1. Introduction
Global trade liberalization, economic growth, and rapid urbanization have profoundly transformed people’s living environments, dietary habits, and lifestyles [
1]. The increasing consumption of processed and convenience foods, coupled with the rise in dining out—particularly at fast-food establishments—has become a hallmark of modern life [
2,
3]. However, eating outside the home often limits individuals’ ability to control or understand the nutritional content and quality of their meals [
4]. Compared to home-cooked foods, meals consumed away from home are more likely to be high in calories and fat, contributing to unhealthy dietary patterns that pose a significant global public health challenge [
5,
6,
7].
In China, the world’s most populous country, obesity has become a pressing concern. According to a 2023 national survey conducted by the PLA General Hospital, 34.8% of Chinese adults were classified as overweight and 14.1% as obese [
8]. The health implications of overweight and obesity are wide-ranging, increasing the risk of chronic conditions such as hypertension, type 2 diabetes, and cardiovascular disease [
5,
6,
7]. Additionally, individuals living with obesity often face weight-based stigma and discrimination, which can adversely affect both mental and physical health [
9]. This stigma may lead to physiological imbalances, including elevated cortisol and inflammatory markers [
10,
11], as well as symptoms of depression and anxiety [
12,
13].
Given the complexity of obesity and its multifaceted consequences, there is an urgent need for comprehensive and multi-level public health strategies. While many interventions have focused on improving the food environment, enhancing access to nutritious options, and promoting physical activity [
14], emerging evidence highlights the critical role of behavioral motivation—particularly intrinsic motivation—in maintaining healthy behaviors over time [
15,
16].
Intrinsic motivation refers to engaging in behaviors for inherent enjoyment, interest, or personal satisfaction. Recent research further suggests that it may also arise from perceiving health-related behaviors as meaningful steps toward personal goals, thereby enhancing persistence and psychological commitment [
17]. In the context of healthy eating, intrinsic motivation may be shaped by experiences such as enjoyment of food, autonomy in food choices, and a sense of accomplishment in maintaining a nutritious diet.
Cultivating such motivation is increasingly recognized as key to effective and sustainable obesity prevention strategies [
18,
19]. Without a deeper understanding of consumers’ motivational drivers, public health interventions may fall short of producing meaningful behavioral change [
20]. Notably, recent national efforts in China have begun to incorporate motivation-focused approaches. The China Adult Obesity and Nutrition Guidelines (2024) [
21], for instance, promote culturally sensitive meal plans, such as low-fat adaptations of Sichuan cuisine or warming northern dishes, to preserve culinary satisfaction while improving diet quality [
21]. In addition, the 2024 launch of the Resident Electronic Health Records system by the National Health Commission enables individuals to monitor real-time changes in health metrics, thereby reinforcing self-efficacy and a sense of progress in lifestyle changes [
22].
Despite these advances, few studies have empirically examined how intrinsic motivation interacts with established psychological constructs to shape healthy eating intentions among Chinese adults. The theory of planned behavior (TPB) has been widely used to predict health-related behaviors through three key constructs: attitudes, subjective norms, and perceived behavioral control (PBC). However, individuals may hold positive attitudes toward a behavior or experience social pressure to engage in it without necessarily acting unless they are also motivated by personal relevance or expected outcomes [
23]. Therefore, integrating motivation into the TPB framework may provide a more comprehensive understanding of how healthy eating intentions are formed.
While most previous research has focused on specific cities in northern or southern China, large-scale national data reveal regional disparities in the prevalence of overweight and obesity—generally higher in northern regions and among men [
8]. This study addresses these gaps by incorporating regional differences and exploring the role of intrinsic motivation as a mediator within an extended TPB model. This study aims to: first, validate a measurement model using confirmatory factor analysis (CFA) to ensure the structural reliability and internal consistency of TPB constructs and motivation among Chinese adult; second, extend the TPB framework by incorporating intrinsic motivation and examining its mediating role in the relationships between attitudes, subjective norms, and behavioral intention; and, last, develop and test an integrated structural equation model (SEM) to explore how motivation contributes to healthy eating intentions and to inform the design of more effective, motivation-oriented public health interventions.
4. Discussion
This study employed an online survey conducted between 2019 and 2023 to examine the relationships among attitudes, subjective norms, PBC, motivation, and healthy eating intentions among adults residing in five Chinese cities: Shanghai, Beijing, Anhui, Henan, and Daqing. SEM revealed significant associations between both attitude and subjective norms with motivation. Furthermore, motivation and PBC were significantly associated with behavioral intention. Specifically, motivation (SE = 0.014, critical ratio = 5.625, p < 0.001) and PBC (SE = 0.020, critical ratio = 47.167, p = 0.012) both showed strong predictive value. Motivation also mediated the effects of attitude (standardized indirect effect = 0.011, SE = 0.004, p = 0.004; 95% CI: 0.004–0.021) and subjective norms (standardized indirect effect = 0.022, SE = 0.006, p < 0.001; 95% CI: 0.013–0.035) on behavioral intention. These findings highlight the central role of motivation in the pathway from social–cognitive factors to behavioral intention. Individuals who perceive healthy eating as important and experience social support are more likely to be intrinsically motivated and, subsequently, more likely to form strong intentions to adopt healthy eating behaviors. Thus, motivation acts as a psychological bridge linking external influences and internal decision making.
