What is a sustainable diet? A diet that is healthy, affordable, environmentally sustainable and culturally acceptable. That is a tall order. It is easy to think of diets that are affordable but unhealthy, or diets that are healthy but environmentally unsustainable, or diets that are environmentally sustainable but culturally unacceptable. But all together? Its important that we try to do this - we have to operate more consciously in a resource constrained world.
The exam topic I was set by the organisers was to say something useful on metrics. My powerpoints are here.
We had an interesting presentation by Jennie Macdiarmid from Rowett Research Institute at Aberdeen University on the well project in partnership with the World Wildlife Fund - on what an affordable Scottish diet looks like - one that meets dietary minimum requirements, is culturally acceptable (i.e. looks like actual Scottish diets) and, crucially, meets greenhouse gas emission targets.
It turns out that what is healthy is not the same as what is environmentally sustainable. In other words it is not all about reducing meat consumption. The results were generated by a relatively straightforward linear programming model. The innovation is incorporating emission data and limits into the model.
My presentation was about how it was essential to get some metrics on sustainable diets. This would force us to be specific, to make choices about what is in and what is out, to identify and assess tradeoffs and importantly, to tell us what difference it would make to policy choices and decisions.
I outlined a few related pieces of work that might be borrowed from: the Multidimensional Poverty Index, the Sarkozy Commission report, the Global Hunger Index, and the Hunger and Nutrition Commitment Index (HANCI) that IDS will release in January. Ultimately we want to know if equally healthy and affordable diets have different environmental footprints.
There are a number of technical challenges:
- Getting data on food consumption, on the nutrient composition of local foods, and on the environmental and resource use implications of the use of different foods in the diet. (We need a Global Database on Food Consumption at FAO, similar to the Global Database on Child Growth and Malnutrition at WHO - Graziano da Silva please note!).
- Getting data on government and private sector commitment to sustainable diets (important because this is an inherently "whole of government" affair).
- How to combine the data? Perhaps (1) via a nonlinear programme (or some variant) that generates diets that can serve as a starting point for discussions in the kitchen and in government meeting rooms, (2) in an index or (3) in terms of "agricultural growth that reduces hunger by x for z levels of input use"?
The technical tradeoffs are important but the preference or social welfare tradeoffs that consumers and policymakers are prepared to make are equally important.
They reflect values, tradition, history, politics and culture. To get at these tradeoffs we could use behavioural economics to test preferences through constructed situations, choices, and experiments - with different groups of consumers and different groups of policymakers to get a range of "who's values count?"
On the policy research side, the options seem to be:
- Find positive examples of sustainable diets and try to work out whether they have anything in common and whether policy played any role - deliberately or inadvertently
- Identify relationships that may serve as entry points for policy: e.g. prices, information, social norms, women's power in decision making
- Evaluate existing interventions that aim to promote sustainable diets (there aren't many to evaluate)
- Evaluate existing interventions that inadvertently have a positive or negative impacts on sustainable diets (e.g. the US farm subsidies to corn syrup production, the Common Agricultural Policy)
I found the workshop interesting - I learned a lot and met people outside of my usual circles.
I also got to see the first Daniel Carraso Foundation Award get presented to Jessica Fanzo, a worthy recipient. She has managed to combine bench work in molecular nutrition with community nutrition and policy research. She has worked with environmentalists, engineers, economists, agriculturalists, and even political scientists (e.g. Andres Mejia Acosta at IDS). Well done Jess.