Alice Porter discusses her PhD research on age-appropriate portion sizes for preschool aged children
Portion size is the amount of food and/or drink served to or eaten by someone. We know from the research that getting portion sizes right is important for child growth. Serving the right amount of food and drink will help children eat a healthy balanced diet, for healthy growth (1). On the other hand, if children regularly eat portion sizes that are too large, this can lead to excessive weight gain (2), which can then lead to health problems in later life (3).
What was my PhD research about?
My PhD research looked at whether there is suitable portion size guidance available for caregivers who feed preschool children (e.g., parents, carers, childcare staff), how caregivers make decisions about how much to serve their preschool children, and what factors might influence how much preschool children eat at meal and snack times.
What my research involved
I firstly reviewed the existing evidence and literature conducting a systematic review of online portion size guidance resources (such as online leaflets, websites and guideline documents) that aimed to inform caregivers about the recommended portion sizes for preschool children. I did this by searching Google and asking experts and then collating and comparing the resources.
After collating the portion size guidance resources, I showed them to 27 first-time parents living in the UK, who had a 1-2-year old child. I asked the parents in online interviews whether they recognised or used any of the resources, what their thoughts were about the format, content, and design of the resources and how they decided the portion sizes to serve their child.
I also looked at data from a large national survey, which collects information about what, how much, where and when children eat (National Diet and Nutrition Survey). I analysed the data to see what influences how much children eat. Factors I explored included the environment in which children eat (e.g., home, childcare, out-of-home), who they eat with, whether they are sitting at a table or watching whilst eating, and how these may be linked to eating larger meals and snacks .
What I found
I found many online portion size guidance resources, which provide portion size recommendations to caregivers feeding preschool children (22 in fact!). Some of the resources recommended healthy meals to serve to preschool children with the recommended portion sizes for each food in the meal provided. Other resources presented recommended portion sizes for lots of different foods in each food group (starchy, dairy, protein, fruit and vegetables). However, the recommended portion sizes were sometimes not the same across different resources. This was particularly true for foods in the dairy, starchy and protein food groups, and for lunch and dinner time meals.
After showing first-time parents a number of the guidance resources, it was clear that although the resources were freely available online, parents hadn’t seen or used them before. This was because parents didn’t use guidance to decide the portion sizes to serve their preschool child. Instead, they used the size of plates and bowls (often ones for children), the size of food packets and the experience they had gained from feeding their child every day. Parents felt they didn’t need to rely on guidance because they had learned how much their child eats on a meal-to-meal basis and wanted to be guided by their child. Parents also expressed they weren’t concerned about their child eating too much, rather they wanted to ensure their child ate enough. Parents did say they looked for feeding advice online and via other sources when weaning (introducing children to solid foods at around six months old). When parents looked for guidance, they wanted it to be from a trusted source (such as the NHS) and also be short, concise, bold, visual and easy to access.
After analysing the survey data, I found the food environment could affect the portion sizes preschool children consumed. For example, when children ate in restaurants, cafes and at childcare they ate larger meals and snacks. Preschool children on average ate 90 calories more in restaurants and cafes compared to when they ate at home. Children also ate larger meals and snacks when they ate with family members and friends (suggesting social influence could be a factor) and when they ate sitting at a table. Larger portions were also consumed whilst watching TV, compared to not watching TV.
Three take home messages
• Portion size guidance resources have been disseminated online but have not reached parents, nor are they the most effective way to teach parents about the importance of serving age-appropriate portion sizes for their preschool children.
• Future strategies should consider providing guidance about age-appropriate portion sizes to first-time parents during their child’s first year, when parents are receptive to feeding advice. The delivery of guidance should line up with parental motivations, preferences and existing feeding practices.
• The environment in which preschool children eat in is important to consider when promoting age-appropriate portion sizes.
I plan to use the learning from my PhD to contribute to new and important childhood obesity research. I plan to do further work with parents and health professionals to develop useful and accepted forms of feeding advice and conduct further research into the influence of the food environment on eating behaviours in children.
Alice Porter is now working as a Research Associate at the University of Bristol.
(1) Nicklaus S. The Role of Dietary Experience in the Development of Eating Behavior during the First Years of Life. Ann Nutr Metab. 2017;70(3):241-245. doi:10.1159/000465532
(2) Syrad H, Llewellyn CH, Johnson L, et al. Meal size is a critical driver of weight gain in early childhood. Sci Rep. Jun 20 2016;6:28368. doi:10.1038/srep28368
(3) Koletzko B, Godfrey KM, Poston L, et al. Nutrition During Pregnancy, Lactation and Early Childhood and its Implications for Maternal and Long-Term Child Health: The Early Nutrition Project Recommendations. Ann Nutr Metab. 2019;74(2):93-106. doi:10.1159/000496471