1. Introduction
In recent years, there has been growing interest in nutritional psychology, particularly in understanding how dietary habits influence mental, emotional, and cognitive states. Numerous studies have highlighted the role of one’s diet in shaping their cognitive, behavioural, and physical health, as well as their mental well-being and social relationships [
1,
2,
3]. These effects are deeply intertwined with the social context of food consumption [
4].
Since the development of the Implicit Association Test (IAT) by Greenwald [
5], it has become widely accepted that individual behaviour is guided not only by explicit attitudes but also by implicit attitudes—associations that operate below conscious awareness [
6]. Implicit attitudes, which influence various behaviours, including nutritional choices, have been explored across multiple domains [
7]. According to the Theory of Food (ToF), individuals develop a “food language” during childhood, shaped by the foods they consume and the surrounding social and environmental contexts. This “food language” can have long-lasting effects that persist into adulthood [
8,
9]. Consequently, childhood dietary patterns may influence implicit attitudes toward food later in life.
This study aims to explore aspects of the ToF by examining the relationship between childhood eating habits and implicit food attitudes in adulthood. Specifically, it investigates whether childhood dietary experiences shape implicit attitudes toward certain food groups in adulthood.
- 1.
Novelty and Contribution of this Study
While numerous studies, particularly in Europe, have utilized longitudinal data to explore the relationship between childhood eating behaviours and dietary patterns in adolescence or early adulthood, many have focused on explicit attitudes or long-term behavioural outcomes [
10,
11]. These studies have established a positive association between early-life dietary patterns and later eating habits [
12,
13,
14]. However, this study offers a novel contribution by shifting the focus from explicit to implicit attitudes toward food in adulthood, as measured by the Implicit Association Test (IAT) [
5]. This study’s integration of the Theory of Food (ToF) provides a fresh perspective on how early dietary experiences may create lasting, unconscious associations with food, influencing implicit adult preferences and behaviours [
8,
9]. Furthermore, by examining gender differences in implicit food attitudes, this study adds a unique layer to understanding how childhood eating habits affect adult food choices. Using the IAT to explore these implicit attitudes represents a methodological innovation in this field, offering more profound insights into subconscious influences on food behaviours that may not be captured by explicit measures alone.
- 2.
Theory of Food (ToF)
The ToF posits that eating habits and food choices create cognitive associations, similar to how the Theory of Mind (ToM) addresses the understanding of mental states like beliefs and intentions [
15]. The ToF suggests that early childhood food experiences form cognitive networks that persist into adulthood, influencing future food preferences and behaviours. Just as children learn about the social world through observation and interaction, they develop associations with food that become part of their cognitive framework as adults.
Research has consistently shown connections between one’s food choices, mood, physical health, and mental well-being [
16,
17]. Eating patterns are shaped by visible factors such as the cost and taste of food and hidden influences like culture and branding [
18]. Tools like the IAT help reveal implicit food preferences that are not always consciously acknowledged. For example, IAT results can predict food choices and show how implicit attitudes influence behaviours differently from explicit attitudes [
7]. Additionally, implicit attitudes can steer attention toward taste-related features of food packaging, particularly among those with positive associations toward unhealthy foods [
19]. IATs benefit socially sensitive contexts, where implicit attitudes may impact behaviours more than explicit ones [
5]. Overall, the IAT has proven to be a reliable tool in predicting dietary choices and revealing the influence of implicit attitudes on consumer behaviours [
20,
21].
- 3.
Implicit Attitudes
The study of implicit processes—automatic and unconscious judgments that shape behaviours—began in the mid-20th century [
22]. The human mind categorizes information naturally, leading to implicit attitudes that often go unrecognized but still influence behaviours [
23,
24,
25,
26]. An
attitude is a psychological tendency expressed through an individual’s positive or negative evaluation of a particular object, encompassing emotions like desire, aversion, and preference [
27]. Attitudes are generally categorized into cognitive, emotional, and behavioural components [
6,
28]. While these components are often conscious, social context can cause certain attitudes to remain implicit [
29].
