Orofacial reactivity to the sight and smell of food stimuli. Evidence for anticipatory liking related to food reward cues in overweight children

Whether food liking may be a risk factor of overconsumption and overweight/obesity remains a controversial issue. So far, most studies used subjective reports to assess consummatory behavior, approaches that might overlook subtle or implicit hedonic changes to sensory properties of foods. Therefore, we used a cue-exposure approach by recording different measures of hedonic processes (orofacial reactivity, self-rated pleasantness, food preference) in 6-11 years old overweight (n=20) and normal-weight (n=20) children. Children were exposed to the smell and sight of high and low-energy density food stimuli and to non-food stimuli during pre- and post-prandial states. Their facial and verbal responses were videotaped and parent's reports of children's eating styles and appetitive traits were collected using the Children's Eating Behavior Questionnaire (CEBQ). Results showed that orofacial reactivity, as an objective measure of anticipatory liking, was more discriminative than self reports, with overweight children displaying more lip sucking than normal-weight children when exposed to high energy food pictures and to food odorants. Orofacial reactivity to food cues was also associated with BMI and children's eating styles (food responsiveness, emotional overeating, and desire to drink). Finally, overweight children classified more frequently non-food odorants as members of the food category during the pre-prandial state than during the post-prandial state, suggesting a possible influence of affective/motivational bias on odor categorization. Our findings suggest that orofacial responsiveness may be relevant to assess the sensitivity to energy-dense food reward cues in overweight children and for signaling, as an index of anticipatory liking, a potential risk for the development of overweight/obesity.     

Facilitating or undermining? The effect of reward on food acceptance. A narrative review

Using rewards in child feeding is commonplace and viewed as effective by parents, although some express concern about using ‘bribery’. Psychological and economic theorists emphasize the beneficial effects of rewards in enhancing performance, although, there is evidence that the offer of rewards undermines intrinsic motivation and decreases enjoyment of the rewarded task. In the food domain, results have been mixed, but this may be explained, at least partly in terms of the measured outcome (liking vs intake) and the initial level of motivation towards the target foods (liked vs disliked). Where intake is the outcome, rewards have had broadly positive effects, but when it is liking, rewards can have negative effects if the target food is already liked. Another issue concerns the type of reward offered. While offering food as a reward appear to be universally negative, there is evidence to suggest that non-food tangible rewards (e.g., stickers), or non-tangible rewards (praise) can be highly effective in encouraging children to taste new or less liked foods sufficiently often to benefit from the ‘mere exposure’ effect. We suggest that the judicious use of rewards may facilitate children's acceptance of healthy foods.     

The relationship between child and parent food hedonics and parent and child food group intake in children with overweight/obesity

Many factors influence children's dietary intake, including children's and parents' food hedonics (liking), and parent intake. This secondary data analysis studied the relationship between child and parent liking, and parent intake and child intake of fruits, vegetables, low-fat dairy, snack foods, and sweetened beverages in 4- to 9-year-old overweight/obese (body mass index ≥85th percentile) children presenting for obesity treatment (September 2005 to September 2007) in Providence, RI. One hundred thirty-five parent-child pairs, with complete baseline dietary (3-day food record) and food group hedonic data were included. Hedonic ratings were mean ratings using a 5-point Likert scale (lower scores represented greater liking of a food group). Children were aged 7.2±1.6 years, 63.0% girls, 12.6% African American, and 17.8% Hispanic, with a mean body mass index z score of 2.3±0.6. Total servings consumed by children over 3 days were: fruits 2.7±3.2, vegetables 3.4±2.5, low-fat dairy 2.4±2.1, snack foods 5.9±4.2, and sweetened beverages 2.7±3.1. After demographic and anthropometric variables were controlled, parent intake was positively related (P<0.05) to child intake of all food groups except sweetened beverages. Child liking was only significantly (P<0.05) related to child intake of vegetables. In young children with obesity/overweight, parent intake was consistently related to child intake. Changing parent intake may be important in helping to change the dietary intake of young children with overweight/obesity.     

Increasing food familiarity without the tears. A role for visual exposure?

