Examples of interventions include replacing some of the confectionery items on offer with fruit or nuts, sugary drinks with no or low sugar options, alcoholic with non-alcoholic drinks and meat based with plant-based meals.
Theresa Marteau at the University of Cambridge and colleagues explain that suboptimal diets - particularly the consumption of energy dense foods, meat, and alcohol - are one of the largest contributors to premature death and preventable diseases worldwide, contributing also to health inequalities and environmental harm.
So they set out to summarise the evidence supporting availability interventions in a form useful to policy makers. They searched the scientific literature to update a Cochrane review published in 2019 and identified nine real world studies (including four new studies) showing consistent and often substantial effects of availability interventions on consumer selection of healthier or more sustainable options, with no evidence of adverse effects, including increasing health inequalities.
For example, increasing the proportion of vegetarian meal options in a cafeteria from 25% to 50% decreased the selection of meat meals by almost eight percentage points (from 81% to 73%). Similarly, increasing the proportion of lower energy food options available in cafeterias from 42% to 50% reduced the calories purchased per transaction by almost five percent compared with baseline (from 384 to 366 kcal).
And early results from a study of online supermarket purchases suggest that decreasing the proportion of alcoholic drinks available from 75% to 50% and 25% increasing the proportion of non-alcoholic beers and wines and soft drinks selected from 24% to 32% and 45% respectively.
The authors acknowledge some uncertainties, such as whether these findings can be applied to low and middle income countries, and the impact of population preferences (social norms) on what we eat.
And they point to challenges that they say may contribute to the relative neglect of these interventions, such as not fitting with the dominant public discourse around personal responsibility for unhealthy behaviour, and resistance by businesses fearing loss of sales.
Nevertheless, they say their findings “should help highlight the opportunities for including [availability interventions] in strategies promoting health and sustainability.”
They conclude: “Evidence for the effectiveness of availability interventions is now mature enough to merit serious consideration by policy makers and others as an effective addition to interventions in public and private sector settings aiming to shift currently unhealthy and unsustainable patterns of consumption towards unmet population health and net zero goals.”