Food Culture and Dietary Choice

Work Package Healthy diets and dietary choice

Research Deliverable

Food culture and dietary choice

Introduction

Scotland, in common with many other countries faces a crisis in public health as a result of non-communicable disease of dietary origin (i.e. obesity, type 2 diabetes, cardiovascular disease, & stroke). To achieve healthy balanced diets requires reductions in fat, salt and sugar, and in overall calorie intake. The Revised Dietary Goals for Scotland (2013) highlighted the challenge of achieving population-scale dietary targets where these require changes in intake of individual dietary components, macronutrients or food groups. Although there have been small improvements in the last decade, none of the earlier ‘Targets’ have been met. Added to this is the environmental pressure and impact of current diets, for example food choices, that are contributing to climate change and placing pressure on land use for food production. Sustainable diets not only comprise health and environment, but critically important are socio-cultural and economic aspects of food choices. Whilst food reformulation has a role to play in promoting dietary change, healthier and more sustainable food environments are needed, which includes understanding societal food culture and individual food related behaviours. The goal is to support consumers to achieve beneficial behaviour change towards healthier and more sustainable diets.

Aim of Research

This research targets a number of complementary, interdisciplinary strategies to support changes in food culture, social norms and dietary choices towards ‘sustainable and healthy balanced diets’. Socioeconomic and behavioural approaches will be applied to characterise factors affecting dietary choice and behaviours in different population groups and life-stages, particularly cultural influences. The aim is to explore the potential benefit of innovative interventions to change dietary habits. The studies investigate the role of social networks in food choices, the use of nutritional information and impact of food choice in everyday life in different groups, the influence of parental behaviour on children’s diets, the dehabitualisation of unhealthy dietary choices through changing food preference with repeated exposure, and explore the strategies individuals use to achieve healthier diets than their peers within their socio-demographic group.

This will be achieved through:

A systems modelling approach to better understand influences on food choice, consumer attitudes and beliefs, social networks and effects of policy changes in complex social systems.
Dietary intervention strategies to support healthier habits and food choices through changes in taste preference.
Analysis of dietary and health national datasets.
Understanding the use of nutritional information.

Progress

2021 / 2022

Research activities held over from year 5 and the timely longitudinal COVID-related study were progressed to completion.

The SIMFOOD model, which simulates food choice exploring the impact of the price of meals in choosing a healthy, sustainable diet, was developed and a report drafted. This model extended the underpinning theories around social norms to account for consumer resources and prices.

The lockdowns following COVID were a more drastic intervention than anything planned and revealed the sensitivity of dietary patterns to enormous shocks, not least to the role of social interactions and connections on food choice. Lockdowns have been a natural experiment that will, in time, empirically demonstrate the importance of social isolation. What may be unclear is the importance of an incomplete return to work (and commensurate changes in social interactions) in shaping trends in diet quality. Originally, the SPILLOVER model was meant to look at the consequences for household diets when workplace meals are regulated. The model was adapted to explore scenarios for incomplete return to work and continued isolation. The greater the return to work, the greater the impact of social connectivity and the larger the impact of meal regulation (i.e., improvement in diet quality). However, households without interactions (e.g., no school-aged children and adults who do not go to a workplace) remained unaffected by interventions, which would suggest that a multifaceted approach would be required.

A summary of all modelling work was circulated as a newsletter to key stakeholders to describe the modelling work. It drew together four agent-based models and lessons from them. These lessons included: interventions only lasted as long as they were implemented, then populations tended to return to some habitual norm; interventions that focus on a single driver of diet choice were less effective than those addressing multiple drivers; policies around food costs (e.g. taxes or subsidies) tended to have large, but short(er) term effects than policies to change underlying beliefs; and diet behaviours can spill from one setting to another.

Elsewhere, researchers conducted four waves of surveys and interviews within our study of habits during the first 18 months of the COVID-19 pandemic. All data from diaries, questionnaires and interviews were checked and stored within project databases. Preliminary findings have been disseminated in blogs on the SEFARI website. This is unique longitudinal data following up with our “pre-COVID” study cohort, including assessment of resilience to shocks to the food supply chain, and offering insight into experiences and responses during this unprecedented period.

The starchy carbohydrates study was delivered using the Qualtrics platform and data was collected from 2000 participants, experimentally manipulating message content to deliver a combination of short messages targeting increasing starchy carbohydrates consumption or fruit and vegetable consumption (as controls) in a factorial design. Preliminary analysis was shared with BioSS and then discussed with FSS in an online meeting. This identified possible opportunities to integrate findings into the Eat Well Your Way website, and to replicate this design to target different food types in future.

New work for year 6 included the theoretical modelling of diet shifts towards more sustainable and healthy diet choices. Simple mathematical models of the current understanding of how population groups change diet choices under external and mutual influences were developed drawing on expert opinion and the Agent Based Modelling developed in previous years. Full details of the work can be found here.