Research has established the success of taste exposure paradigms as a means of increasing children's acceptance, and liking, of previously unfamiliar or disliked foods. Yet, parents report that they tend to avoid the stress associated with repeatedly offering their children foods that are likely to be rejected. Given that successful taste exposure programmes often enhance children's familiarity with a food's appearance, as well as its taste, this article reviews the potential for exposure interventions that do not require repeated tastings to bring about positive attitude changes towards healthy foods. Recent evidence from studies that expose toddlers to picture books about fruit and vegetables suggest that familiarity with the origins and appearance of unfamiliar foods might increase children's willingness to accept these into their diets.     

Food branding influences ad libitum intake differently in children depending on weight status. Results of a pilot study

Environmental changes have facilitated the rapid increase in childhood obesity. One such change is increased presence of food marketing which promotes intake of high-fat, energy-dense foods. This study tested the hypotheses that overweight (OW) children are more sensitive to the intake-enhancing effects of food branding than non-OW children, and that the relationship between weight status and intake of branded foods is mediated by level of food brand awareness. Forty-three non-OW (n = 23) and OW (n = 20) children from diverse ethnic backgrounds participated in four dinnertime visits to test their intake of meals where food brands were present (“branded”) or absent (“unbranded”). Food brand awareness was assessed by testing children's abilities to match food brand logos with correct foods and name specific brands from recall. Weight and height were measured on the first visit to determine BMI z-score and weight status. OW children consumed significantly more energy per meal than non-OW. Child age and brand awareness were positively associated. OW children consumed an additional 40 kcal in branded vs. unbranded meals whereas non-OW children consumed 45 kcal less in branded meals. Overweight children showed greater responsiveness to food branding, and they may be at risk in environments that are highly inundated with messages about food.     

Positive- and negative peer modelling effects on young children's consumption of novel blue foods

Objective: The effects of positive- and negative peer modelling on children's consumption of a novel blue food, presented in each of four snack meals during an “activity” day, were evaluated. It was predicted that: (i) novel food consumption would increase after positive modelling, but decrease after negative modelling; (ii) modelling effects would generalise to a second novel blue food when participants were alone when they ate their snack; (iii) that positive modelling would reverse the effects of negative modelling. Design: A mixed design was employed with random assignment to either Groups A, B, or C (equal numbers of males and females per group). Within groups, each participant received the novel food on four snack occasions. Group A received positive modelling of blue food consumption on the first and third occasions, but were alone when they received the foods on the second and fourth occasions; Group B had negative modelling on the first occasion, positive modelling on the third, and ate alone on the second and fourth; Group C ate alone on all four occasions. To measure generalisation, an additional blue food was presented in all second and fourth “alone” occasions. Participants: Thirty-five 5–7-year olds took part in Study 1, and 44 3–4-year olds in Study 2. Results: All main predictions were confirmed except that positive peer modelling did not reverse the effects of negative modelling in the 3–4-year olds. Conclusion: Negative peer modelling inhibits novel food consumption, and its effects are particularly difficult to reverse in younger children.     

Adiposity is not associated with children's reported liking for selected foods

It is often assumed that heightened liking for energy-dense foods contributes to the development of obesity, however previous findings on the association between adiposity and liking among common foods are inconclusive in adults and there is limited research in children. Therefore the present study assessed the association between adiposity and liking for fatty or sugary foods, fruits and vegetables in children. A community sample of children aged 7–9 years (N = 366) were recruited as part of the Physical Exercise and Appetite in CHildren Study (PEACHES). Anthropometric measurements (BMI- and waist-SD scores, fat mass index) were taken alongside self-reported liking for a list of fatty or sugary foods, fruits and vegetables. Regression analyses were used to predict liking from continuous adiposity measures (BMI- and waist-SD score, fat mass index). Linear trend analysis was used to assess the patterning of liking across weight categories. Vegetables were liked less than fatty or sugary foods or fruit, but there was no difference between liking for fruit and for fatty or sugary foods. Boys had a higher liking for fatty or sugary foods than girls, although sex-by-adiposity interactions were not significant for any of the food categories. There was no association between liking for any of the food categories and adiposity. This suggests that overweight in children is not reflective of differences in liking for selected common foods. Variation in appetitive responsiveness to food with increasing adiposity may be more salient in the development of obesity.     

