The study, carried out by a research group across six universities, surveyed 765 participants cooking thirty of the most commonly consumed food items in the UK.
Over 50% of total Greenhouse Gas contributions for vegetables such as potatoes, carrots, cauliflower and cabbage were found in the cooking, rather than the production stage. Cooking meats such as beef and lamb accounted for only 8% of their total CO2 contributions, although they had a far higher absolute CO2 figure, due to higher environmental impact during production.
These findings demonstrate that cooking instructions which manufacturers place on food packaging can play a vital role in lowering CO2 emissions. In their latest consumer tracker, the Food Standards Agency found 66% of UK households cook food from scratch every week. Nudging consumers towards less energy intensive cooking methods could have a significant effect on reducing CO2 emissions in the food sector.
Findings from the report noted that oven cooking has the highest impact, while slow cooking, sous vide or microwave cooking contributed the lowest. Roasted beef contributed 6.97kg of CO2 per kg of cooked meat, while roast potatoes contributed 2.27kgCO2 per kg of cooked food. Microwaved potatoes contributed only 0.33kgCO2 per kg of cooked food
The report does acknowledge that flavour profiles differ between methods and this is a significant factor in consumer choice.