2020 / 2021

There was delay to some research activities due to COVID restrictions and consequent disruption to normal life and the behaviours that form the basis of RD3.2.4 research. Some work was replaced, some delayed, and some adapted to enable the effect of the epidemic on food purchasing and consumption to be assessed. Links to FSS were maintained and strengthened, as some areas of work were concluded, and others continued into 2021-2022.

Despite preparatory work, the survey planned for this year could not be conducted due to the pandemic. Activity was instead focussed on construction of four agent-based models to simulate food choices and the role of social networks. Two ABMs modelled reducing meat consumption (MEATNET and DISMAL) and two shifting towards healthier diets and lower greenhouse gas emissions (SIMFOOD and SPILLOVER). The DISMAL model was completed with the scenario of a meat-free day in workplaces. SIMFOOD simulated food choice, exploring the impact of the price of meals on choosing a healthy, sustainable diet (e.g. taxes, incentives). Models suggest that behaviours spill over from one setting to another as individuals interact and start to spread the positive influence of different scenarios. A combination of interventions is likely to have the greatest effect rather than a single action.

Whilst analysis of children’s diets indicated that significant factors in discretionary food intake were parent and child health behaviours and characteristics, habitual behaviour analysis of households with or without children suggests that restrictions on price promotions would be at least as effective for households with children and in some cases more so. The results were presented and discussed at a final meeting with FSS. A paper based on this work has been submitted for publication: "A Longitudinal Study of the Effects of Price and Promotion Incentives on Purchases of Unhealthy Foods: Evidence for Restricting Food Promotions".

With the onset of COVID, the starchy carbohydrate intervention study was postponed and the sugar study repurposed to investigate the effect of the epidemic on food consumption habits and food purchasing in subjects where we already had detailed dietary habit information. Participants completed food and drink diaries to complement baseline data obtained as part of the sugar study, along with dietary questionnaires and semi-structured interviews. Rounds of contact were conducted in April-20, August-20 and January-21. The preliminary findings offer insight into experiences and responses during this unprecedented period, indicating that changes in food habits were generally subtle modifications of existing patterns and behaviours rather than radical changes. The starchy carbohydrate intervention study was rescheduled to 2021-2022. Discussions were reinitiated with FSS with a view to co-design of the study to address priority areas for dietary messaging.

People from income households who achieve a higher diet quality than their peers (positive deviance) were interviewed about their attitudes to food, food-related behaviours and their social and cultural environments. The interviews suggested that neither the cohort nor the respondents recruited from it eat more healthily than their peers. This is because they appear not to belong to the 'socio-demographic subgroup' that was targeted. Many respondents owned their homes, suggesting that their low income does not indicate socio-economic deprivation. Therefore, this research bolsters the case for dietary guidelines being tailored to people’s different socio-cultural contexts. The report was shared with FSS.

2019 / 2020

A variety of methods are being used to understand in more depth food culture and dietary choices, including modelling food related complex social systems, secondary analysis of national, primary data collection and experimental studies.

An agent-based model was built to simulate social interactions between two discrete networks (workplace and home). Norm-based messages in the workplace with information linking meat consumption with health, climate change and animal welfare found that the attitudes of people within individual’s networks influences their likelihood of eating meat. This influence spread from workplace networks to households but cause an unintended consequence of increasing meat consumption by targeting specific groups. An outward facing interface for the model was developed to communicate the findings to non-experts.

Investigating people’s opinions and attitudes regarding front of package nutritional labelling identified distinctive viewpoints, showing that a "one-size-fits-all" approach is unlikely to be effective as the levels of trust, understanding and interest diverged considerably.

Analysis of habitual purchasing of discretionary food items (cakes, pastries and crisps) found past purchasing has a positive effect on the probability of current purchasing. Households purchasing higher quantities of discretionary food were less likely to reduce purchasing with a price increase than household which buy lower amounts. Volume based promotions (e.g. 3 for 2) have a greater effect on the amount purchased than price promotions.

Data analysis shows parents’ smoking, parents’ and children’s TV viewing and age of children are associated with increased frequency of children’s consumption of discretionary food among lower income, SEC and SIMD subgroups. Parents’ physical activities, education and eating 5-a-day fruit/vegetable reduce the frequency of consumption among higher income, SEC and SIMD subgroups. This suggests that different approaches may be needed to narrow health inequalities.

Initial analysis of the repeated exposure sugar study is complete and discussions are underway with FSS about incorporating findings into new ‘Dietary Guidance’. A follow-up pilot study has examined life course consumption of starchy carbohydrates through structured interviews and was to be the basis of an on-line intervention on starchy carbohydrates being designed with FSS input, prior to the COVID-19 outbreak leading to its suspension.

