The relationship between food neophobia and food familiarity, food hedonics and food preferences

Food preferences are an important concept affecting the dietary behaviour of individuals by influencing food choices^{(Reference Marijn Stok, Renner and Allan34)}. ‘Food preference’ means making a choice between food alternatives, with the choice of A rather than B when both are available^{(Reference Chen and Antonelli35)}. Familiarity and hedonics are prominent factors that play important roles in food preferences and are often associated with food neophobia. The concept of ‘food familiarity’ refers to the cognitive ability to apply the knowledge gained through food^{(Reference Aldridge, Dovey and Halford36)}. Food familiarity is not limited only to food tasting experiences. Experience with a food can take several forms. Having visual, contextual or categorical knowledge regarding a food also creates familiarity with that food^{(Reference Aldridge, Dovey and Halford36)}. The other concept of ‘food hedonics’ expresses the sensory evaluation of food characteristics such as taste, texture and appearance. Food hedonics are often described as the degree of liking or pleasantness.

Food liking and preference are closely related but different concepts. Although individuals may like two different foods equally, they may also prefer one over the other; hence, liking and preference are not necessarily synonymous. However, these are sometimes confused with each other. For example, some studies have used the concept of food preference instead of food liking, although they examined food liking^{(Reference Russell and Worsley37–Reference Çınar, Wesseldijk and Karinen40)}. Just as preference is a major but not the only driver for food choice, liking is also a significant but not a sole motive of food preference^{(Reference Marijn Stok, Renner and Allan34)}. In addition, in some studies^{(Reference Skinner, Carruth and Wendy41,Reference Kaar, Shapiro and Fell42)} , the situation of liking and eating a food was questioned together and this concept was called preference.

In food neophobia studies, familiarity was usually assessed using 5-point scales from ‘I do not recognise the product’ to ‘I regularly eat it’ and willingness to try was usually evaluated by the willingness to try a food (‘not at all’ to ‘extremely willing’). Liking/hedonic ratings have usually been assessed with Likert-type scales by asking the degree of liking foods, from ‘dislike extremely’ to ‘like extremely’. Besides, some studies investigated ‘expected liking’, which indicates the liking of foods before tasting them, and ‘actual liking’, which indicates the liking of foods after tasting them. This is important in understanding the relationships between food neophobia, food familiarity, food hedonics and food preferences, as these relationships can influence food choice. Studies investigating the relationships between food neophobia and food familiarity, food hedonics and food preferences in children and adolescents are shown in Table 1, and studies with adults are shown in Table 2.

Table 1. Studies investigating the relationship between food neophobia and food familiarity, food hedonics and food preferences in children and adolescents

FNS, Food Neophobia Scale; CFNS, Child Food Neophobia Scale; FSQ, Food Situations Questionnaire.

* All types of liking ratings including general food liking, expected liking (before tasting) and actual liking (after tasting) were presented.

† FNS score was used as a continuous variable.

‡ FNS scores were divided into three groups according to tertiles.

§ FNS scores were divided into three groups according to quaartiles.

Table 2. Studies investigating the relationship between food neophobia and food familiarity, food hedonics and food preferences in adults and the elderly

FNS, Food Neophobia Scale.

* All types of liking ratings including general food liking, expected liking (before tasting) and actual liking (after tasting) were presented.

† FNS score was used as a continuous variable.

‡ FNS scores were divided according to tertiles.

§ Median score.

|| It is not clear how the cut-off points of FNS score was determined.

¶ Quartiles.

** FNS score was categorised based on the cut-off scores of another study.

†† Mean ± sd.

Familiarity has a notable influence on food preference^{(Reference Aldridge, Dovey and Halford36)}. Children like familiar foods and eat foods they like^{(Reference Cooke43)}; therefore, it is necessary to increase their familiarity with unfamiliar foods in order to incorporate new foods into their diets and provide dietary diversity^{(Reference Aldridge, Dovey and Halford36)}. However, since a negative attitude towards new foods exists in neophobia^{(Reference Stratton, Vella and Sheeshka44–Reference Fenko, Backhaus and van Hoof47)}, food neophobia may be considered a barrier to familiarity. Most studies, except two^{(Reference Raudenbush and Frank48,Reference Laureati, Spinelli and Monteleone49)} , supported this by indicating a negative association between food neophobia and familiarity with many food items^{(Reference Olabi, Najm and Baghdadi45,Reference Loewen and Pliner50–Reference Olabi, Neuhaus and Bustos58)} . Pliner and Hobden^{(Reference Pliner and Karen2)} reported that the negative relationship between food neophobia and familiarity with foods was limited to unfamiliar foods only.

