sustainable diet

What does a sustainable diet look like? By Carolyn Auma

Diets need to change if we are to live more sustainably. But exactly what is a sustainable diet? Grantham Scholar Carol Auma led a Journal Club session to discuss sustainable diets.

Carolyn Auma
Grantham Scholar Carolyn Auma

Food chains and climate change

The food chain encompasses various processes. Everything from the farm to the consumer is part of that chain.

Globally, the food chain produces a substantial amount of anthropogenic gases (aka greenhouse gases). So in order to address the challenges of sustainability, we have to look at the whole chain. And it has been proposed that wide-spread consumption of a ‘healthy and environmentally sustainable’ diet is paramount.

Sustainable diets

Although there is no clear picture of what such a diet might look like on a plate, there is a general consensus of what such a diet includes. Lower consumption of meat and meat products. Limited consumption of dairy and dairy products. And the inclusion of more plant-based foods in the form of cereals, pulses, grains and fresh tubers.

The rationale is that meat and meat products have a high carbon footprint relative to other food groups. And this is coupled with the adverse health effects that are likely to arise from over consumption of meat and meat products, especially processed meats.

The challenges of eating a healthy sustainable diet

I chose The challenges of eating a healthy sustainable diet by Clonan and Holdsworth (my supervisor) for discussion in Journal Club. My hope was that it would encourage discussion of 3 main points. Firstly, the challenges of defining what sustainable eating is. Secondly, advocating for dietary change towards more sustainable patterns. And lastly, what we might do to address such challenges.

Pertinent to the article was the need for public health nutrition practitioners and policy specialists to look at food consumption as a process. A process that cannot be isolated from other processes like cooking, purchasing and growing. Basically, any attempt to address consumption has to take into account other processes associated with eating that could hinder or accelerate consumption.

Additionally, it is not enough to only look at the nutritional and ‘greenhouse gas impact’ aspects of sustainability. Other factors including the social, cultural economic and ethical dimensions need to be addressed too.

How do we measure sustainable diets?

One issue we discussed was the increased focus of sustainable diets in relation to greenhouse gas emissions (GHGEs). And to a lesser extent, water footprint and land use impact.

Sustainable diets are a relatively new concept. As such, there are not many well developed quantitative, or even qualitative, measures for sustainable diets aside. Currently GHGEs are usually used, and they are often calculated using the Life Cycle Analysis (LCA) method. LCA has its shortcomings. For example, the LCA is not adaptable to low-and middle-income countries because the impact factors were developed with the food production systems of high-income countries in mind. What happens then if we want to assess the sustainability of diets in low- and middle-income countries where a nutrition transition is reportedly happening at an accelerated rate?

And is it a given that a low GHGE food will also be one of low water footprint? For example, vegetables and fruits are reportedly more sustainable in terms of GHGEs. But some fruit and vegetables require huge amounts of water to be produced.

Cultural, social, ethical and economic aspects

We all agreed that sustainable in diets should encompass many things. Cultural, social, ethical and economic aspects must be considered. Is there a point in having a theoretically modelled diet that is respectful of biodiversity, has low GHEGs and land use impact, and is nutritionally adequate – but isn’t affordable for most of the population?

Another interesting topic we identified and discussed from the paper was how something as simple as packaging transforms a food product’s carbon footprint. This led us onto the feasibility of local and seasonal consumption.

Local and seasonal eating

Is eating local and seasonal feasible? For example, in the UK, it is difficult for the average consumer to decipher what is a seasonal. Because in the UK a wide array of foods are available all through the year. If we advocate seasonal eating, are we looking at only seasons within the geographical confines of a particular country?  Or are we saying that they can import foods from a country in which the food is in season?

Could the environmental impact of foods be reduced by allowing foods to only be imported from within a particular geographical region? For example, imports to the UK come only from Europe. If we do this, are we being ethical or considerate of the farmer in Mexico who grows soya for an international market? And there are countries (e.g. like Singapore) that do not grow food. Can they be expected to eat local and seasonal?

Eat pragmatically

In the end, there was a general consensus among us for a sustainable diet that incorporates small amounts of meat, instead of advocating for everyone to go vegetarian. Also, it is easier to go vegetarian or reduce meat consumption when you have support. E.g. if you have friends and family that follow the same or similar dietary patterns.

Could it be possible to start with one meat-free day in a week and then advance it to more days until finally one is vegetarian?

Also, comparisons of sustainability are done in terms of large quantities i.e. production of one kilogram of beef results in X amount of GHGEs (in kilograms of CO2 equivalents). This is not relatable to the average consumer, so in advocating for sustainable diets, it may make more sense to break down the sustainability indicators into something that is relatable. For example, portion size, or serving size, or cup of tea etc.

Psychological and sociological factors

We also discussed the adage that ‘real men eat beef’. It may be a challenge to get ‘masculine’ men to embrace pulses and grains as their source of protein. This coupled with the fact that people have different personalities. People with an all-or-nothing mentality may decide to become vegetarian without any issues, but not everyone is like that.

There are also issues about the psychology of eating and people’s relationships with food which are largely ignored in sustainable diets. For example, many advocate ‘nose-to-tail consumption’ of meat. But there are stigmas around offal and ‘odd bits’ of animals. It was interesting that one of the group mentioned that her parents grew up in the UK eating offal. But because she did not grow up on that kind of diet, she finds it disgusting. In this sense there may be a generational divide with older people more open to sustainable animal consumption. Perhaps this could be addressed by ‘packaging’ those bits attractively in ways that can appeal to young people.

Change is complicated

Following our discussion of the content, it is clear that consumer-side interventions towards more sustainable consumption are not simple. It will need more than just telling people what and how to eat. The fact is that eating, whether healthy and sustainably or not, is a socially constructed process. It requires the unearthing of the economic, cultural, social, psychological and ethical contexts around it in order to be understood.

One important thing I have noticed, is the focus on adult populations with no discussion of children’s diets. I wonder if this is wise given that dietary habits are largely developed in childhood and can be difficult to change.

Are we going to allow children to eat as they do and then, at some later date, ask them to change? It may be easier to start now.


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