福州市儿童食物偏好及其影响因素调查研究

[目的]了解儿童的食物偏好状况及其影响因素。[方法]用整群抽样法对福州市区5所幼儿园的778名儿童家长进行儿童食物偏好及其影响因素问卷调查,用SPSS11.5软件包进行数据统计和分析。[结果]在24种食物中,牛奶、零食(冰淇淋、果冻、可乐、炸鸡等)等儿童均很喜欢,而鱼、鸡鸭、青菜、豆腐、胡萝卜、蘑菇和馒头,不喜欢者占25%。男女儿童的食物偏好存在差异。儿童的食物偏好与摄入情况呈正相关(P<0.01);儿童偏好与其母亲食物偏好正相关(P<0.01)。[结论]为保证儿童健康成长,母亲应有合理膳食的知识和有良好的饮食习惯,学校也应开展合理膳食和良好饮食行为的健康教育。     

Temperament and Food Neophobia in Children and their Mothers

We obtained measures of behavioral neophobia, rated neophobia, temperament, and liking for novel and familiar foods for 81 pairs of siblings (ranging in age from 5–11 yearsand their mothers. The children's data revealed a decrease with age in behavioral but not rated neophobia, and there were positive correlations between both measures of neophobia and the temperament dimensions of emotionality, shyness, and negative reactions to foods. In addition, liking for good-tasting novel foods was negatively related to shyness and to negative reactions to foods. For mothers, both measures of neophobia were related to negative reactions to foods and unrelated to any other temperament dimension. The data revealed little evidence of family resemblance (mother-child or sibling-siblingin food neophobia.     

Emotion and food. Do the emotions expressed on other people's faces affect the desire to eat liked and disliked food products?

The aim of the present study was to test if pleasure, neutrality and disgust expressed by other individuals on a photograph could affect the desire to eat liked or disliked food products. Forty-four men and women were presented with two series of photographs. The first series of photographs was composed of six food photographs: three liked and three disliked food products. The second series consisted of the same photographs presented with eaters expressing three different emotions: disgust, pleasure or neutrality. Results showed that the effect of the presence of an eater, and of emotions expressed by this eater, depended on the food category. For the liked foods, the desire to eat was higher when these foods were presented alone than with an eater expressing neutral emotion. When the eater expressed pleasure, the desire to eat these liked foods did not significantly increase. In contrast, when the eater expressed disgust, the desire to eat them significantly decreased. When the foods were disliked, the influence of the pleasant social context was stronger than for the liked foods. The desire to eat the disliked foods actually increased in the presence of an eater expressing pleasure. On the contrary, the disgust and neutral context had no effect on the desire for disliked foods.     

Development of food acceptance patterns in the first years of life

As young omnivores, children make the transition from the exclusive milk diet of infancy to consuming a variety of foods. They must learn to accept a set of the foods available in their environmental niche, and they 'come equipped' with a set of predispositions that facilitate the development of food acceptance patterns, constrained by predisposition and limited by what is offered to them. While children are predisposed to like sweet or salty foods and to avoid sour or bitter foods, their preferences for the majority of foods are shaped by repeated experience. The predispositions that shape food acceptance patterns also include neophobia and the predisposition to learn to prefer and accept new foods when they are offered repeatedly. In addition, the predisposition for associative conditioning affects children's developing food acceptance patterns, resulting in preferences for foods offered in positive contexts, while foods presented in negative contexts will become more disliked via the learning of associations with the social and environmental contexts. Children also learn to prefer energy-dense foods when consumption of those foods is followed by positive post-ingestive consequences, such as those produced when high-energy-density foods are eaten when hungry. Although children are predisposed to be responsive to the energy content of foods in controlling their intake, they are also responsive to parents' control attempts. We have seen that these parental control attempts can refocus the child away from responsiveness to internal cues of hunger and satiety and towards external factors such as the presence of palatable foods. This analysis suggests that taking a closer look at what children are learning about food and eating may provide clues regarding the formation of children's food acceptance patterns, and that this approach also suggests potential causative factors implicated in the aetiology of obesity and the emergence of weight concerns. Current data, although limited, suggest that child-feeding practices play a causal role in the development of individual difference in the controls of food intake, and perhaps in the aetiology of problems of energy balance, especially childhood obesity. These relationships should be pursued in future research.     