In general, studies have also indicated that food neophobia negatively affects the ‘likelihood of enjoying’ and ‘willingness to try/taste’ familiar foods^{(Reference Jaeger, Rasmussen and Prescott18,Reference Olabi, Najm and Baghdadi45,Reference Loewen and Pliner50,Reference Tuorila, Lähteenmäki and Pohjalainen55,Reference Brown59,Reference Wetherill, Williams and Reese60)} in addition to novel foods and food products^{(Reference Pliner and Karen2,Reference Olabi, Najm and Baghdadi45–Reference Raudenbush and Frank48,Reference Martins, Marcia and Pliner54,Reference Tuorila, Lähteenmäki and Pohjalainen55,Reference Soucier, Doma and Farrell61–Reference Moding and Stifter65)} . The negative relationship between food neophobia and willingness to try the foods offered was stronger for novel foods than for familiar foods^{(Reference Olabi, Najm and Baghdadi45)}. Willingness to try or willingness to cook with specific items such as ethnic foods^{(Reference Olabi, Najm and Baghdadi45,Reference Choe and Cho51,Reference Hwang and Lin52,Reference Mascarello, Pinto and Rizzoli66–Reference Labrecque, Doyon and Bellavance68)} or spices^{(Reference Knaapila, Laaksonen and Virtanen53,Reference Spinelli, De Toffoli and Dinnella69)} was lower among neophobics. Additionally, young adults who favoured spicy and sour foods and had more tolerance for capsaicin were found to be less neophobic^{(Reference Törnwall, Silventoinen and Hiekkalinna70)}. Food neophobia was also negatively associated with the willingness to try/taste new healthy alternative food options such as functional foods^{(Reference Stratton, Vella and Sheeshka44,Reference Labrecque, Doyon and Bellavance68,Reference Howard, Mallan and Byrne71)} . Schickenberg et al.^{(Reference Schickenberg, van Assema and Brug72)} reported that as food neophobia increased, familiarity with different healthy food alternatives and the willingness to taste them decreased.

Food neophobia was negatively associated with liking many food items, particularly strong-tasting^{(Reference Kähkönen, Sandell and Rönkä39,Reference Laureati, Spinelli and Monteleone49)} and unfamiliar/novel foods^{(Reference Fenko, Backhaus and van Hoof47,Reference Raudenbush and Frank48,Reference Jaeger, Chheang and Prescott73,Reference Tuorila, Meiselman and Bell74)} in children and adolescents^{(Reference Mielby, Nørgaard and Edelenbos33,Reference Russell and Worsley37–Reference Kähkönen, Sandell and Rönkä39,Reference Kaar, Shapiro and Fell42,Reference Loewen and Pliner50,Reference Fernandez, DeJesus and Miller75–Reference Sharafi, Duffy and Miller82)} and in adults^{(Reference Costa, Silva and Oliveira5,Reference Jaeger, Rasmussen and Prescott18,Reference Çınar, Wesseldijk and Karinen40,Reference Fenko, Backhaus and van Hoof47–Reference Laureati, Spinelli and Monteleone49,Reference Laaksonen, Knaapila and Niva57,Reference Spinelli, De Toffoli and Dinnella69,Reference Jaeger, Chheang and Prescott73,Reference Siegrist, Hartmann and Keller79,Reference Monteleone, Spinelli and Dinnella83–Reference Januszewska and Viaene85)} . In large-scale research (n 8906) including eight different studies conducted in five countries, food neophobia was inversely associated with the liking of the majority of the 219 considered food and beverage items^{(Reference Jaeger, Chheang and Prescott73)}. In another study^{(Reference Jaeger, Rasmussen and Prescott18)}, food neophobia was negatively associated with even the liking of foods and beverages commonly found in the diet. Individuals with higher levels of food neophobia gave lower actual liking^{(Reference Rodriguez-Tadeo, Patiño-Villena and González Martínez-La Cuesta23,Reference Mielby, Nørgaard and Edelenbos33,Reference Tuorila, Meiselman and Bell74,Reference Fernandez, DeJesus and Miller75)} and pleasantness ratings^{(Reference Mattes86)} to food after taste assessments and accepted foods less often^{(Reference Olabi, Neuhaus and Bustos58,Reference El Dine and Olabi87)} than individuals with lower food neophobia. From a broader perspective, food neophobia was negatively associated with food enjoyment^{(Reference Silva, Jordani and Guimarães88)} and a general liking for the act of eating^{(Reference Costa, Silva and Oliveira5)}.

