What does a sustainable diet look like? Journal Club with Carolyn Auma

It’s widely recognised that diets need to change if we are to live more sustainably. But the shape that a sustainable diet would take isn’t necessarily clear, especially when sustainability is competing with other factors like health. Grantham Scholar Carolyn Auma led a Journal Club session to discuss some of these issues, and in this blog post she sets out some of the debates.

This week’s paper

The challenges of eating a healthy sustainable diet‘ by A. Clonan and M. Holdsworth

Carolyn Auma
Carolyn Auma

When one hears about climate change and environmental sustainability, it may not naturally conjure an image of a treat as simple, harmless and delicious as pigs-in-blankets, as seriously having anything to do with it. And yet recent research suggests otherwise.

The food chain encompasses various processes, all the way from food production at the farm to consumption by the final consumer (for example, in the household). It has been reported that in the UK, and indeed globally, the food chain produces a substantial amount of anthropogenic gases (greenhouse gases) which have been responsible in part for driving global climate change. In order to address the challenges of environmental sustainability, therefore, it is not enough for us to look at interventions aimed at the food production side alone, as this is only part of the food chain. In trying to address the ramifications that consumption has on environmental sustainability, it has been proposed that encouraging the adoption and wide-spread consumption of a ‘healthy and environmentally sustainable’ diet is paramount.

Although there is no clear picture of what such a diet might look like on a plate – an image which the average consumer might find easier to relate to – there is a general consensus that such a diet includes, among other features, lower consumption of meat and meat products, limited consumption of dairy and dairy products, and inclusion of more plant-based foods in the form of cereals, pulses, grains and fresh tubers. The rationale behind advocating for a diet that is particularly low in meat and meat products is their high carbon footprint, relative to other food groups, coupled with the adverse health effects that are likely to arise from over consumption of meat and meat products, including processed meats.

The paper we discussed in Journal Club was an editorial piece, but I was hoping that it would spur us in the direction of discussing the possible challenges around defining what sustainable eating is; advocating for dietary change towards more sustainable patterns; and what we might possibly 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 which cannot be isolated from other processes like cooking, purchasing and growing (Clonan and Holdworth, 2012). In essence, any attempts to address consumption, will have to take into account how other processes associated with the act of eating could hinder or accelerate consumption. Additionally, in looking at the sustainability of diets, it is not enough to only look at the nutritional and ‘greenhouse gas impact’ aspects of sustainability. Other factors including the social, cultural (Clonan and Holdworth, 2012) economic and ethical dimensions need to be addressed in equal measure.

Some of the issues we discussed were the increased focus of sustainable diets in relation to greenhouse gas emissions (GHGEs, carbon footprint) and, to a lesser extent, water footprint and land use impact. This could possibly be because sustainable diets are a relatively new concept and as such there are not many developed quantitative, or in fact qualitative measures, for sustainable diets aside from GHGEs, usually calculated using the LCA method, which in itself has its own 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?) We all agreed that sustainability in diets should encompass many things, with cultural, social, ethical and economic (financial) aspects being major parts to be considered. Is there a point in having a theoretically modelled diet that is respectful of biodiversity, has low GHEGs and land use impact, is nutritionally adequate and yet is neither affordable for most of the population or produced in the most unethical way?

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 to discussing how feasible local and seasonal consumption is. If we are looking at sustainable diets mostly in terms of GHGEs, is it necessarily a given that a low GHGE food will also be one of low water footprint? For example in the case of vegetables and fruits, which are reportedly more sustainable in terms of GHGEs, is their sustainability not offset by the fact that some of the very same vegetables require huge amounts of water to be produced? And is eating local and seasonal feasible? For example, in the UK, it is even harder for the average consumer to decipher what is a seasonal food since now a wide array of foods are available all through the year and across all seasons. If we truly advocate for 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 that they cannot grow during particular seasons from a country in which the food is in season? Could the environmental impact of foods also be reduced by advocating for 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 is growing soya bean, knowing that it will be exported to Europe and America to sustain the animal industry? How about countries like Singapore that do not grow food? Can they be expected to eat local and seasonal?

On the whole, in our discussion there was a general consensus in favour of a sustainable diet that incorporates small, realistic amounts of meat instead of advocating for everyone to go vegetarian, which might not work. Also, it is easier to go vegetarian or reduce meat consumption when you have support (eg, 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 ie, 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 – a portion size, or serving size, or cup of tea etc.

We also discussed the common adage that ‘real men eat beef’ and how this might be a challenge in getting ‘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 or personality could 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. In the consumption of animal products and the noise-to-tail consumption advocated for in the sustainable eating principles, there appears to be a stigma around eating offals and ‘odd bits’ of animals like feet and sweetbreads. It was interesting that one of the group mentioned that her parents grew up in the UK eating those very parts of the animal, and as such, right now, they are open to the idea of eating them. But because she did not grow up on that kind of diet, she finds it disgusting and repellent. So when we are advocating for more wholesome consumption of the animals, are we being mindful of how we are going to get this message across the generational divide? Older people seem to be more open to sustainable animal consumption, in this sense, than younger people who have grown up eating gourmet beef. Perhaps this could be addressed by ‘packaging’ those bits attractively in ways that can appeal to young people.

Following my reading of this paper, and our discussion of the content, it is clear that consumer-side interventions towards more sustainable consumption are not simple and will require 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 which 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, which I believe is important in advocating for more sustainable diets, is the larger focus on adult populations relative to children’s consumption. I am left pondering whether this is a wise move given that dietary habits are largely developed in childhood and can be difficult to change? Are we then going to allow children to consume the diets that they are currently consuming and then, at some later date, ask them to change towards healthier and more sustainable eating patterns?


Clonan, A. and Holdworth, M. (2012). The Challenges of Eating A Healthy Sustainable Diet. The American Journal of Clinical Nutrition, 96, 459-60