People from income households who achieve a higher diet quality than their peers (positive deviance) were interviewed about their attitudes to food, food-related behaviours and their social and cultural environments. Interviewees were aware of healthy eating but did not seek dietary information. They appeared not to have been seduced by marketing of conveniences foods.

2018 / 2019

Research continued with the aim of achieving greater understanding of food culture and dietary choice. The National Diet and Nutrition Survey was used to analyse the social (e.g. who with), situational (e.g. where) and temporal (e.g. when) aspects of eating meat , which was recently published (Appetite 2019, 138, 1-9). This insight into some socio-cultural aspects of eating meat is being used to inform the agent-based models being developed.

The first model was designed based on influence of social interactions and networks in relation to food choices and was used to explore different norm-based messaging on likelihood of eating meat (e.g. health, environmental, animal welfare). The setting for the model was workplaces and the influence of social networks was incorporated through the interaction of people with those in the workplace and those in their household (e.g. spread of influence of messaging on those in the workplace to others).

The pilot study investigating the opinions and attitudes regarding people’s perceptions of front of package nutritional labelling led to the creation of a final set of statements which represented the diversity of opinion. These were used to collect further data, analysis of which is now underway in order to to identify the aspects of food choice and nutritional information that are rejected by or, on the contrary, shared among the different consumers. This will identify themes that can inform policy makers on nutritional information policies and how to make them potentially more effective.

Elsewhere data analysis has shown that frequency of discretionary food consumption (i.e. foods and drinks which are not necessary to provide the nutrients that the human body requires) rises as children grow, and are higher for children who watch more TV.

Recruitment to the repeated exposure sugar study continues, and exit interviews have been conducted in all five behaviour change dietary groups. The planned follow-up study on habitual bread consumption has been broadened following detailed discussion with Food Standard Scotland and the pilot study now planned covers life span attitudes and habits in relation to starchy carbohydrate consumption more broadly.

2017 / 2018

Based on the framework developed in year 1, an agent based model incorporating complex social settings (e.g. workplace /home) was developed for use in simulating social influence on peoples’ dietary choices. The initial model contains empirical data from national survey datasets (e.g. British Attitudes Survey, National Diet and Nutrition Survey) and is being used to explore the influence that social networks and social interactions can have on the food choices people make.

Opinions and attitudes regarding people’s perceptions on front-of-package nutritional labelling were collected using a technique called Q-methodology. Statements were collected from literature and online sources (1,321 statements) as well as Focus Groups (5 Focus Groups with a total of 32 participants) so as to create an exhaustive list of consumers’ opinions on nutritional labelling. A set of statements (41 statements) was selected to represent the diversity of opinions gathered and a pilot study is under way where participants are asked to rank them in terms of how much they agree/disagree with them.

Work investigating the influences over children’s food choices determined the diet quality index (DQI) score for children using data from the Scottish Health Survey. Parent characteristics, including health behaviours, education and household factors (area deprivation) had an effect on DQI scores and children had a higher DQI if parents were motivated to eat healthily.

Recruitment to the sugar study continued with the first enrolled volunteers completing the 12-week intervention and 3 month and 6 month follow-ups. As part of the strategy to distinguish between the respective roles of habit and preference in determining dietary free sugar consumption, ethical permissions were revised to allow exit interviews with subjects who had completed the whole 9-month study. New work was added to the RD for year 2 to address the phenomenon of positive deviance whereby some consumers on low incomes manage to achieve a higher (nutritional) quality diet than their peers, despite limited resource.

2016 / 2017

Studies are being conducted to explore food cultures and behaviours relating to dietary choices. Current diets are not only unhealthy but are also environmentally damaging therefore we need to know how to change dietary intakes. Understanding how social interactions between people can affect what they choose to eat, as well as the influence of being in different environments, is important. A framework to simulate complex social situations (‘real world’) has been developed to explore food choice, specifically meat consumption, in different scenarios.

The quality of children’s diets currently falls short of meeting Scottish Dietary Targets and these eating habits are likely to persist from childhood into adult life. Understanding the influences on children’s food choices has the potential to suggest new ways of improving children’s diets. Data has been acquired that will allow us to look at the relationships between children’s diet quality and the characteristics of parents and the households in which they live.

Breaking the habit of consuming unhealthy foods and drinks can be particularly difficult given that their inclusion has often been sustained over many years. Supporting individuals to dehabitualise and switch, for example from high-sugar dietary choices to healthier alternatives, could make a significant contribution to reducing caloric intake. A pilot study has been completed with findings evaluated to form the basis for a 12-week behaviour change intervention targeting pre-existing habitual free sugar consumption in one of three domains: (1) discretionary sugar in hot drinks, (2) sugary soft drinks and (3) sugary breakfast cereals.