Among food groups, studies consistently indicate that food neophobia is negatively related to the liking of fruits and/or vegetables in children and adolescents^{(Reference Kähkönen, Sandell and Rönkä39,Reference Kaar, Shapiro and Fell42,Reference Wetherill, Williams and Reese60,Reference Howard, Mallan and Byrne71,Reference Fernandez, DeJesus and Miller75,Reference Appleton, Dinnella and Spinelli77,Reference Coulthard and Sealy78,Reference Kähkönen, Rönkä and Hujo89)} and also in adults^{(Reference Costa, Silva and Oliveira5,Reference Laureati, Spinelli and Monteleone49,Reference De Toffoli, Spinelli and Monteleone56,Reference Laaksonen, Knaapila and Niva57,Reference Siegrist, Hartmann and Keller79,Reference Monteleone, Spinelli and Dinnella83,Reference Agovi, Pierguidi and Dinnella84,Reference Knaapila, Silventoinen and Broms90,Reference Sharafi, Duffy and Miller91)} . Laureati et al.^{(Reference Laureati, Bertoli and Bergamaschi80)} found that food neophobia was inversely correlated with the liking of both vegetables and some fruits among Italian children and reported that children’s liking scores for vegetables significantly decreased with increasing levels of food neophobia, but the liking scores for fruits were stable according to the children’s levels of food neophobia. For this reason, the authors argued that the best indicator of distinguishing food neophobia in children was their liking of vegetables. In line with that view, in a study conducted in Switzerland, increased food neophobia was associated with a decrease in the liking of vegetables, whole-grain bread, crisps, salty nuts and salty snacks, but it was not found to be associated with the liking of fruits among adults^{(Reference Siegrist, Hartmann and Keller79)}. In another study, food neophobia was associated with a higher proportion of vegetables never tried by children, but it was not associated with the proportion of fruits or non-core foods never tried^{(Reference Howard, Mallan and Byrne71)}. Furthermore, the negative correlation between food neophobia and liking of vegetables was found to be stronger than the correlation between food neophobia and liking of fruits^{(Reference Russell and Worsley37)}. One of the possible explanations for this stronger association between food neophobia and liking vegetables compared with liking fruits is that vegetables are not as sweet as fruits and some vegetables have a bitter taste. It has been determined that neophobic individuals avoid intense aromas and pungent, astringent or bitter tastes^{(Reference Laureati, Spinelli and Monteleone49,Reference De Toffoli, Spinelli and Monteleone56,Reference Olabi, Neuhaus and Bustos58,Reference Spinelli, De Toffoli and Dinnella69,Reference Jaeger, Chheang and Prescott73)} . While humans innately prefer sweet tastes, an appreciation of bitter and sour tastes can only be learned by repeated exposure^{(Reference Forestell92)}. However, according to Knaapila et al.^{(Reference Knaapila, Sandell and Vaarno27)}, food neophobics may often refuse to retry foods that they did not like at the first bite, such as vegetables, whereas food neophilics may be willing to try such foods again. Therefore, neophilics may learn to like vegetables more easily than neophobics. Furthermore, most poisonous substances in nature have a bitter taste, so it is argued that natural defence mechanisms in the subconscious reject many vegetables with a bitter taste^{(Reference Dovey, Staples and Gibson93)}.

Few studies have investigated the association between food neophobia and food preferences. Food neophobia was reported to be negatively correlated with healthy preferences in both children^{(Reference Russell and Worsley37)} and adults^{(Reference Sharafi, Duffy and Miller82)}. Adults with higher food neophobia preferred less bitter/astringent food items^{(Reference De Toffoli, Spinelli and Monteleone56)} and preferred fewer dishes with neophobic potential^{(Reference Guzek, Nguyen and Głąbska67,Reference Guzek, Pęska and Głąbska94,Reference Guzek and Głąbska95)} . The food textures preferred by individuals may also differ according to the food neophobia statuses of those individuals. Appiani et al.^{(Reference Appiani, Rabitti and Methven96)} found that food neophobia was negatively associated with preferences for hard foods in children. Another study reported that children who preferred softer and non-particulate versions of foods were more neophobic^{(Reference Cappellotto and Olsen97)}. However, no differences were observed between adults^{(Reference Murray, Easton and Best14)}. The relationship between texture and food refusal may be specific to the childhood period; however, studies on this topic are too limited for a firm conclusion to be drawn.

