has an even greater effect.
Reduce Food Waste
But the question is whether an entire turkey is actually needed. While this may not apply to a small family, one solution is to reduce the portion sizes, making sure that there are only minimal leftovers, and not become too ambitious with the number of dishes prepared. This is because food waste also has a significant effect on environmental damage.
One recommendation includes buying smaller turkey crowns or mini-roasts and dividing the portions of light and dark meat, because smaller roasts also cook faster, reducing the environmental effects of roasting meat in an oven.
Reduce the Time Spent on Cooking
It is not just a matter of food, but the way people cook it that impacts GHG emissions. In this respect, ovens are the worst culprits of the kitchen, largely because of the high energy demands and extended cooking times involved in roasting meat.
Decreasing the time taken for cooking can help decrease GHG emissions. If some foods are partly cooked in a microwave, it can also reduce the time needed to cook food in the oven without considerably affecting the texture or taste.
The study observed that the effects of cooking in a microwave, boiling and steaming are similar for defrosting, reheating and preparing fruits, vegetables, fish and eggs, while retaining more of the water-soluble minerals and vitamins.
Besides, there is another method through which people could halve the environmental effect of roasting a turkey on Christmas Day.
In 'Sous vide,' meaning 'under vacuum' in French, the roast is placed in a vacuumed plastic bag or pouch, and submerged in a heated water bath for a duration of eight hours until the internal temperature of the joint reaches 55 °C, in the case of white meat, to 75 °C in the case of dark meat. The roast is subsequently unwrapped and transferred to a hot skillet to sear its surface, preserving both the flavor and texture.
Our results underscore the importance of looking at the whole lifecycle of food when assessing the environmental impact of our supply chains, as consumption alone is such a significant contributor to the damage GHGs do to the environment.
Dr Christian Reynolds, Visiting Researcher, Institute of Sustainable Food
Dr. Reynolds continued, “But for those not brave enough to try ‘boiling’ their turkey the fancy French way, investing in an electric pressure or slow cooker, both incredibly energy-efficient ways to cook but still not widespread in the UK, can have a similar result and substantially reduce the environmental impact of more traditional cooking practices.”
“Just pop the roast in the slow cooker on its ‘low’ setting with some water and cook for eight hours. Best to start on Christmas Eve though so you don’t forget!” Dr. Reynolds concluded.
Frankowska, A., et al. (2020) Impacts of home cooking methods and appliances on the GHG emissions of food. Nature Food. doi.org/10.1038/s43016-020-00200-w.