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.

What is the potential impact of reducing portion sizes in worksite cafeterias?

Reducing the portion sizes of foods available in restaurants and cafeterias is one promising approach to reducing energy intake, but there is little evidence of its impact from randomised studies in field settings. In this paper, we provide the results of a pilot trial estimating the potential impact of reducing portion sizes of targeted foods in worksite cafeterias. Feedback after the intervention suggested it was broadly acceptable to customers and cafeteria staff. Each of the six cafeterias showed a reduction in daily energy purchased from intervention categories, but the overall reduction across all sites of 8.9% was not statistically significant. The results of this trial suggest that reducing portion sizes could be effective in reducing energy purchased from targeted food categories, but also that future studies will need to address factors that prevented optimal implementation, including site dropout and only reducing portion sizes of a limited range of products.

Impact of reducing portion sizes in worksite cafeterias: a stepped wedge randomised controlled pilot trial. Hollands GJ, Cartwright E, Pilling M, Pechey R, Vasiljevic M, Jebb SA, Marteau TM, 2018

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The TIPPME intervention typology for changing environments to change behaviour

In a new paper, published in Nature Human Behaviour, we introduce a new framework we have developed: the Typology of Interventions in Proximal Physical Micro-Environments (TIPPME). This provides a way to classify and describe an important class of interventions to change selection, purchase and consumption of food, alcohol and tobacco.

Presenting images of negative health outcomes leads to healthier food choices

Presenting images of negative health outcomes leads to healthier food choices

In an experimental study published in Health Psychology, we examine the impact on people’s choices of presenting food images paired with positive or negative images of the health consequences of eating those foods. We found that presenting images of negative health outcomes led to more healthy food choices, irrespective of whether they were paired with images of energy-dense snack foods or of fruit. Images of positive health outcomes did not alter food choices.

These results are consonant with a large and diverse body of research in psychology and public health showing that negative stimuli tend to have more impact on cognition and behaviour than positive stimuli. This work provides insights relevant to health communication interventions where aversive visual images are used to alter the consumption of products that impact on human health.

Pairing images of unhealthy and healthy foods with images of negative and positive health consequences: impact on attitudes and food choice. Hollands & Marteau. 2016

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Review finds communicating genetic risks does not change health behaviour

Review finds communicating genetic risks does not change health behaviour

A systematic review led by researchers at the Behaviour and Health Research Unit (BHRU), published on the 16th of March in the BMJ, has found the most conclusive evidence to date that communicating the results of DNA tests has little or no impact on behaviour change, such as stopping smoking or increasing physical activity.

The authors reviewed the results of 18 randomised controlled trials on the effects of communicating genetic risk estimates of a range of diseases for which behaviour change could reduce that risk. The results showed no significant effects of communicating DNA based risk estimates on smoking cessation, diet, or physical activity. There were also no effects on any other behaviours (alcohol use, medication use, sun protection behaviours, and attendance at screening or behavioural support programmes).

These results are timely, given high levels of interest in personalised medicine and increasing use of direct-to-consumer testing for a range of common complex disorders. They mean that existing evidence does not support expectations that such interventions could play a major role in motivating behaviour change to improve population health.

The impact of communicating genetic risks of disease on risk-reducing health behaviour: systematic review with meta-analysis. Hollands, French, Griffin, Prevost, Sutton, King, Marteau. 2016

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