In summary, studies consistently indicate that food neophobia is negatively correlated with familiarity and the hedonics of many food items and it affects food preferences. These relationships are considerable factors contributing to the association between food neophobia and dietary intake that will be discussed below.

The relationship between food neophobia and motivations for food choices

‘Food choice’ is an umbrella term used to define behaviours and factors that exist before the consumption of food^{(Reference Marijn Stok, Renner and Allan34,Reference Chen and Antonelli35)} . Factors influencing food choice can be grouped into three main categories: food-related features (e.g. sensory features and packaging), individual differences (e.g. knowledge and preference) and society-related features (e.g. culture and policy)^{(Reference Chen and Antonelli35)}. Food neophobia is just one of the individual differences that affect food choices.

Consumers with different levels of food neophobia exhibit different decision-making processes^{(Reference Huang, Bai and Zhang98)}. Several studies have examined the relationship between consumer motivations for food choices and food neophobia. The Food Choice Questionnaire, which includes the nine factors of health, mood, convenience, sensory appeal, natural content, price, weight control, familiarity and ethical concern, has primarily been used in such studies. Jaeger et al.^{(Reference Jaeger, Rasmussen and Prescott18)} conducted a study with adults in New Zealand (n 1167) and found that convenience and familiarity were important factors in food choice, which was positively associated with food neophobia. Later, Jaeger et al.^{(Reference Jaeger, Roigard and Hunter99)} investigated the same relationship based on data obtained from four different studies conducted in three different countries (USA, Australia and New Zealand) and found that as consumers’ levels of food neophobia increased, the importance given to familiarity, convenience and price (the latter only in the Australian population) increased. To replicate these results, an online survey was administered to 5752 adults from the USA, UK and Germany and, in joint analysis, food neophobia was positively associated with the importance given to familiarity, convenience and price, although there were cross-cultural differences^{(Reference Jaeger, Prescott and Worch100)}. Convenience and familiarity were also reported as important factors in different studies^{(Reference Labrecque, Doyon and Bellavance68,Reference Eertmans, Victoir and Vansant101)} . A food-choice experiment study demonstrated that familiarity (neophobic potential) was the major determinant of food choice^{(Reference Guzek, Pęska and Głąbska94)}. These results are not surprising considering the negative relationships between food neophobia and the familiarity and hedonics of unfamiliar foods (see the ‘The relationship between food neophobia and food familiarity, food hedonics and food preferences” section).

Among the other motivations for food choice, the naturalness of food contents and the importance of health aspects of food were generally inversely associated with food neophobia in large-scale cross-sectional studies^{(Reference Jaeger, Roigard and Hunter99,Reference Jaeger, Prescott and Worch100)} . However, food-preference experiment studies did not support this association. In one of these studies, there was no relationship between food neophobia and perceived health^{(Reference Guzek, Pęska and Głąbska94)}, while, in another, health was a more important motivator for neophobics than taste^{(Reference Jezewska-Zychowicz, Plichta and Drywień13)}. This difference in experimental studies can be explained by the difference between food preference and food choice. Food preference is only one of the factors that affect food choice, and food choice is a dynamic process; different factors (such as physical accessibility, price, convenience and food preference) affecting food choice also affect each other in this process. The findings on other motivations are quite contradictory^{(Reference Jaeger, Roigard and Hunter99–Reference Eertmans, Victoir and Vansant101)} and do not reflect dominant factors in terms of food choice related to food neophobia^{(Reference Jaeger, Roigard and Hunter99)}.

Overall, food neophobia affects individuals’ daily food choice decisions. Familiarity and convenience are more prominent motivators in food choices for individuals with high food neophobia, while health and natural contents are less important. These points suggest that food neophobia is a potential barrier to healthy food choices.

The relationship between food neophobia and dietary intake

Dietary intake generally refers to all foods and beverages consumed orally^{(Reference Rutishauser102)}. Dietary intake is assessed through subjective reports and direct observations. Direct observations are not a suitable dietary assessment method for large-scale studies, however, as food consumption is recorded by well-trained research staff. Therefore, in most studies, the dietary intake of individuals is determined using subjective assessments, with open-ended questionnaires, such as 24-h dietary recalls or dietary records, or with closed-ended questionnaires such as FFQ. However, all dietary assessment methods have some limitations, such as social desirability bias and the Hawthorne effect. Additionally, subjective reports have limitations such as recall and interviewer bias^{(Reference Marijn Stok, Renner and Allan34,Reference Shim, Oh and Kim103)} .