Future Activities

Research from 3.2.4 relevant to the current priorities of RESAS and Scottish Government will be taken forward in the new SRP 2022/27 in projects RI-B4-01 (Building food and nutrition security in Scotland), RI-B5-08 (Understanding public attitudes and preferences for healthy and sustainable diets) and RI-B5-09 (Pathways to healthy and sustainable diets: identifying facilitators, barriers and avoiding unintended consequences of switching to a more plant-based diet).

Selected Outputs

Selected Publications

2016/17

Eating like there’s no tomorrow: public awareness of the environmental impact of food and reluctance to eat less meat as part of a sustainable diet. (2016) - paper published in Appetite, by Macdiarmid et al

Does real time variability in inhibitory control drive snacking behavior? An intensive longitudinal study, (2017) – a paper published in Health Psychology, by Powell et al.

2017/18

Assessing national nutrition security: The UK reliance on imports to meet population energy and nutrient recommendations. (2018) – paper published in PLOS ONE by Macdiarmid et al

Moving beyond calories and protein: micronutrient assessment of sustainable diets and land use. (2018) – paper published in Global Environmental Change, by de Ruiter et al

2018/19

Attitudes towards, and purchasing of, Scottish beef and beef products in Scotland. (2018) – paper published in Meat Science by Whybrow & Macdiarmid

Healthy and sustainable diets that meet greenhouse gas emission reduction targets and are affordable for different income groups in the UK (2019) – paper published in Public Health Nutrition by Christian Reynolds et al and voted Nutrition Society paper of the month for April 2019

2019/20

Social, temporal and situational influences on meat consumption in the UK population. (2019) – paper published in Appetite by Horgan et al

An Agent-Based Model to Simulate Meat Consumption Behaviour of Consumers in Britain (2019) – paper published in the Journal of Artificial Societies and Social Simulation by Scalco, Andrea et al.

2020/21

Self-reported food intake decreases over recording period in the National Diet and Nutrition Survey (2020) – paper published in British Journal of Nutrition by Whybrow et al

We are what we (think we) eat: The effect of expected satiety on subsequent calorie consumption (2020) – paper published in Appetite by Brown et al

2021/22

Expenditure and nutritional impact of banning the promotion of foods high in fat, sugar and salt in Scotland (2022) – paper published in Frontiers in Nutrition by Revoredo-Giha et al

Longitudinal study of the effects of price and promotion incentives on purchases of unhealthy foods: evidence for restricting food promotions (2022) – paper published in BMJ Nutrition by Kopasker et al

Effect of different foods on energy intake within and between individuals (2022) – paper published in Eur J Nutr by Horgan et al

The role of healthy diets in environmentally sustainable food systems (2021) – paper published in Food and Nutrition Bulletin by Clark et al

Reports

FAO/WHO International Committee: Development of UN dietary guiding principles for sustainable and healthy diets (July 2019): FAO, Rome.

Macdiarmid JI (2019) Book Chapter: Healthy and sustainable diets. In: Healthy and Sustainable Food Systems, Routledge. Editors: Mark Lawrence and Sharon Friel

Newsletter - Sustainable Diets: modelling individual social and situational influences on dietary choices

Briefing note – Theoretical modelling of diet shifts towards more sustainable and healthy choices

Presentations (academic)

Italian Association of Agriculture and Applied Economics International Conference. Invited keynote lecture: The impact of changing diets on health and the environment - where do we need to go? Florence, Italy (June 2019).
Global Academy of Agriculture and Food Security. Invited keynote lecture: Achieve sustainable diets: eating is a complex social phenomenon. University of Edinburgh, Edinburgh (June 2019).
UK Society for Behavioural Medicine. Invited keynote lecture. The global food system is broken: What can we do to move towards more sustainable diets? Bath (Jan 2020).
Future Food Conference. Invited talk. What protein sources will we be consuming in the future:what impact will these dietary trends have on human health? London, (Nov 2019).
Alpro Foundation. Invited talk. Are sustainable diets healthy diets? University of Leeds. (Nov 2019)
LEAP conference (Wellcome Trust). Poster: Modelling the impact of social marketing campaigns to reduce meat consumption: Results from an agent-based model. University of Oxford (Dec 2019)
Invited seminar. Modelling the impact of interventions aimed at reducing meat consumption using agent-based modelling. University of Glasgow (Oct 2019)
European Health Economics Association (EuHEA) Conference 'Longitudinal analysis of parents’ influence on children discretionary food choices', Católica Business School Porto, (September 2019).

Presentations (KE – public engagement events)

Pint of Science series: Waiter, why is there a fly in my soup? Aberdeen (May 2019)

Blog posts

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Food Culture and Dietary Choice