Perceptual salience influences food choices independently of health and taste preferences

Why Acute Undernutrition? A Qualitative Exploration of Food Preferences, Perceptions and Factors Underlying Diet in Adolescent Girls in Rural Communities in Nigeria

BACKGROUND

Adolescent girls are nutritionally vulnerable due to their rapid growth and increased nutrient requirements. Nigeria has the sixth-largest population in the world. This study qualitatively explored the food preferences, perceptions of nutritive value and factors underlying food consumption of adolescent girls in rural communities in Nigeria.

METHODS

The data were collected via the free listing of foods and focus group sessions conducted in the Hausa language with 48 unmarried adolescent girls. The discussions were audio-recorded, transcribed, translated into English, and analyzed using a deductive thematic framework.

RESULTS

The mean age of the respondents was 13.0 ± 2.7, and almost half (48%) had a primary school education. A total of 19 and 23 foods were identified as preferred, and perceived as nourishing, respectively. The top 10 foods present on both free lists overlapped considerably in terms of cognitive salience. The focus group themes included nutrition knowledge, food preferences, autonomy, household food allocation, courtship practices, and agricultural landscapes and economic access. The participants had minimal knowledge of nutrients and food groups, and their preferred foods were limited in diversity. The key factors in food preferences were desirable health effects, sensory attributes, and the contribution of foods to a desirable body image for marriage. Household food choices depended on parents. Thus, a desire for independence was an incentive for early marriage, mostly at 13 to 17 years. Gender inequities in household food distribution (quantity) and animal protein intake were reported. The participants believed that boys need more food for strength to impregnate girls. As part of a courtship practice, the girls received gifts of animal source foods from potential suitors. The food options were limited by financial challenges and low agricultural diversity.

CONCLUSION

To interrupt the cycle of inadequate food consumption and undernutrition in these adolescent girls, policy makers need to promote nutrition education and address the underlying determinants of inequitable access to nutritious foods.

A value accumulation account of unhealthy food choices: testing the influence of outcome salience under varying time constraints

People often engage in unhealthy eating despite having an explicit goal to follow a healthy diet, especially under certain conditions such as a lack of time. A promising explanation from the value accumulation account is that food choices are based on the sequential consideration of the values of multiple outcomes, such as health and taste outcomes. Unhealthy choices may result if taste is considered before health. We examined whether making a health outcome more salient could alter this order, thereby leading to more healthy choices even under time pressure. Two studies examined the time-dependent effect of outcome values and salience on food choices. Participants first completed priming trials on which they rated food items on healthiness (health condition), tastiness (taste condition), or both healthiness and tastiness (control condition). They then completed blocks of binary choice trials between healthy and tasty items. The available response time was manipulated continuously in Study 1 (N = 161) and categorically in Study 2 (N = 318). As predicted, results showed that the values of health and taste outcomes influenced choices and that priming led to more choices in line with the primed outcomes even when time was scarce. We did not obtain support for the prediction that the priming effect is time-dependent in the sense that primed outcomes are considered before non-primed outcomes. Together, these findings suggest that increasing the value and salience of a health outcome may be effective ways to increase healthy choices, even under poor conditions such as time pressure.

Hedonic response sensitivity to variations in the evaluation task and culinary preparation in a natural consumption context