Serving larger portions of fruits and vegetables together at dinner promotes intake of both foods among young children

Serving larger portions of energy-dense foods has been shown to promote children's energy intake at meals. Whether larger portions increase children's intake of both fruits and vegetables (F&V) is less clear. A 2×2 within-subjects design systematically varied portion sizes of fruit (75 vs 150 g) and vegetable (75 vs 150 g) side dishes served at dinner. Children's F&V liking was measured using a validated tasting method. Thirty children aged 4 to 6 years were tested in a laboratory setting at 5:00 pm on weekdays from November 2008 through March 2009. Mixed linear models were used to determine effects of fruit portion size, vegetable portion size, and their interaction on food and energy intakes. Data are presented as model-based means±standard error unless otherwise indicated. When portions were doubled, children increased their vegetable intake by 37% (12±4 g; P<0.01) and their fruit intake by 70% (41±6 g; P<0.01). Vegetable portion size effects were not influenced by offering more fruit and vice versa. Portion size effects were limited to children who liked that particular food. Total meal energy intake did not vary by portion size condition. These results indicate that serving larger F&V portions at meals can be used to promote young children's intake of both foods without influencing total meal energy intake. Effects were not seen in children who disliked F&V, suggesting a need to combine increased F&V portions with strategies to increase their acceptance.     

Taste preferences, liking and other factors related to fruit and vegetable intakes among schoolchildren: results from observational studies

The present paper explores the relative importance of liking and taste preferences as correlates of fruit and vegetable (FV) intakes among schoolchildren in Europe. The paper first provides an overview of potential determinants of food choice among children and subsequently summarizes the results of two recent observational studies on determinants of FV intakes among school-aged children. It is proposed that taste preferences and liking are important for children's food choices as part of a broader spectrum of nutrition behaviour determinants. Taste preferences and liking are important for motivation to eat certain foods, but social-cultural and physical environmental factors that determine availability and accessibility of foods, as well as nutrition knowledge and abilities should also be considered. Study 1 shows that children with a positive liking for FV have a greater likelihood to eat fruits (odds ratio (OR) = 1.97) or vegetables (OR = 1.60) every day, while ability and opportunity related factors such as knowledge, self-efficacy, parental influences and accessibility of FV were also associated with likelihood of daily intakes (ORs between 1.16 and 2.75). These results were consistent across different countries in Europe. Study 2 shows that taste preferences were the strongest mediator of gender differences in FV intakes among children; the fact that girls eat more could for a large extend be explained by there stronger taste preferences.     

Effect of television advertisements for foods on food consumption in children

The impact of television (TV) advertisements (commercials) on children's eating behaviour and health is of critical interest. In a preliminary study we examined lean, over weight and obese children's ability to recognise eight food and eight non-food related adverts in a repeated measures design. Their consumption of sweet and savoury, high and low fat snack foods were measured after both sessions. Whilst there was no significant difference in the number of non-food adverts recognised between the lean and obese children, the obese children did recognise significantly more of the food adverts. The ability to recognise the food adverts significantly correlated with the amount of food eaten after exposure to them. The overall snack food intake of the obese and overweight children was significantly higher than the lean children in the control (non-food advert) condition. The consumption of all the food offered increased post food advert with the exception of the low-fat savoury snack. These data demonstrate obese children's heightened alertness to food related cues. Moreover, exposure to such cues induce increased food intake in all children. As suggested the relationship between TV viewing and childhood obesity appears not merely a matter of excessive sedentary activity. Exposure to food adverts promotes consumption.     

Brow and Masticatory Muscle Activity Senses Subjective Hedonic Experiences during Food Consumption

Sensing subjective hedonic or emotional experiences during eating using physiological activity is practically and theoretically important. A recent psychophysiological study has reported that facial electromyography (EMG) measured from the corrugator supercilii muscles was negatively associated with hedonic ratings, including liking, wanting, and valence, during the consumption of solid foods. However, the study protocol prevented participants from natural mastication (crushing of food between the teeth) during physiological data acquisition, which could hide associations between hedonic experiences and masticatory muscle activity during natural eating. We investigated this issue by assessing participants’ subjective ratings (liking, wanting, valence, and arousal) and recording physiological measures, including EMG of the corrugator supercilii, zygomatic major, masseter, and suprahyoid muscles while they consumed gel-type solid foods (water-based gellan gum jellies) of diverse flavors. Ratings of liking, wanting, and valence were negatively correlated with corrugator supercilii EMG and positively correlated with masseter and suprahyoid EMG. These findings imply that subjective hedonic experiences during food consumption can be sensed using EMG signals from the brow and masticatory muscles.     

Behavioral economic analysis of food choice in obese children.