Studies exploring the relationship between food neophobia and dietary intake in children and adolescents are given in Table 3. It should be noted that dietary intake was assessed by subjective methods in almost all these studies. Food neophobia has been linked with the consumption of many foods and food groups that are recommended to be consumed daily in our diets. In this respect, the relationship between vegetables and fruits and neophobia has been revealed in many studies. Most of such studies have consistently shown that children or adolescents with higher levels of food neophobia consume fruits and vegetables (FV) less frequently^{(Reference Kozioł-Kozakowska, Piórecka and Schlegel-Zawadzka8,Reference Gan, Tithecott and Neilson15,Reference Xi, Liu and Yang20–Reference Maiz and Balluerka22,Reference Appiani, Rabitti and Methven96,Reference Helland, Bere and Bjørnarå104–Reference Cooke, Wardle and Gibson106)} and in lower amounts^{(Reference Guzek, Głąbska and Mellová7,Reference Gan, Tithecott and Neilson15,Reference Coulthard and Sealy78,Reference Coulthard and Thakker107–Reference Houston-Price, Owen and Kennedy111)} . They also have a lower variety of FV in their diets^{(Reference Perry, Mallan and Koo112)}. Some studies reported this association only for vegetables^{(Reference Guzek, Głąbska and Lange6,Reference Tsuji, Nakamura and Tamai19,Reference Rodriguez-Tadeo, Patiño-Villena and González Martínez-La Cuesta23,Reference Kähkönen, Hujo and Sandell30,Reference Johnson, Davies and Boles31,Reference Galloway, Lee and Birch113,Reference de Wild, Jager and Olsen114)} . Only one study conducted with Brazilian adolescents found no association between food neophobia and FV consumption^{(Reference de Andrade Previato and Behrens24)}. The insufficient intake of FV in the entire study group and the low food neophobia scores of the group may be linked with that lack of association. There is also a negative association between food neophobia and consumption of animal protein sources, especially meat and its derivatives. Generally, the consumption of red meat^{(Reference Xi, Liu and Yang20)}, eggs^{(Reference Kozioł-Kozakowska, Piórecka and Schlegel-Zawadzka8)}, chicken^{(Reference Xi, Liu and Yang20,Reference Cooke, Carnell and Wardle108)} and fish^{(Reference Xi, Liu and Yang20,Reference Maiz and Balluerka22,Reference Helland, Bere and Bjørnarå104)} was negatively associated with food neophobia, although there are also reports that indicate no association for eggs^{(Reference Xi, Liu and Yang20)}, meat^{(Reference Helland, Bere and Bjørnarå104)} and fish^{(Reference Rodriguez-Tadeo, Patiño-Villena and González Martínez-La Cuesta23)}.

Table 3. Studies investigating the relationship between food neophobia and dietary intake in children and adolescents

FNS, Food Neophobia Scale; CFNS, Child Food Neophobia Scale; FSQ, Food Situations Questionnaire.

* FNS score was used as a continuous variable.

† FNS scores were divided according to tertiles.

‡ It is not clear how the cut-off points of FNS score was determined.

§ Quartiles.

|| Mean ± sd.

The relationship between food neophobia and less frequent consumption of FV and meats has also been supported from a different perspective. Positive correlations were found between food neophobia and plant neophobia and meat neophobia^{(Reference Çınar, Karinen and Tybur115)}. One of the explanations for the association between food neophobia and less frequent consumption of FV and animal products may be sensory sensitivity. How neophobics interpret visual cues and their disgust sensitivity may be factors involved in the consumption of these foods. Even visual cues from foods that do not ‘look right’ may lead to the rejection of foods. Moreover, other sensory properties of foods including bitter tastes, strong odours and hard textures may also contribute to food refusal. Another explanation is that these foods may be perceived as potentially poisonous plants or animals, which was a life-saving attitude in hunter-gatherer days. Another reason for the lower acceptance and consumption of these foods, especially vegetables, may be related to the fact that these foods do not have innately liked sensory properties, such as sweet and salty tastes and fatty mouthfeel. Furthermore, individuals’ pathogen-related disgust sensitivity and germ-aversion behaviours may play roles in meat neophobia since meats have higher microbial loads and deteriorate faster than other foods. The association of meat consumption with masculinity and empathy with animals may also be potential explanations for neophobic behaviours towards meat. Despite all these hypotheses, however, it is not exactly clear why children refuse these foods. Further studies conducted with qualitative research methods may provide a better understanding of the drivers of FV and meat rejection among neophobics.