Hedonic measurements in the frame of consumer tests of foods are prone to many different biases and the validity of test designs has been subject to much research with special emphasis on the role of context. While bringing elements of natural consumption context to the testing conditions is generally seen as an improvement, other aspects of the test design such as the task format have received little attention. In particular, the influence of analytical questions on hedonic responses has been studied in standardized contexts only. This study aimed to assess whether synthetic and analytical evaluation tasks result in different hedonic responses when the test is conducted in a natural consumption context. Bread and pizzas with different degrees of culinary preparation (homemade, readymade, and a combination of the two) were tested on three separate days in a university cafeteria. Overall liking scores of the bread and the three different pizzas were obtained either with a synthetic (hedonic question only) or with an analytical task (hedonic question plus intensity attributes). Care was taken to avoid any other changes to normal eating conditions, notably by recruiting on the spot only those customers who had spontaneously chosen pizza as part of their lunch. Liking scores of the homemade pizza were lower with the analytical task while the scores of the other two pizzas did not change significantly. Moreover, different rankings of the pizzas were obtained when the data were analyzed separately for each evaluation task format. The synthetic evaluation task would have led to the conclusion that the homemade pizza was the best liked and the readymade being the least liked, while the analytical evaluation task would have led to the conclusion that the “mixed” pizza would be liked significantly more than the other two. The effect of the task format (i.e., lower scores with the analytical task) was more pronounced when participants reported they had spent more time in the queue. These results strengthen the view that the task is part of the evaluation context and must be carefully considered when one wishes to design ecologically valid consumer tests.

Contextual and Individual Variables as Predictors of Energy-Dense Meals in Food Choices

Diets based on meals that provide a large amount of energy and consumed frequently often increase the rate of growth of the body mass index (overweight or obesity) and, in turn, the risk of suffering from non-communicable diseases. In order to make a food choice, it is necessary to search for foods in the environment, taking into account physical and social variables (contextual variables) which, together with individual variables, delimit the situation of food selection. The objective of this study was to evaluate the effect of social facilitation, portion size, salience of food, and food preference or rejection on the selection of energy-dense foods by young college students. To do so, we performed a factorial experiment in which unaccompanied and accompanied participants (levels of social facilitation) as they went through the process of choosing from different options of main dishes, beverages, and desserts then noted the reasons for their selection (preference or rejection of the food). Results showed significant differences between the group of accompanied participants and salience of food in the selection of the energy-dense main dishes and desserts (pizza, spaghetti, and chocolate cake). A significant relationship was also identified between accompanied participants, hedonistic/sensory reasons (food preference or rejection category), and salience of food in the selection of the energy-dense main dishes. In conclusion, key findings of the variables that constitute the situation that predicts the selection of energy-dense foods have emerged from this study, when participants and the given level of social facilitation (in this case, being accompanied) were faced with the conditions of the food salience of the meals of their preference regarding its taste and appearance.

Five weeks of intermittent transcutaneous vagus nerve stimulation shape neural networks: a machine learning approach

Invasive and transcutaneous vagus nerve stimulation [(t)-VNS] have been used to treat epilepsy, depression and migraine and has also shown effects on metabolism and body weight. To what extent this treatment shapes neural networks and how such network changes might be related to treatment effects is currently unclear. Using a pre-post mixed study design, we applied either a tVNS or sham stimulation (5 h/week) in 34 overweight male participants in the context of a study designed to assess effects of tVNS on body weight and metabolic and cognitive parameters resting state (rs) fMRI was measured about 12 h after the last stimulation period. Support vector machine (SVM) classification was applied to fractional amplitude low-frequency fluctuations (fALFF) on established rs-networks. All classification results were controlled for random effects and overfitting. Finally, we calculated multiple regressions between the classification results and reported food craving. We found a classification accuracy (CA) of 79 % in a subset of four brainstem regions suggesting that tVNS leads to lasting changes in brain networks. Five of eight salience network regions yielded 76,5 % CA. Our study shows tVNS’ post-stimulation effects on fALFF in the salience rs-network. More detailed investigations of this effect and their relationship with food intake seem reasonable for future studies.

