October 16 is World Food Day. We spoke to Marília Prada, a researcher at the Centre for Psychological Research and Social Intervention (CIS-Iscte), who has been investigating individual and contextual factors that affect the adoption of healthier diets.

Marília Prada is a professor at Iscte's School of Social Sciences and researcher at CIS-Iscte. In addition to her experience in developing and validating instruments, her research interests include food perception and eating behavior, social cognition, attitudes, the effect of emotional priming, and consumer behavior.
Marília has developed and worked on projects to understand behavior related to adopting healthy eating. Can you briefly tell us about your research in this area?
My research on food is organized along four main lines. Firstly, I've been interested in the impact of how specific attributes highlighted on food packaging can modulate consumer perception. For example, we have seen that attributes such as "organic origin", "gluten-free" or "no added sugar" can lead people to see products as healthier and less caloric. We have also worked to identify factors that constitute barriers and facilitators of plant-based diets, namely the similarity between meat and the animal that gives rise to it or the perception of meat alternatives. One area in which we have invested a lot is in researching the factors underlying the consumption of high-sugar products. On the one hand, we have focused on individual determinants related to people's ability to reduce their sugar intake, such as knowing the recommended maximum limit or identifying ingredients as sources of sugar. On the other hand, we have explored context-related variables, including analyzing the nutritional quality of product categories on the national market (e.g., breakfast cereals) or even how subtle cues such as music influence the perception of sweetness of different foods.
Finally, I recently joined the team of an international project that aims to promote adherence to the principles of the Mediterranean Diet in university canteens.
What motivated you to study the topic of sugar reduction, as in the Sugar project, and why is this area important in the context of public health?
My interest in the topic arose from my experience as a consumer when I realized that most processed products contain one or more sources of sugar. Most people have no doubts about the high sugar content of some categories of products (such as soft drinks or pastries). However, others are less obvious (e.g., sauces, bread). This issue is highly relevant from a public health point of view since excessive consumption of free sugars has been associated with an increased risk of different chronic diseases.

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Our studies with Portuguese samples suggest that people are aware of these negative consequences and tend to support interventions to reduce sugar consumption. Even so, it is estimated that around 25% of adults in Portugal eat more free sugars daily than the WHO recommends. Solving this problem is highly complex, involving multiple stakeholders in addition to consumers, such as government bodies, the media, and, undeniably, the food industry. Not only must the communication of the nutritional characteristics of food be more effective, but the very composition of many products could be improved to meet current recommendations. One of my favorite quotes in this regard is something like, "It's easier to change products than to change people" (David J. Mela).
CIS-Iscte is a partner in the "MedDietMenus4Campus" project. What is the aim of this project and how does psychology contribute to changing eating habits in the context of this project?
This project is being developed by a European consortium with partners in Portugal, Turkey, and Croatia. The main objective is to analyze the extent to which the menus offered in university canteens respect the principles of the Mediterranean Diet and to identify opportunities for intervention (for example, promoting healthier and more sustainable eating habits by offering more local, seasonal, and plant-based products). The approach is multidisciplinary and includes researchers in nutrition, public health, marketing, and psychology. In my opinion, psychology contributes not only with theoretical perspectives on the different determinants of behavioral change, but also with its methodological approach.

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What results do you expect from this project?
The project foresees the implementation of a set of strategies to promote healthy and sustainable eating, including social marketing campaigns and the availability of a new product ("student bag") in institutions in the three participating countries.
Together with Ispa researcher Magda Saraiva, Marília is coordinating a recently funded project - "LessSugar4Kids". What is the aim of the project?
Excessive sugar consumption in Portugal is even more worrying in children and adolescents, with a high prevalence of overweight and obesity in these age groups. Our previous project included qualitative studies that provided us with relevant clues. For example, a study with university students suggested the need for earlier intervention to promote healthy eating habits. As one 18-year-old participant mentioned, "It's too late for us!". On the other hand, a study with parents of primary school children clearly showed that despite the negative attitude towards sugar - often described as a "poison" or equated with a "drug" - parents have many doubts about the composition of the products they offer their children. In addition, ambivalent beliefs and practices are evident (for example, rewarding good behavior with a sweet treat).
LessSugar4Kids thus aims to promote healthy eating habits in children - particularly reducing sugar consumption. To this end, we will analyze not only the perspectives of parents (or other caregivers) on the topic but also of teachers and the children themselves.
What do you expect from this project?
With this project, we hope not only to contribute to the development of the literature but, above all, to the development of evidence-based strategies that facilitate healthy eating choices for children and their families. Specifically, we will develop tools (a toolkit) so that the topic of healthy eating can be addressed both at home and in the classroom, including educational games with information about the sugar content (and other nutrients) of children's foods and suggestions for alternatives.
Considering your knowledge in this area, how would you suggest that policymakers and health organizations could use scientific data to inform more effective public health campaigns, not only in reducing sugar, but also in promoting healthier consumption habits?
Although I continue to believe in the importance of promoting nutritional literacy skills to facilitate more informed decision-making, I am increasingly defending the need for intervention at a contextual level. There is a huge need to change the food offered in both the retail and catering sectors. For example, international studies show the presence of added sugars in around 75% of processed products. It is, therefore, essential to ensure that the composition of products is reformulated so that they are effectively healthier. It is not enough to lower the sugar content to the threshold that guarantees a green Nutriscore (for example, a famous brand of children's cereals is apparently a good choice because it has lowered the sugar to 22.4 g/100 of product, and an extra 0.1 g would cause the product to be considered to have a high sugar content). Eating behavior is highly complex, and it is essential that we better understand how people process information about food, what (often unfounded) inferences they make from specific attributes highlighted on the packaging, and what motivations are inherent in certain choices to promote healthier habits.
What advice would you give to people who want to make healthier food choices and reduce their sugar consumption, based on the knowledge you've gained from your research?

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A consumer who wants to avoid inadvertently consuming sugar can start by trying to reduce their consumption of highly processed drinks and foods. Training in label reading is also crucial to prevent bias (for example, a light product is not necessarily a low-sugar product; a "no added sugar" product is not necessarily a sugar-free product). Another strategy is to read the list of ingredients to identify synonyms for sugar (e.g., syrups). It's not always easy to implement these strategies, as studies show the existence of over 150 names for sugars. In conclusion, I would like to stress that my position is not to eliminate sugar-rich foods entirely but to make conscious and informed decisions daily, with the consumption of sugar-rich foods occurring in exceptional situations.
World Food Day was established by the United Nations in 1979 to celebrate the creation of its Food and Agriculture Organization. Since 1981, the celebration of this day has followed a specific theme each year. The 2023 edition, under the motto "Water is life, water is food. Leave no one behind.", is dedicated to water and aims to raise awareness of its importance, especially in the context of climate change