Life cycle environmental impacts of convenience food: Comparison of ready and home-made meals

Abstract

This paper compares the life cycle environmental impacts of ready-made meals manufactured industrially with meals prepared at home from scratch. A typical roast dinner consisting of chicken meat, vegetables and tomato sauce is considered. The results suggest that the impacts of the home-made meal are lower than for the equivalent ready-made meal. For example, the global warming and human toxicity potentials are up to 35% lower and eutrophication, photochemical smog and ozone layer depletion are up to 3 times lower. The main reasons for this are the avoidance of meal manufacturing, reduced refrigeration and a lower amount of waste in the life cycle of the home-made meal. For the ready-made meal, the lowest impacts are found for the frozen meal prepared from fresh ingredients and heated at home in a microwave. The worst option for most impacts is the frozen ready-made meal with frozen ingredients that is heated in an electric oven. For the same cooking method, chilled ready-made meals have higher impacts than the frozen. The type of refrigerant used in the supply chain influences the impacts, particularly global warming and ozone layer depletion. The contribution of packaging is important for some impacts, including global warming, fossil fuel depletion and human toxicity. The main hotspots for both types of meal are the ingredients, waste and cooking method chosen by the consumer. Using organic instead of conventional ingredients leads to higher impacts. Sourcing chicken and tomatoes from Brazil and Spain, respectively, reduces environmental impacts of the meals compared to sourcing them from the UK, despite the long-distance transport. The findings of the study are used to make recommendations to producers, retailers and consumers on reducing the environmental impacts from food production and consumption.