The results on milk and dairy products^{(Reference Gan, Tithecott and Neilson15,Reference Xi, Liu and Yang20,Reference Dos Anjos, Dos Santos Vieira and Freire Siqueira25,Reference Maiz, Urkia and Bereciartu81,Reference Cooke, Carnell and Wardle108)} , grains^{(Reference Gan, Tithecott and Neilson15,Reference Proserpio, Almli and Sandvik21,Reference Maiz and Balluerka22,Reference Cooke, Carnell and Wardle108)} and sweets/snacks are inconsistent^{(Reference Kozioł-Kozakowska, Piórecka and Schlegel-Zawadzka8,Reference Gan, Tithecott and Neilson15,Reference Xi, Liu and Yang20–Reference de Andrade Previato and Behrens24,Reference Appiani, Rabitti and Methven96,Reference Helland, Bere and Bjørnarå104,Reference Cooke, Carnell and Wardle108)} . Population-based differences in dietary habits, the variety among methods for assessing dietary consumption and the discrepancies in the definitions of food groups such as ‘snacks’ may be partly responsible for these different results.

Studies investigating food neophobia and dietary diversity have consistently found that children with higher levels of food neophobia have lower dietary diversity^{(Reference Xi, Liu and Yang20,Reference Falciglia, Couch and Gribble28,Reference Johnson, Davies and Boles31,Reference Gomes, Barros and Pereira38,Reference Quick, Lipsky and Laffel116,Reference El Mouallem, Malaeb and Akel117)} . However, there are few studies investigating the dietary variety of adolescents^{(Reference Quick, Lipsky and Laffel116,Reference Roßbach, Foterek and Schmidt118)} . One of them was conducted with German adolescents and neither overall nor core food dietary variety differed according to the neophobia status of the participants. Only a trend towards limited core food variety was detected among boys with higher levels of food neophobia^{(Reference Roßbach, Foterek and Schmidt118)}. Another study conducted with type 1 diabetics reported a negative association between food neophobia and dietary variety^{(Reference Quick, Lipsky and Laffel116)}. The less frequent intake of core food groups among neophobic individuals probably leads to reduced dietary diversity.

Although some studies^{(Reference Falciglia, Couch and Gribble28,Reference Maslin, Grimshaw and Oliver119)} have not found an association between food neophobia and nutrient intake, most studies have shown that energy intake and macro- and micronutrients differ significantly according to levels of food neophobia. Findings on the relationship between food neophobia and energy intake are contradictory^{(Reference Kozioł-Kozakowska, Piórecka and Schlegel-Zawadzka8,Reference Gan, Tithecott and Neilson15,Reference Falciglia, Couch and Gribble28,Reference Cooke, Carnell and Wardle108)} . Food neophobia was associated with lower protein intake^{(Reference Gan, Tithecott and Neilson15,Reference Roßbach, Foterek and Schmidt118)} and the percentage of total energy intake from protein^{(Reference Kutbi, Asiri and Alghamdi26)}. The carbohydrate intake of neophobic preschool children was found to be significantly higher compared with neophilics^{(Reference Kozioł-Kozakowska, Piórecka and Schlegel-Zawadzka8)}. The findings related to micronutrient intake have been slightly more consistent, showing that children with higher food neophobia had lower intake of many micronutrients^{(Reference Kozioł-Kozakowska, Piórecka and Schlegel-Zawadzka8,Reference Wetherill, Williams and Reese60,Reference Cooke, Carnell and Wardle108,Reference Chitra, Adhikari and Radhika120)} . Kozio-Kozakowska et al.^{(Reference Kozioł-Kozakowska, Piórecka and Schlegel-Zawadzka8)} indicated that neophobic children had significantly lower thiamine intake than neophilics, and there was a negative correlation between the level of food neophobia and vitamin C intake. Food-neophobic preschool children met 84 % of the recommended thiamine intake, 47·5 % of the recommended folate intake and only 36 % of the recommended vitamin C intake because they rarely ate vegetables. For neophilic children, these values were found to be approximately 99, 53 and 68 %, respectively. Kutbi et al.^{(Reference Kutbi, Asiri and Alghamdi26)} found a lower intake of various minerals, including K, P, Mg, Fe, Zn, and Se, among neophobic children aged 6–12 years. Gan et al.^{(Reference Gan, Tithecott and Neilson15)} reported similar results among children aged 7–10 years. Overall, it may be argued that protein intake, vitamin intake and mineral intake are all sensitive to food neophobia. However, the results regarding energy intake are contradictory and need further verification. Since studies on the adolescence period are limited, more studies are needed to interpret the relationship between food neophobia and macro- and micronutrient intake.

