The Paper of the Month for March is ‘Ready meals, especially those that are animal-based and cooked in an oven, have lower nutritional quality and higher greenhouse gas emissions and are more expensive than equivalent home-cooked meals’. The blog is written by authors Magaly Aceves-Martins, Philippa Denton and Baukje de Roos and published in Public Health Nutrition, and is free to access for one month.

Ready meals are a popular choice in the UK, and it is estimated that almost 90% of us eat them. Many ready meals can be classified as ultra-processed foods, which often have multiple added ingredients such as sugar, salt, fat, artificial colours, or preservatives, and consumption of ready meals has been associated with an increased risk of obesity. However, the jury is still out on the nutritional quality of ready meals. In our study, the average level of free sugars in 54 chilled or frozen ready meals was significantly higher than in equivalent home-cooked meals, but we found no differences in their salt or fat content.

Currently, there is uncertainty regarding the environmental impact of ready meals. In the UK, it is estimated that the ready meals contribute almost 16% to total greenhouse gas (GHG) emissions from the food and drink sector. We compared GHG emissions in a large range of ready meals and equivalent home-cooked meals, enabling us to compare animal versus plant-based meals, and assess the effects of various cooking methods. As expected, GHG emissions – from farm to supermarket shelf – of animal-based meals were twice as high as plant-based meals, both in ready meals and in equivalent home-cooked meals. Ready meals, especially those that were animal-based, had significantly higher GHG emissions than equivalent home-cooked meals. Plant-based ready meals and equivalent home-cooked meals had comparable GHG emissions. Cooking of all meals added further emissions – oven cooking added up to 20% to GHG emissions. In contrast, stove and microwave cooking were the better environmental choices, adding only up to 4% and less than 1% to GHG emissions respectively. Overall, the most environmentally friendly and cheapest meals were plant-based and home-cooked on a gas or electric stove, or in the microwave.

Many of us would advocate home cooking over eating ready meals for health, socio-cultural, economic, or indeed environmental reasons. But ready meals have become an integral part of our food culture. These meals can be ultra-processed, high in salt and fat, and low in fibre, but they don’t have to be. Recipes for ready meals vary considerably; thus there is significant scope for the food industry to improve the nutritional quality and carbon footprint of a wider range of products. From a consumer perspective, reducing food waste while consuming fewer calories, and choosing products with smaller environmental impacts, such as plant-based meals, are arguably the most effective ways to reduce GHG emissions. Producers could optimise their ingredient choices, methods of manufacturing and refrigeration, and minimise waste throughout the life cycle of ready meals, which are all major determinants of GHG emissions. As academics, we need to improve how we source and apply ‘Life Cycle Assessment’ datasets to provide us with more granular and accurate GHG emission data, for a more comprehensive selection of food products, to fully appreciate the opportunities for more healthy and environmentally friendly ready meals.

Each month a paper is selected by one of the Editors of the six Nutrition Society Publications (British Journal of Nutrition, Public Health Nutrition, Nutrition Research Reviews, Proceedings of the Nutrition Society, Journal of Nutritional Science and Gut Microbiome). Take a look at the entire Nutrition Society Paper of the Month Collection.