The relationship between implicit and explicit attitudes is complex. While some studies have shown an alignment between the two, particularly in social cognition [
29], others suggest they often diverge [
30]. Despite this, implicit attitudes have been found to predict spontaneous behaviours, such as maintaining social distance in certain situations [
31,
32,
33]. By measuring explicit and implicit attitudes, researchers gain a deeper understanding of behaviours that social or subconscious factors may influence [
34]. IAT tasks are precious in uncovering attitudes that individuals may not be aware of or be willing to report.
- 4.
Gender and Food Choices
Research indicates that gender plays a significant role in food consumption patterns and preferences. Studies have shown that women are generally more likely to adopt healthier eating habits, such as higher fruit and vegetable consumption. At the same time, men may gravitate toward higher-calorie, less-nutritious foods [
35,
36]. Women are often more concerned with the health implications of their food choices, whereas men may prioritize taste and convenience [
37,
38]. Additionally, gender differences in socialization and cultural expectations contribute to variations in food preferences, with women frequently facing societal pressures to conform to ideals of health and appearance [
36,
39]. Understanding the mechanisms behind these gender differences is crucial. Biological factors, such as hormonal influences, may affect one’s appetite and food preferences, while socialization processes shape attitudes and behaviours toward food from an early age. These differences can lead to distinct implicit attitudes toward food that vary by gender, underscoring the importance of considering gender when examining food attitudes and behaviours.
- 5.
The Current Study
This study investigates the relationship between childhood eating habits and implicit food attitudes in adulthood, guided by the Theory of Food (ToF). The ToF suggests that early dietary experiences create lasting cognitive associations with food, influencing future preferences and behaviours. Using the Implicit Association Test (IAT), this study aims to determine whether implicit attitudes toward specific food groups (e.g., snacks and fruits) in adulthood are shaped by childhood eating patterns. The primary hypothesis is that individuals with healthier childhood diets will show more positive implicit attitudes toward healthy foods (e.g., fruits) in adulthood than those with less-healthy childhood diets, which may show a stronger preference for unhealthy foods (e.g., snacks). This study hypothesizes that implicit rather than explicit attitudes will be stronger predictors of adult food preferences and choices. Furthermore, given the observed gender differences in food consumption, this study will also assess whether these implicit attitudes vary by gender. It expects women to demonstrate more positive implicit attitudes toward fruits and healthier eating patterns than men, who may show a stronger implicit preference for high-calorie, less-nutritious foods.
3. Results
A preliminary chi-square analysis of the participants’ demographics was performed, and the results indicate a non-significant association among the variables under investigation. Therefore, the statistical analyses included no demographic variables as covariates (
Table 1).
Table 2 exhibits the means and standard deviations of the childhood consumption of fruits and snacks and the “D score” found in the sample. Also, 104 subjects were found to have a positive D score, that is, to have positive latent attitudes toward fruits and negative ones toward snacks, and 15 subjects were found to have a negative D score, that is, to have positive latent attitudes toward snacks and negative ones toward fruits.
The first research hypothesis proposed a positive relationship between fruit consumption in childhood and the D score, suggesting that participants who ate more fruits as children would have more positive implicit attitudes toward fruits. The second hypothesis suggested a negative relationship between snack consumption in childhood and the D score, indicating that participants who consumed more snacks in childhood would have more positive implicit attitudes toward snacks.
To test these hypotheses, the correlations among the three variables—D score, childhood fruit consumption, and childhood snack consumption—were examined using Pearson’s correlation coefficient (see
Table 3). There was no correlation between childhood fruit consumption and the participants’ D scores. Additionally, there was no correlation between childhood snack consumption and the D scores. Based on these findings, the research hypotheses were not supported.
For further analysis, participants were divided into quartiles based on their fruit consumption during childhood. Differences between the highest and lowest quartiles were examined using an independent sample
t-test (see
Table 4). A statistically significant difference was found between the two groups, with the D scores of participants in the high-fruit-consumption quartile being higher than those in the low-consumption quartile. This indicates that participants who consumed more fruits during childhood held more positive implicit attitudes toward fruits than those with lower fruit consumption.
Additionally, the sample was divided into quartiles based on snack consumption during childhood, and differences between the highest and lowest consumption quartiles were examined using an independent sample
t-test (see
Table 5). No significant difference was found between these two groups.