When all these relationships between food neophobia and food and nutrient intake are evaluated, it is not surprising that food neophobia is negatively associated with the quality of diet. As can be seen in Table 3, studies have reported that children and adolescents with higher levels of food neophobia have poorer diet quality^{(Reference Maiz and Balluerka22,Reference Rodriguez-Tadeo, Patiño-Villena and González Martínez-La Cuesta23,Reference Falciglia, Couch and Gribble28,Reference Quick, Lipsky and Laffel116,Reference Bell, Jansen and Mallan121,Reference Jarman, Ogden and Inskip122)} . Rodriguez-Tadeo et al.^{(Reference Rodriguez-Tadeo, Patiño-Villena and González Martínez-La Cuesta23)} and Maiz and Balluerka^{(Reference Maiz and Balluerka22)} determined that there was an inverse linear relationship between the degree of food neophobia and adherence to the Mediterranean diet. There was a negative correlation between food neophobia and the Healthy Eating Index score^{(Reference Quick, Lipsky and Laffel116)}, and the Healthy Eating Index scores of neophobic children were significantly lower than the average and those obtained for neophilic children^{(Reference Falciglia, Couch and Gribble28)}. Bell et al.^{(Reference Bell, Jansen and Mallan121)} also calculated dietary risk scores using portion sizes and frequencies of foods and found that higher food neophobia scores were associated with a higher risk for poor diet quality. The relationship between vegetarianism and food neophobia was examined in a single study conducted with adolescent girls and vegetarians were found to be more neophobic than non-vegetarians^{(Reference Chitra, Adhikari and Radhika120)}. Overall, the results indicate that children with a higher level of food neophobia need more support to eat core food groups and improve the quality of their diets.

Food neophobia has negatively associated with the dietary intake of adults as well (Table 4). Jaeger et al.^{(Reference Jaeger, Rasmussen and Prescott18)} reported that food neophobia was negatively related to the consumption frequency of familiar foods in the daily diet as well as unfamiliar foods. Food neophobia has also been linked to the less frequent consumption of core foods such as FV^{(Reference Costa, Silva and Oliveira5,Reference Knaapila, Sandell and Vaarno27,Reference Laaksonen, Knaapila and Niva57,Reference Siegrist, Hartmann and Keller79,Reference Knaapila, Silventoinen and Broms90,Reference Predieri, Sinesio and Monteleone123–Reference Paupério, Severo and Lopes125)} or fish^{(Reference Siegrist, Hartmann and Keller79,Reference Knaapila, Silventoinen and Broms90,Reference Predieri, Sinesio and Monteleone123)} . Only one study reported contrary results, concluding that there were more people among food neophobics who often consumed fresh FV^{(Reference Jezewska-Zychowicz, Plichta and Drywień13)}. The findings on the relationships between food neophobia and the consumption of red meat^{(Reference Jezewska-Zychowicz, Plichta and Drywień13,Reference Siegrist, Hartmann and Keller79,Reference Jaeger, Prescott and Worch100)} and milk and dairy products^{(Reference Costa, Silva and Oliveira5,Reference Jezewska-Zychowicz, Plichta and Drywień13,Reference Predieri, Sinesio and Monteleone123,Reference Zickgraf and Schepps126)} have been contradictory. On the other hand, except for the study of Knaapila et al.^{(Reference Knaapila, Silventoinen and Broms90)}, most studies have reported food neophobia to be positively associated with the consumption of tasty but unhealthy foods and drinks^{(Reference Jaeger, Rasmussen and Prescott18,Reference Jaeger, Prescott and Worch100,Reference Predieri, Sinesio and Monteleone123,Reference Zickgraf and Schepps126)} . Considering these food consumption habits, the results of studies reporting that food neophobia was positively related to the percentage of energy from free sugars^{(Reference Hazley, McCarthy and Stack124)} or that individuals with higher food neophobia scores had higher percentages of total energy intake from carbohydrates and saturated fat^{(Reference Sarin, Taba and Fischer9)} are not surprising.

Table 4. Studies investigating the relationship between food neophobia and dietary intake in adults and the elderly

* FNS score was used as a continuous variable.

