Affordable, healthy, and sustainable diets across all income groups in the UK

Sustainable diets

The Nutrition Society Paper of the Month for April is from Public Health Nutrition and is entitled Healthy and sustainable diets that meet greenhouse gas emission reduction targets and are affordable for different income groups in the UK’ by Authors Christian J Reynolds, Graham W Horgan, Stephen Whybrow and Jennie I Macdiarmid.

It is well known that dietary intakes are contributing to the high prevalence of noncommunicable diseases, environmental degradation, as well as accelerating climate change. While we have a good understanding of the principles of healthy and sustainable diets, the challenge is to alter dietary habits. Dietary habits, however, are difficult to break, so proposing changes where people need to deviate as little as possible from their own diets may facilitate a shift to healthy and sustainable diets. Further, this can only be achieved if these dietary changes are also affordable for all income groups.

This study investigated whether healthy and sustainable diets could be created while minimising the deviation from current dietary intakes in different income groups, without increasing cost. Diets needed to meet nutrient requirements and food recommendations (i.e. reduce red meat, increase fish, fruit and vegetables) as well as reduce greenhouse gas (GHG) emissions. Household food purchase data from the UK Living Cost and Food Survey (2013) were used to determine current diets and amount spent on food and drinks across five income groups.

The highest income group had the greatest GHG emissions associated both with their current diet and when nutritional requirements were imposed. To avoid spending more on food all income groups had to make bigger dietary changes than when there was no budget constraint, but this was more so for low incomes than those in high income groups. By introducing a maximum level for GHG emissions all income groups needed to make even more but similar amount of dietary change to reach healthy and sustainable diets, albeit at a slightly lower cost. As expected, the type of dietary changes were broadly the same across all income groups; reduce consumption of animal-based products and high fat/high sugar foods and increase plant-based foods. However, the type of foods in these broad categories differed between income group, e.g. different types of meat. The study illustrated the trade-off between cost, achieving healthier diets with low GHG emissions, and the amount of deviation from current dietary habits.

Experience shows that changing dietary habits is difficult, not least because it can have personal, social and economic consequences. Some people perceive the shift to healthy and sustainable diets as too big and too difficult. This study has shown that these diets can be created while minimising change from current eating patterns, using a variety of combinations of different foods, and keeping them affordable. Thereby, they can be tailored to the needs of different income groups, which may make dietary change more achievable.