Key Studies Diet

Does altering the availability or proximity of food, alcohol and tobacco products change their selection and consumption?

Changing our food environments, by making certain foods less available or less convenient to access, may be one way of reducing how much we select, purchase or eat. Until now, the possible impact of such changes has not been known.

We conducted a Cochrane Review to assess whether altering the availability (the range of options) or proximity (the distance at which they are positioned) of food products changes how much they are selected (such as purchased) or consumed. We searched for all available evidence from randomised controlled trials, and found 24 studies, including more than 3000 participants, all on food.

This review provides the most conclusive evidence to date that people select less of a type or range of food when there are fewer different options of that food available to choose from. For example, people select fewer unhealthy products from vending machines or in cafeterias when there are fewer unhealthy options available. The results are less clear on how this affects the amount of food that is actually consumed. This review also provides the most conclusive evidence to date that people consistently consume less of a food when it is placed further away than when it is nearer to them, although effects on selection are very unclear.

To read the findings of the study in full, click here.

Hollands, G.J., Carter, P., Anwer, S., King, S.E., Jebb, S.A., Ogilvie, D., Shemilt, I., Higgins, J.P.T., Marteau, T.M. (2019). Altering the availability or proximity of food, alcohol and tobacco products to change their selection and consumption. Cochrane Database of Systematic Reviews; 8:CD012573.

Does increasing the proportion of healthier options in cafeterias lead to healthier purchasing?

Six English worksite cafeterias increased the proportions of healthier cooked meals, snacks, cold drinks and/or sandwiches available. Healthier options were defined as those with fewer calories (kcal). When cafeterias offered these healthier options, there was a 7% reduction in calories purchased from targeted food categories. Increasing the proportion of lower calorie foods in worksite cafeterias seems a promising intervention for healthier consumption.

Impact of increasing the proportion of healthier foods available on energy purchased in worksite cafeterias: A stepped wedge randomized controlled pilot trial. Pechey, R., Cartwright, E., Pilling, M., Hollands, G. J., Vasiljevic, M., Jebb, S. A., & Marteau, T. M. Appetite.

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Taxing sweet snacks may bring even greater health benefits than taxing sugar-sweetened drinks

The UK Government levy on sugary drinks producers started in April 2018. This will potentially influence the cost of a large range of non-alcoholic beverages. Our new study (published 26th April 2018) looks at how increasing the price of snack foods might compare in impact. We found that a 10% increase in the price of sweet snacks could lead to a similar reduction in consumer demand as the same price increase for sugar-sweetened drinks. However, such a price increase is estimated to have knock-on effects that may further reduce purchases of sugar-sweetened drinks and other snacks. Furthermore, as sweet snacks provide twice as much sugar in the diet as sugar-sweetened drinks, the overall reduction on sugar intake could be even greater than that observed with price increases for sugar-sweetened drinks.

Are sweet snacks more sensitive to price increases than sugar-sweetened beverages: analysis of British food purchase data. (2018). Smith RD, Cornelsen L, Quirmbach D, Jebb SA, Marteau TM. BMJ open.

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