Revealed: how to reduce the environmental impact of your Christmas roast

The Christmas roast – a centerpiece of the Christmas celebration for many families across the globe – has a high environmental impact, but a new study by University of Sheffield has revealed how the traditional meal can be made more sustainably.

xmasdinnerDr Christian Reynolds, Knowledge Exchange Research Fellow (N8 AgriFood project) in the University of Sheffield's Department of Geography, analysed the energy used in preparing a roast beef and Yorkshire pudding seven different ways – through adapting the cooking method, ingredients and the efficiency of the appliances used.

He found that by combining sustainably sourced meat, reducing the portion size and using modern cooking methods, the environmental impacts of the classic meal can be reduced by more than half.

The Christmas roast - like most meals using animal products - has a high environmental impact and the joint of meat itself can account for up to 60 and 70 per cent of the environmental impacts of the entire meal because of the large amounts of water, land, and feed required produce it. Shifting to a more sustainable type of meat (such as Turkey or Ham, rather then Beef or Lamb), or going for a plant based option, is a great first step. Purchasing sustainable and ethically farmed meat can also result in small environmental savings. The next step is to reduce the amount of meat consumed.

Dr Reynolds suggests a portion size of around 125g per person, meaning 50-70g for Christmas lunch and a manageable amount for leftovers the Boxing day.

Cooking is the other contributor to Christmas roasts’ high environmental impact. The oven is an inefficient way of cooking meat at hot temperatures, and for long periods of time. The environmental impact of roasting a joint of meat or a whole bird for over an hour in an oven contributes 20 to 30 per cent of the environmental impacts of the entire meal. In addition to this, people in the UK tend to overcook their meat by 41 minutes, which contributes to the environmental impacts through pointless energy use.

Dr Reynolds says a benefit of cutting meat portions for a sustainable roast is that it will have a shorter cooking time, meaning it will use less energy to cook.

Cooking sous vide involves placing a joint of beef in a vacuumed plastic pouch or bag, and submerging this in a heated water bath for several hours until the internal temperature of the joint is between 55-60C. The joint is then unwrapped and placed in a hot skillet to sear its surface.

This gives the cook total control of the texture and flavour and can use less than half the energy of a traditional oven method.

However, Dr Reynolds said: “Unfortunately, reducing the environmental impact of our Christmas roast will not hugely reduce the overall environmental impact of our diet. For this we need to further reduce our meat consumption and increase our consumption of plant based proteins, fruits and vegetables across all meals.

“In comparison to other more plant-forward meals that could be eaten, a sustainable Christmas roast has high environmental impacts. For this reason, even the sustainable Christmas roast should be kept as a special meal, and not eaten every week.

“The good news is that, if even an environmentally damaging meal such as the Christmas roast can be made a little more sustainable, it should be possible to create appetising yet sustainable versions of other popular dishes too.”

The research was published in the journal Energy Procedia.

Read Dr Reynold's piece 'How to cook a more sustainable Sunday roast' on The Conversation.

Dr Reynolds is also hosted an event at this year’s Economic and Social Research Council Festival of Social Science which explored what matters to us about the food we eat – whether it’s healthy, if we care about where it comes from and if it sustainable.