Behavioral economic analysis has shown food choice in normal weight adults is influenced by both liking and constraints on access to food. The present study assessed the contributions of food liking and environmental constraints to choice of moderately liked, low-calorie foods or highly liked high-calorie foods in obese children. Access to the moderately liked food remained on a VR2 schedule, while response requirements for the highly liked food ranged from VR2 to VR32. Subjects chose to work for the higher-rated food at comparisons up to VR2/VR4, showed no preference at VR2/VR8 and their choice shifted to the lower rated food when response requirements for the highly liked food were increased to VR16. These results show that both subjective and environmental factors contribute to children's choice of foods.     

Factor-analytic structure of food preferences in four-year-old children in the UK

Studying the correlative structure of young children's food preferences may help us to understand the influences on the development of eating habits. We investigated patterns of food preferences in 214 same-sex twin pairs aged 4 to 5 years. Mothers completed a questionnaire of their children's likes and dislikes for 94 common foods. The proportion of children having tried each food, and their liking for it, were examined. These two measures were strongly positively correlated (r=0.61). Principal components analysis was used to examine the inter-relationships among preferences for 76 foods that had been tried by at least 75% of the children. Four factors emerged, interpreted from food factor loadings as "Vegetables", "Desserts", "Meat and Fish", and "Fruit", explaining 24% of the variance. Thus, children tended consistently to like or dislike foods within each of these factor categories, independently of patterns of liking in the other factors. Factor loadings were unrelated to average liking for or likelihood of exposure to these foods. The distribution of factor loadings refutes the common assumption that simple sensory properties such as sweetness, saltiness or fattiness predict food preferences. Instead, a preference structure may develop for more complex multimodal sensory syntheses, which could have both biological and learnt bases. Future work comparing the food preference structure of mono- and dizygotic twins should help determine the relative contribution of genetic and environmental influences.     

The relationship of attitudes and experiences of Finnish youths to their hedonic responses to sweetness in soft drinks

Attitudes to sugar and previous experience (liking and use at present and in childhood) of sweet foods as well as hedonic responses to two levels of sweetness in soft drinks were determined in a young adult population (112 males, 112 females). Females were more negative in their attitudes but they reported greater liking of sweet foods. Sugar attitudes were not related to hedonic responses to normal sweetness (9%) in either sex group, but in the case of lower sweetness (5%) negative attitudes increased along with the rated pleasantness, particularly among males. Reported liking and use of soft drinks had some significant correlations with hedonic responses to both sweetness levels, but experiences of other sweet foods were not related to the hedonic responses to sweetness in soft drinks.     

Children’s dietary recalls: the salience of entree and liking for foods on accuracy and order of reporting

This study investigated the impact of entree and liking for foods on the accuracy and order of reporting on children’s school lunch recalls. Data were collected during a series of studies to investigate children’s lunch recalls from a cognitive processing approach to understand better how children remember what they have eaten. Fourth-grade children from four schools were randomly selected, observed eating lunch, and interviewed the same (n = 89) or next (n = 148) day. Foods were classified as matches (observed and reported eaten), omissions (observed but not reported eaten), or phantoms (not observed but reported eaten), and corresponding rates were calculated. Statistical analyses included z tests and permutation tests. For same- and next-day recalls, children were more likely to report entree than other meal components earlier in the interview. For next-day recalls, the phantom rate for the remaining items was lower for children who reported entrees accurately versus inaccurately. For items liked “a lot” compared with items “not liked a lot,” match rates were higher for next-day recalls, and phantom rates were lower for both same- and next-day recalls. Because entree and liking for foods appear to play salient roles in children’s dietary recalls, these results provide guidance regarding the development of specific prompts to increase the accuracy of children’s dietary recalls.     

Disliked food acting as a contaminant during infancy. A disgust based motivation for rejection

This study was conducted to examine whether disliked foods can act as contaminants to liked foods during infancy. Participants (aged 18-26 months, N=18) were offered a liked food that was touching a disliked food, on the same plate. Their response to this liked food was compared to the infants' response to a control condition; a liked food touching a second liked food. The data show that children were less likely to eat a liked food touching a disliked food, than a like-like control. Of the 18 infants tested, eight children either wanted the disliked food completely removed from the plate, or would not consume the liked food at all (N=2) once it was 'contaminated' by the disliked food. This study was the first to test the anecdotal reports that disliked foods can act as contaminants during infancy and the data offer some support for the hypothesis that disgust may influence the acceptance of food during early childhood.