† FNS scores were divided according to tertiles.

‡ Quartiles.

§ FNS score was categorised based on the cut-off scores of another study.

|| Mean ± sd.

Table 5. Descriptions of intervention studies aiming to reduce food neophobia

* FNS score was used as a continuous variable.

† It is not clear how the cut-off points of FNS score were determined.

‡ FNS scores were divided according to quartiles.

Among population-based studies, Sarin et al.^{(Reference Sarin, Taba and Fischer9)} found that food neophobia was associated with lower diet quality as determined using the Baltic Sea Diet Score. A similar finding was reported in another study conducted with Finnish adults^{(Reference Knaapila, Sandell and Vaarno27)}. Hazley et al.^{(Reference Hazley, McCarthy and Stack124)} found that food neophobia was inversely associated with dietary variety but not with diet quality among Irish adults. Predieri et al.^{(Reference Predieri, Sinesio and Monteleone123)} revealed that food neophobia was negatively related to compliance with the Mediterranean diet. However, in a non-population-based study^{(Reference Aiello, Peluso and Villaño Valencia127)}, no significant relationship was found between food neophobia and adherence to a Mediterranean diet.

Although further studies conducted with different populations will provide a better understanding of the relationship between food neophobia and dietary intake among adults, the trends observed among children and adolescents indicate that dietary habits learned or acquired during childhood persist into adulthood. Consequently, it can be suggested that food neophobia is related to poor dietary behaviour throughout the lifespan and that the possible effects of food neophobia on diet are carried from early life into later life.

The relationship between food neophobia and eating behaviours

Food neophobia is often discussed together with picky eating. Picky eating is defined as the rejection of a substantial number of foods that may be familiar or unfamiliar. The concepts of food neophobia and picky eating are sometimes confused with each other. While there is a tendency to be selective about food in both cases, neophobia is characterised by the reluctance to eat new foods. However, for picky eaters, familiarity is not the issue. They may reject both familiar and unfamiliar foods. Picky eaters may also reject certain types of food textures, or they may consume inadequate amounts of food. Contrary to neophobics, who usually reject food before tasting it due to the underlying fear of novelty, picky eaters generally reject food after tasting. Although the discussion of whether these two phenomena share a common etiological pathway is still ongoing^{(Reference Lafraire, Rioux and Giboreau128)}, all studies support the conclusion that these two forms of food rejection are highly correlated with each other^{(Reference Xi, Liu and Yang20,Reference Silva, Jordani and Guimarães88,Reference Galloway, Lee and Birch113,Reference Quick, Lipsky and Laffel116,Reference Elkins and Zickgraf129,Reference Zickgraf, Franklin and Rozin130)} .

Apart from picky eating, food neophobia was positively associated with satiety responsiveness and emotional undereating among children^{(Reference Silva, Jordani and Guimarães88)}. In healthy young Swedish adults, it was negatively correlated with appetite^{(Reference Nordin, Broman and Garvill131)}. These findings are logical, as food neophobia is generally positively correlated with a lack of interest in food^{(Reference Silva, Jordani and Guimarães88)}.

Eating occasions were also evaluated in some studies. Children who rarely ate at the dinner table with their families, often ate in their rooms and ate while playing games (tablet, PlayStation, etc.) were found to have higher levels of food neophobia compared with other children^{(Reference El Mouallem, Malaeb and Akel117)}. It has usually been indicated that there is a negative correlation between food neophobia and healthy eating habits^{(Reference Kozioł-Kozakowska, Piórecka and Schlegel-Zawadzka8,Reference Maiz and Balluerka22)} . Preschool children with high levels of food neophobia were found to consume fewer meals and more snacks between meals^{(Reference Kozioł-Kozakowska, Piórecka and Schlegel-Zawadzka8)}, and neophobic adolescents skipped breakfast more often^{(Reference Maiz and Balluerka22)}.

Some studies^{(Reference Jaeger, Prescott and Worch100,Reference Chitra, Adhikari and Radhika120)} have shown that food neophobia is negatively associated with the consumption frequency of take-away foods and eating meals outside the home. That may be related to the fact that neophobic individuals avoid meals outside the home due to anxiety about new foods. The acceptance of school lunches was also negatively associated with food neophobia^{(Reference Tuorila, Palmujoki and Kytö132)}. However, currently there is limited evidence regarding eating occasions and these findings need to be verified. Age, sex and cultural differences may also have interactions with the relationship between food neophobia and eating behaviour, which needs to be addressed in further studies.