Digital Nudging for Online Food Choices

When people search for what to cook for the day, they increasingly use online recipe sites to find inspiration. Such recipe sites often show popular recipes to make it easier to find a suitable choice. However, these popular recipes are not always the healthiest options and can promote an unhealthy lifestyle. Our goal is to understand to what extent it is possible to steer the food selection of people through digital nudging. While nudges have been shown to affect humans' behavior regarding food choices in the physical world, there is little research on the impact of nudges on online food choices. Specifically, it is unclear how different nudges impact (i) the behavior of people, (ii) the time they need to make a decision, and (iii) their satisfaction and confidence with their selection. We investigate the effects of highlighting, defaults, social information, and warnings on the decision-making of online users through two consecutive user studies. Our results show that a hybrid nudge, which both involves setting a default and adding social information, significantly increases the likelihood that a nudged item is selected. Moreover, it may help decreasing the required decision time for participants while having no negative effects on the participant's satisfaction and confidence. Overall, our work provides evidence that nudges can be effective in this domain, but also that the type of a digital nudge matters. Therefore, different nudges should be evaluated in practical applications.

A nudge in the right direction: the role of food choice architecture in changing populations' diets

Populations' diets typically fall short of recommendations. The implication of this on ill health and quality of life is well established, as are the subsequent health care costs. An area of growing interest within public health nutrition is food choice architecture; how a food choice is framed and its influence on subsequent food selection. In particular, there is an appeal to manipulating the choice architecture in order to nudge individuals' food choice. This review outlines the current understanding of food choice architecture, theoretical background to nudging and the evidence on the effectiveness of nudge strategies, as well as their design and implementation. Interventions emphasising the role of nudge strategies have investigated changes to the accessibility, availability and presentation of food and the use of prompts. Empirical studies have been conducted in laboratories, online and in real-world food settings, and with different populations. Evidence on the effectiveness of nudge strategies in shifting food choice is encouraging. Underpinning mechanisms, not yet fully explicated, are proposed to relate to salience, social norms and the principle of least effort. Emerging evidence points to areas for development including the effectiveness of choice architecture interventions with different and diverse populations, and the combined effect of multiple nudges. This, alongside further examination of theoretical mechanisms and guidance to engage and inspire across the breadth of food provision, is critical. In this way, the potential of choice architecture to effect meaningful change in populations' diets will be realised.

Three minutes to change preferences: perceptual fluency and response inhibition

Perceptual fluency and response inhibition are well-established techniques to unobtrusively manipulate preference: objects are devalued following association with disfluency or inhibition. These approaches to preference change are extensively studied individually, but there is less research examining the impact of combining the two techniques in a single intervention. In short (3 min) game-like tasks, we examine the preference and memory effects of perceptual fluency and inhibition individually, and then the cumulative effects of combining the two techniques. The first experiment confirmed that perceptual fluency and inhibition techniques influence immediate preference judgements but, somewhat surprisingly, combining these techniques did not lead to greater effects than either technique alone. The second experiment replicated the first but with changes to much more closely imitate a real-world application: measuring preference after 20 min of unrelated intervening tasks, modifying the retrieval context via room change, and generalization from computer images of objects to real-world versions of those objects. Here, the individual effects of perceptual fluency and inhibition were no longer detected, whereas combining these techniques resulted in preference change. These results demonstrate the potential of short video games as a means of influencing behaviour, such as food choices to improve health and well-being.

Implicit food odour priming effects on reactivity and inhibitory control towards foods

The food environment can interact with cognitive processing and influence eating behaviour. Our objective was to characterize the impact of implicit olfactory priming on inhibitory control towards food, in groups with different weight status. Ninety-one adults completed a modified Affective Shifting Task: they had to detect target stimuli and ignore distractor stimuli while being primed with non-attentively perceived odours. We measured reactivity and inhibitory control towards food pictures. Priming effects were observed on reactivity: participants with overweight and obesity were slower when primed with pear and pound cake odour respectively. Common inhibitory control patterns toward foods were observed between groups. We suggest that non-attentively perceived food cues influence bottom-up processing by activating distinguished mental representations according to weight status. Also, our data show that cognitive load influences inhibitory control toward foods. Those results contribute to understanding how the environment can influence eating behaviour in individuals with obesity.