To understand the differences between the high- and low-fruit-consumption groups in childhood, we examined the differences by gender. Among the women, a statistically significant difference was found between the consumption groups (see
Table 6), with the D score of women with high fruit consumption in childhood being higher than that of women with low fruit consumption. This indicates that women who consumed more fruits during childhood had more positive implicit attitudes toward fruits than those with lower consumption. In contrast, no significant difference was observed among the men between the high- and low-fruit-consumption groups in childhood (see
Table 7).
4. Discussion
The current study investigated the relationship between childhood eating habits and implicit attitudes toward food in adulthood. Contrary to the research hypotheses, no significant relationship was found between childhood fruit consumption and participants’ D scores. Similarly, no association was observed between childhood snack consumption and D scores. This suggests that childhood eating habits may not directly influence implicit attitudes toward food in adulthood. However, additional analyses revealed that participants with high childhood fruit consumption had significantly higher D scores than those with low fruit consumption. This indicates that individuals who ate more fruits as children had more positive implicit attitudes toward fruits than their counterparts. Moreover, a gender-based analysis found similar results among women.
This study focused on a specific aspect of the Theory of Food (ToF) [
8,
9], namely, the relationship between childhood eating habits and implicit attitudes toward food in adulthood. This highlights how the foods consumed during childhood may be linked to the “food theory” individuals develop in adulthood. However, the ToF proposes additional variables that might influence this “food theory,” such as one’s cultural context, family and social experiences related to food, and the emotional context of food consumption [
9]. Therefore, the findings of this study may not necessarily indicate a flaw in the theory but rather suggest that factors beyond childhood eating habits influenced the participants’ implicit attitudes toward food. Overall, this study explored whether childhood eating patterns, specifically, the consumption of fruits and snacks, shape implicit attitudes toward these food groups in adulthood. The results partially support this claim. The finding that higher childhood fruit consumption is associated with more positive implicit attitudes toward fruits, especially among women, suggests that early dietary habits can create lasting cognitive associations, as proposed by the ToF. However, the lack of a significant relationship between snack consumption and implicit attitudes indicates that not all childhood eating patterns may translate into implicit attitudes in adulthood. Thus, the results provide mixed support for the aim of this study. They highlight a gender-specific relationship between healthy childhood eating habits (e.g., fruit consumption) and positive implicit attitudes toward healthy foods in adulthood. This finding, along with the suggestion that the link between early consumption of less-healthy foods (e.g., snacks) and implicit attitudes may be weaker or more complex than was initially hypothesized, has significant implications for public health and nutrition education. This nuanced outcome opens the door for further exploring factors that may mediate or moderate the relationship between childhood eating habits and implicit attitudes toward food, underscoring the importance of continued research in this area.
Indeed, the literature provides evidence of other variables affecting implicit attitudes toward food. For instance, implicit attitudes can be influenced by an individual’s knowledge about the healthiness of foods, where exposure to images of health risks associated with unhealthy foods affects participants’ implicit attitudes toward those foods [
41]. Additionally, values and beliefs also play a role, with vegan participants exhibiting more negative implicit attitudes toward animal-based foods than vegetarians and vegetarians demonstrating more negative attitudes than omnivores. Other factors, such as one’s moral views on food and personality traits like empathy, have also been shown to affect implicit food attitudes [
42].
Furthermore, ongoing dietary restrictions influence implicit attitudes toward food. Individuals on long-term restrictive diets tend to display less -positive implicit attitudes toward tasty foods than control groups [
43]. Additionally, childhood food-related memories, such as being rewarded with food or having a controlled diet, have been linked to the higher consumption of sweet and salty snacks in adulthood. On the other hand, guidance toward healthy eating and restrictions were associated with higher consumption of fruits and vegetables [
44]. Given that implicit attitudes are connected to eating habits and dietary choices [
7], it can be inferred that childhood eating memories influence food consumption habits and implicit attitudes in adulthood.
