Downsizing: using environmental prompts to understand healthy portion control and appropriate food servings in children, adolescents and caregivers

National survey data for the UK shows that portion sizes of some energy dense foods (foods more than 2.5kcal/g) are associated with overweight and obesity. Habitual and frequent consumption of items which are high in energy density contributes to a high total energy intake. In particular intakes of some sugar sweetened drinks, savoury snacks, confectionery and cakes are associated with higher body weights. The term "portion distortion" is now commonly used to reflect changes in portions of foods offered outside the home over the last 20 years. This refers to both the supersizing of common meal and snack items such as burgers, pizzas, soft drinks, crisps and sweets and the additional physical activity required to accommodate these large amounts to achieve energy balance. Supersizing and changes to pre-packaged quantities are important since consumers rely on unit size to guide intake. Increased portion sizes alter how much is eaten in two ways - directly by providing more, consumers (including children) eat more and indirectly by presenting larger amounts as "normative", so this is what consumers expect to drink or eat. Thus the first carbonated sugar sweetened beverage volume was typically 8 fluid ounces (236ml) but today bottles are available in 12 fluid ounce (~375ml) for a single serving or greater. These changes suggest to the consumer that the typical or normal serving size is higher now than before. The "portion size effect" where more is eaten or identified as an appropriate serving when more is offered has been confirmed by research. For example large scale survey methods (e.g. the EUFIC report on 13,000 consumers in Europe) and small scale laboratory experiments confirm a significant and reliable effect of portion size on food intake or self selected serving. The portion size effect has been seen in adults and children. However since children and adolescents learn about the appropriate portion size from what it served to them along with satiety responses developed to these foods over time, establishing appropriate portions is modifiable through learning. Learning is the key psychological process by which children understand culturally appropriate food habits, including meal and snack frequency, types and amounts of foods within their home environment. This proposal sets out to challenge the portion size effect by testing a variety of environmental strategies to "downsize" portions offered to infants and selected by pre-schoolers and adolescents. The first study will record typical portion sizes of high energy snacks offered to infants aged 24-36m then test the effect of replacing or reducing portions served of these foods within a pilot randomised control trial (RCT). The second study will involve systematically changing meal item amounts served in nurseries using variety and palatability to offset the portion size effect on self served amounts in pre-schoolers. The third study examines the feasibility and acceptability of using "nudging" to promote smaller portions of snacks in adolescents using social media and digital technologies for sharing social norms of portions. The fourth study uses direct observations in households with infants and pre-schoolers to identify packaging solutions matched to family needs to adjust portion sizes for family members. The final part of the project will provide evidence to recommend ways that stakeholders such as families, childcare workers, healthcare professionals, industry and policymakers can apply downsizing strategies to support healthy portion control. The evidence based strategies will include ways to use smart packaging, small containers and visual cues to reduce intake of HED snacks and meal items; and to encourage intake of LED foods, high in dietary quality such as fruits and vegetables.

The portion size effect (PSE) is robust, reliable and observed across age groups. Larger amounts of foods are eaten when larger amounts are offered. It is assumed that without compensatory behaviours, increased portion size of energy dense foods contribute to the rising prevalence of overweight and obesity. If children learn about portion sizes of high energy dense (HED) foods through experiences shaped by parents, by adolescence these habits influence weight status. The aim of the proposed research is to test the hypothesis that repeated exposure, visual cueing, nudging and packaging can be used to reduce intake of HED items and increase intake of fruits and vegetables in children, adolescents and families. Furthermore if HED items are replaced or reduced in favour of fruits and vegetables, it is predicted that there will be no compensatory behaviours. To achieve this aim, 5 workpackages (WP) have been developed. WP1 uses observational data to investigate typical portion sizes of key HED snacks in 24-36m old pre-school children; then families involved in the observational research will be invited to take part in an intervention to test the efficacy of replacement or reduction so that fruits and vegetables replace HED items or supplement smaller portions of HED items. WP2 develops these ideas further by testing a series of systematic manipulations of HED meal items and LED components using variety and palatability to offset the PSE in pre-schoolers. The objective of WP3 is to test the efficacy of nudging on serving size of target items using online social media techniques in adolescents. The objective of WP4 is to use design concepts and personas to produce evidence of the consumers who will respond to changes in packaging, and to suggest packaging improvements to industry to support consumer choice. WP5 will bring together evidence from all studies to provide recommendations for downsizing to benefit a variety of stakeholders including families.

Pathways to impact have been planned so that beneficiaries from the research will include families, nurseries, food companies and policy makers. Families who seek to achieve a healthy, balanced diet will benefit because the research promises to deliver portion control advice for high energy density (HED) foods appropriate to the age and stage of their children. This is particularly needed by parents of young children who seek advice for portion control but have little guidance on how much to provide their infants in the early years. It is not realistic to ask or expect parents to avoid offering HED items to their infants, but guidance on appropriate sizing is warranted and achievable. Nurseries who wish to promote healthy eating can use successful downsizing strategies within the childcare setting to support the efforts of families to enable "me-sized" snacks and meals to be offered and eaten.
Food companies will gain insight into the ways in which foods can be packaged and labelled to facilitate healthy portion control by families. This is strategic for companies who produce HED foods/beverages and who have signed up to the UK Department of Health Responsibility Deal. Specifically, those companies who have pledged under F4 "Calorie reduction" will benefit since this research will provide evidence to support the development of smaller portion sizes of existing products and menu items to enable companies to meet this pledge. Food companies could use data from the household observations to match prototype repackaging to the needs of families and could benefit from the results of the design concepts to enable innovative products to be relabelled and formulated to suit appropriate portion control.
Policy makers will benefit from the experimental evidence to underpin downsizing strategies to match policy recommendations for healthy portion control. Policy makers are involved in providing guidance to consumers on achieving a healthy, balanced diet. Acquiring healthy portion control is part of this especially in the early years when eating habits are established. Change4Life has promoted "me-sized" snacks and meals and the present research will provide the opportunity to test the efficacy of downsizing and matching portions to the age and stage of family members. Downsizing interventions, if successful, could be used widely to promote health behaviour change especially with regard to increasing fruit and vegetable intake and reducing intake of high energy dense items.
This research will advance our understanding of portion control in children and adolescents. The design, development and delivery of simple interventions which are relevant to households with varying budgetary concerns will help to meet targets to reduce energy intake, whilst being sensitive to the needs of children as they grow. The main contention of this research is that children will adapt to environmental cues which prompt intake, they are responsive to social norms for portion control and can learn to select for themselves "me-sized" meals and snacks since this behaviour is acquired, but that they will not necessarily compensate for changes in portions. The studies have been developed to combine public health, behaviour change and design components. They have been devised to combine individual observation, intervention and household observations to tackle the impact of downsizing. It is important to test the efficacy of downsizing since this is a simple and obvious solution to the portion size effect and the studies will provide a set of recommendations for increasing F&V intake, adjusting and reducing portion sizes of HED foods to suit the age and stage of the child within each household.