The neurobiology behind food choice: what makes us eat too much?
Despite health information, education and taxes on harmful foods, the rates of obesity and non-communicable diseases remain high. As a result, governments worldwide are looking to improve citizens’ health by nudge interventions, small yet relevant behavioural stimuli that aim to change what people choose to eat. However, to generate effective recommendations, it is central to comprehend the determinants of dietary choices. Towards this goal, the EU-funded NUDGE-IT (The Neurobiology of Decision-Making in Eating – Innovative Tools) project brought together leading European experts in the field to determine effective strategies for adhering to nutritional guidelines. “The overall aim of NUDGE-IT was to better understand decision-making in food choice and to build predictive models to contribute to improving public health policy,″ explains project coordinator Prof. Gareth Leng. Food choices are influenced by cultural and social pressures, cognitive factors as well as familial, genetic and epigenetic factors. In addition, food marketing and labelling, economic factors and the perception of healthy eating play a role in dietary habits. “Some factors are likely to be barriers to the efficacy of certain types of policy intervention or raise concerns about negative consequences for some sectors of society,″ outlines Prof. Lang. NUDGE-IT worked to translate insights from basic research into policy recommendations, bridging the gap in understanding between mechanistic insight and translational studies in humans. In this context, scientists integrated behavioural and observational studies with neurobiological data studies to educate stakeholders on dietary recommendation policies. Determinants of food choices The project made a number of interesting observations including the powerful influence of homeostatic and hedonic or reward brain mechanisms on food consumption and body weight. Interestingly, scientists discovered that both fat mass and bone influence overall food intake, while signals from the gut and fat mass seem to additionally affect the reward pathways. This may have potential implications in efforts to reduce the bone-to-mass index across the population. Furthermore, deficiency of a specific nutrient may drive an increase in food intake to counterbalance the loss, forcing an inevitable increase in energy intake. Although body weight is considered to be 80 % heritable, emerging evidence indicates that stress and impaired nutrition during gestation and in early post-natal life seem to have lifelong repercussions on physiology and metabolism. Undoubtedly, the metabolic status of the mother during gestation influences the brain dynamics of the foetus while overnutrition in early life not only produces weight gain, it also induces a lifelong change in food choice. Nonetheless, NUDGE-IT data suggest that interventions in children’s diet to promote healthy eating can be very effective. This probably reflects their rapid growth rate and suggests a dynamically regulated homeostatic pathway. The neurobiology of eating habits Undoubtedly, when it comes to food, decision-making is tightly linked to activity in certain brain regions. Alterations in these areas may be associated with the behavioural changes that lead to obesity. Based on this, NUDGE-IT employed neuroimaging modalities to study the neural correlates and processes implicated in the behaviour towards food. Researchers identified the neural circuits involved in food valuation and selection, further identifying brain sub-regions that control appetite. Interestingly, they discovered a novel association between individuals’ physiological and psychological status and food choice. A more holistic view of food choice mechanisms was made possible by mathematical modelling, building a framework towards evidence-based dietary policies. “We must continue to combine mechanistic and translational studies and tackle compliance issues by tailoring nudging policies to specific populations,″ concludes Prof. Leng.
Keywords
NUDGE-IT, food, reward pathway, neurobiology, weight