Another potential explanation for the lack of association between childhood eating habits and implicit attitudes in this study may be related to the validity of the ToF. The findings of this study can be seen as a partial challenge to this theory, suggesting that further research is needed to understand better the complex relationships between childhood dietary habits and various cognitive and emotional variables. When the sample was divided into quartiles reflecting low versus high fruit consumption, differences emerged in D scores, with the high-consumption group displaying higher D scores. This finding suggests a trend toward the research hypothesis, and increasing the sample size in future studies could reveal the anticipated effect in correlation and difference analyses.
To further explore these differences, the sample was analysed by gender. Among the women, those with high childhood fruit consumption had significantly higher D scores than those with low fruit consumption. This difference was not observed among the men. However, it is important to interpret this result cautiously, given the small sample size, particularly in the quartile analysis, where each group contained fewer than 30 participants. This may lead to potential issues with the normality assumption required for statistical tests.
Nonetheless, the more positive implicit attitudes of women in the high-fruit-consumption group could be influenced by additional variables. For example, a study found that women who enjoyed shopping for and preparing food consumed more fruits and vegetables than those who did not enjoy these activities [
45]. This suggests that such behaviours influence women’s implicit attitudes and explain the observed differences.
Previous research has also indicated gender differences in food-related attitudes, with women being reported to consume more fruits, avoid high-fat foods, and limit salty food intake compared to men [
46]. Women tend to place greater importance on the healthiness of foods, while men often prioritize taste [
47]. Additionally, women generally know more about the health effects of their food than men [
48]. These attitude differences are likely reflected at the implicit level, potentially accounting for the gender differences observed in this study. Other research has shown that women’s preferences for healthy food are primarily driven by more excellent nutritional knowledge and a higher motivation to maintain weight than men [
49], further supporting the bias in women’s implicit attitudes toward healthier foods.
An important aspect to consider in understanding childhood eating behaviours and their lasting effects into adulthood is the role of the household’s financial and human capital. Numerous studies have shown that children from affluent households typically have greater access to nutritious foods, face fewer financial barriers, and are more likely to maintain healthier dietary habits into adulthood [
50,
51,
52]. These advantages are often reinforced by parental attitudes toward child-rearing, particularly nutrition. Parents with higher educational backgrounds or human capital tend to prioritize the availability of healthy food options, serve as role models for balanced eating, and engage in positive feeding practices that influence their children’s long-term dietary patterns [
50,
53]. Additionally, children from households of a higher socioeconomic status (SES) often have greater food autonomy and face fewer constraints regarding food choices in adulthood, reinforcing positive food behaviours and shaping their implicit attitudes toward certain foods [
54,
55]. Given that the current study identified a positive relationship between higher childhood fruit consumption and favourable implicit attitudes toward fruits, it is plausible that socioeconomic and familial factors shaped these observed attitudes. Future research should explore how one’s SES, parental attitudes, and access to food during childhood influence their implicit food attitudes in adulthood.
The current study’s findings may also be influenced by limitations related to the tools used. One primary limitation concerns the validity and reliability of the Implicit Association Test (IAT). Some have identified issues with the generalizability and reproducibility of the IAT [
56]. In contrast, others have noted its low test–retest reliability [
57], potentially due to the reliance on reaction times, where even a tenth of a second can significantly affect scores. Additionally, the IAT’s relative nature complicates interpretation, as a strong association between “fruits” and “pleasant” may also reflect a solid opposite association between “snacks” and “unpleasant” [
58]. Another limitation is the reliance on recall questionnaires for childhood eating habits, which may have led to inaccuracies due to the passage of time [
59,
60,
61]. The sample characteristics may also limit the generalizability of the findings, as the average D score was notably higher than that found in previous research [
7], with fewer participants showing negative D scores, suggesting a tendency toward positive implicit attitudes toward fruits and negative attitudes toward snacks.
While this study did not fully validate the ToF, it provides avenues for further research into additional variables that may influence implicit food attitudes. Future studies should explore these factors and employ different methodologies, such as longitudinal studies, to assess childhood dietary habits and their impact on adult implicit attitudes. Psycho-physiological measures (e.g., EEGs, skin conductance, and heart rates) could also be used to evaluate participants’ responses to various foods in adulthood. Additionally, increasing the sample size could help clarify the differences between the high and low-fruit consumption groups by allowing subgroup analyses based on gender and dietary preferences (e.g., vegan or vegetarian).