Can people afford to switch to sustainable diets?

2019 Alpro Foundation Award for best scientific publication

One of the commonly reported barriers to adopting a sustainable diet is the perceived higher cost. However, Dr Reynolds and team from the Rowett Institute at Aberdeen University have demonstrated in their research that it is possible for all income groups to consume a healthier and more sustainable diet.

Study overview

Dr Reynolds’ research investigated the cost implications of shifting towards more sustainable eating habits for different socioeconomic groups in the UK. He highlights the trade-offs needed between health, cost, and sustainability and encourages thinking more broadly about interplays between nutrition, public health policy, and the wider food system.

Using linear programming methods, the researchers modelled reduced Greenhouse Gas Emission (GHGe) diets that met UK dietary recommendations. Alternative diets were modelled across five income quintiles, whilst minimizing the changes from baseline diets and without increasing the cost from current food budgets (Data from 5,144 UK households in “The 2013 Family Food Module of the Living Costs and Food Survey” were used as baseline).

As a result, affordable, healthy and sustainable diets were proposed which are realistic for different sections of the population. The study confirms that plant-based diets which reduce, without necessarily eliminating animal-based foods, are optimal for human and planetary health.

Key findings

• A 57% reduction in diet-related GHGe, as per the UK 2032 target, was possible across all income groups without eliminating any food group currently consumed

• An 80% reduction in GHGe, as per the UK 2050 target, was not possible whilst meeting nutritional constraints

• All modelled diets included a decrease in meat, dairy, eggs and high-fat/high-sugar foods, alongside an increase in fruit, vegetables, starches and seafood were increased

• The proposed sustainable diets reduced cost of the diet across all income groups by 18-47p per day

• However, there were several differences in the modelled diets between low and high-income groups:

• A greater difference from current eating patterns was required amongst low-income groups

• Specific dietary changes were required to meet nutritional and sustainability targets for each group. For example, high-income groups needed to reduce alcohol consumption whereas low-income groups needed to reduce milk and high-fat/high-sugar foods

• Differences were observed within food groups such as type of starches or meat products, in line with differences in the baseline diet

Conclusion

The study highlights the importance of ensuring that dietary policies are realistic and achievable across all income groups. Tailored interventions that promote sustainable diets which minimize the change from current diets may be more acceptable and effective than general population-wide advice.

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