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What is sustainable food? - Part 3

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This is the third article in our sustainable food series. In part one, we discussed what influences the climate impact of our food, and in part two, we looked at the different types of water that goes into producing food and how to increase the biodiversity within food production systems.

In this final part of the series, we discuss the balancing act between different systems such as low input systems, high welfare systems and environmental benefits.

What is sustainable food? - Part 3

Looking through one lens

It can be very easy when thinking about sustainable food to focus on a particular aspect, whether that is climate impact, water or biodiversity. However, food production is part of a complex biological process and therefore actions in one area can lead to consequences in others. For example, if you look at sustainability through a climate impact lens you would drive food production down the intensive production route. The lowest climate impact crop production systems tend to be the intensively managed arable systems that optimise fertiliser use and maintain high levels of disease, pest and weed control through the use of pesticides. This is because these systems are able to produce high levels of reliable yield.

The same is also true for livestock systems. Intensively produced (usually housed) livestock that are fed concentrated feed to encourage rapid growth and higher yields tend to have lower emissions than extensive grass fed or free range systems. The main driver behind this is the fact that the quicker an animal gets to slaughter weight, or the more milk/eggs it produces per year, the less emissions of manure (and methane for ruminants) it produces per unit of production. However, these intensive production systems are often perceived by the consumer to have lower welfare status than grass fed or free range production systems. 

It is therefore important, when looking at the overall sustainability of a food production system, to look at multiple aspects of sustainability in a more holistic way as different types of production systems can deliver different social and environmental benefits. 

Low input


Conventional crop production is often associated with high utilisation of pesticides and artificial fertilisers. These chemicals are applied to the crop to ensure that optimal yields are achieved on the available land without losses due to pests, disease, or weed competition, and without limitation of nutrients. Some chemicals can also reduce the risk of food contaminants such as mycotoxins and pests. However, pesticides and fertilisers are associated with negative impacts on biodiversity, water quality and, in some cases, human health. Therefore, it is important that the usage of these chemicals is managed to minimise the negative impacts on the environment and health, whilst optimising crop production and quality.

Reducing or eliminating artificial chemicals from production systems may seem to be a good idea environmentally, but in the absence of these chemicals, yields may decline and there would be a greater risk of crop failure in years of high pest or disease pressure. In order to counter yield reduction, it would be necessary to cultivate greater areas of land. Therefore, if we are to meet the food requirements of an increasing human population, artificial chemicals have a role to play in supporting efficient crop production. Use of nitrogen fertilisers is widespread in the crop sector to enhance yield, although in mixed farming situations it is possible to utilise organic manures as a partial replacement for artificial fertilisers.


In terms of livestock, there are extensive low input production systems such as grass-fed cattle and sheep. These systems rely mostly on grazing pasture (either naturally occurring, or improved, to provide most of the livestock’s nutritional requirements). Over winter, when stock are housed to protect the grassland from damage and to provide them with shelter, they are fed conserved forage such as grass silage. These extensive grass-fed systems usually mean that the animals take longer to reach maturity and therefore consume more feed and water, produce more manure, and emit more methane than intensively produce animals. However, they are fed on a diet that requires fewer inputs than some of the more intensively fed stock, can aid in the maintenance of biodiverse grasslands and can be produced in locations (such as the UK uplands) where other forms of food production are almost impossible.

Products bearing the LEAF marque are from farms which are certified users of a whole farm approach to sustainable food and farming. These products are committed to low input, energy efficiency, water management and nature conservation.

High welfare

The UK’s animal health and welfare standards are among the highest in the world. On top of this, many UK farmers also choose to enrol in Assurance Schemes which require them to enhance their systems and improve welfare beyond the basic legal level, ensuring that high quality, welfare-friendly products are available on the UK market.

Housing livestock

Intensive production practices such as housing and use of high levels of concentrated feeds such as cereals and oilseed meals is commonly used to reduce growth times or increase yields. This is beneficial because it reduces methane and manure production per unit of product produced (kg meat, dozen eggs, litre milk), and therefore climate change emissions. These systems are usually intensively monitored with careful attention paid to ventilation and temperature to minimise the risk of disease and illness within the livestock group. However, there is also the perception amongst consumers that housing of animals and taking away their access to pasture is a loss of one of their freedoms and is therefore not as good for welfare as grazing or free-range systems. Housing of stock can potentially open up areas of grassland to alternative management practices that may enhance biodiversity and reduce loss of pollutants to water, however this land may alternatively be repurposed to crop production instead, resulting in cultivation of grasslands, loss of biodiversity and emission of stored carbon from the soil. 

It should be noted that many grass-fed systems will also house stock for periods of time over winter to protect the land from poaching, provide comfortable stable footing for stock, and also shelter them from the elements. 


In this series, we’ve examined some of the different aspects of sustainable food. If you want to select sustainable food, you should consider the production processes behind it and evaluate its sustainability; although your choice need not be all or nothing.

Different foods, and even the same foods produced in different regions, can have different levels of sustainability. Foods sourced from locations that don’t rely on deforestation, either directly or indirectly, limit the impact on the climate. Likewise, foods from areas or species which require little or no irrigation are more sustainable. Sourcing local, UK, foods ensures high standards of animal welfare, and you can gain a greater understanding of the production systems used to produce those stock. Additionally, selecting products which are certified based on their environmental credentials can be an easy way to increase the sustainability of your food choices.

However, it does not matter how sustainably produced your food is if you do not eat all of what you buy, as the emissions and water used to produced that food is wasted as soon as it goes in the bin. Therefore, the final step in selection of sustainable food is to only buy the food you need and ensure that you consume all that you buy. 

There are many sustainable food options available which do not require you to commit to a restrictive diet. Every food choice you make can make a big impact over time; so it is worth considering the points featured here next time you’re choosing what to buy.

About the Sustainable Food and Farming team

The ADAS Sustainable Food and Farming team help clients to address their sustainability challenges.

Our agricultural background means we’re equally at home meeting face-to-face with farmers as we are engaging with senior management in global food and drink businesses.

This gives us the unique ability to work across all stages of the supply chain. For more information on improving sustainability within your supply chain, please contact

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