Our findings are consistent with previous studies conducted in Beijing [
24], Daqing [
26], and Anhui and Shanghai [
25], which identified PBC as the strongest determinant of healthy eating intentions. The current results further confirm that individuals with greater perceived behavioral control—those who anticipate fewer obstacles and perceive more resources—are more likely to form and act upon intentions to eat healthily [
44]. Therefore, improving structural support and enhancing individuals’ perceived ease of engaging in healthy eating may increase actual behavior change. A significant positive association was also found between motivation and healthy eating intention, aligning with previous research that identifies motivation as a key determinant of behavior [
45,
46]. Recent perspectives emphasize that motivation extends beyond pleasure or enjoyment, also encompassing goal-directed processes. When healthy eating is perceived as a means to achieve valued outcomes, such as improved physical health, reduced disease risk, or family well-being, it is more likely to elicit sustained behavioral commitment [
17]. In this sense, intrinsic motivation is not merely a subjective preference but an internalized force shaped by personal relevance and perceived health risk, particularly salient in a population where nearly half of adults are overweight or obese [
8]. Therefore, enhancing awareness of the long-term benefits of healthy eating may further stimulate goal-aligned motivation and foster durable behavioral change.
Our findings regarding attitude are in line with studies among Dutch families and Australian undergraduates [
47,
48], suggesting that positive attitudes toward healthy eating enhance motivation and, subsequently, behavioral intention. As attitude reflects personal evaluation of the behavior [
23], cultivating positive perceptions of healthy eating should remain a central focus of public health campaigns. In contrast, results concerning subjective norms showed some variability across studies. In our sample, subjective norms significantly influenced motivation and intention via motivational mediation. However, prior research in medium-sized Dutch cities found no significant relationship [
47], while studies in Australian samples confirmed such effects [
48]. Subjective norms, often shaped by perceived social pressure and the desire to meet others’ expectations [
47], may vary in impact depending on sociocultural context. In China, a collectivist society with strong cultural emphasis on social harmony and conformity, individuals may be particularly influenced by normative expectations. As emphasized by President Xi Jinping, “The unity of thought, will, and action is the fundamental reason for China’s continued strength” [
49]. This cultural backdrop may help explain the stronger role of subjective norms in our Chinese sample, though direct cross-cultural comparisons must be approached cautiously due to methodological differences.
Consistent findings across several studies have shown that, even after controlling for covariates in the TPB model, PBC continues to exert a significant influence on eating behavioral intention, whereas the effects of attitude and subjective norms are often inconsistent [
24,
25,
26,
50,
51]. These stable patterns suggest that regional differences may not play a major role in shaping intention. Instead, cultural factors, such as collectivist versus individualist values, may be more relevant in explaining variations in health behavior formation. Future research should, therefore, prioritize cultural dimensions over geographic distinctions when refining TPB-based models. Building on this understanding, the following practical implications are suggested. Since PBC has played a significant role in enhancing the dependent variable, eating behavioral intention, strategies for increasing PBC may be beneficial. Sharing successful cases of individuals who have maintained a healthy diet could trigger dietary intentions. These forms of sharing not only enhance PBC but also have the added advantage of increasing subjective norms, the second most significant predictor in this study. By sharing successful examples, individuals who are exposed to these cases may, in turn, share them with others in their social circles, creating a snowball effect. This ripple strategy can be considered an effective practical approach to promoting a healthy diet across broader populations.
While these practical strategies hold promise, several limitations should be noted. First, motivation could be classified into autonomous and controlled motivation [
52]. However, we only included autonomous motivation in our study. Therefore, further studies are needed to explore motivation intensively and how different motivation affects behavioral intention in distinct ways, particularly in cross-cultural settings where motivational patterns may diverge. Second, due to the nature of a cross-sectional study, our study cannot establish causality; future longitudinal studies are needed to confirm causal relationships. Third, within the TPB framework, future studies should employ covariate-adjusted models controlling for potential confounding factors to explore both the mediation effects and potential effect modification of motivation on behavioral intention. Despite these limitations, this study offers several strengths. Unlike prior studies limited to single-city data [
24,
25,
26], this research draws on data from five diverse regions, offering a more comprehensive picture of healthy eating intentions among Chinese adults. Additionally, this study employed SEM, a sophisticated analytical technique that allows for simultaneous testing of multiple pathways, providing a more robust understanding than traditional regression approaches. Importantly, this study is among the first to incorporate motivation as a mediating variable within the TPB framework, elucidating the psychological mechanisms through which attitudes and subjective norms shape behavioral intention.
Future research may explore several directions. First, validation of this extended TPB model across larger and more diverse populations is needed, particularly to examine potential heterogeneity by socioeconomic status, age, or health condition. Second, future studies should consider disaggregating motivation into autonomous, controlled, and motivational subtypes to explore their differential effects on intention and behavior. Third, longitudinal designs could track how changes in motivation relate to the maintenance of healthy eating over time, providing insight into sustained behavior change. Such findings would inform the development of tailored, motivation-centered nutrition interventions that leverage digital tools, social incentives, and supportive environments. Bridging theoretical insight and practical application will be essential to improving population-level dietary behaviors and advancing chronic disease prevention in China.
5. Conclusions
This study investigated the role of motivation in shaping healthy eating intentions within an extended TPB framework. Amid China’s rapid economic growth and urbanization, the rising prevalence of obesity has emerged as a critical public health concern, increasing the risk of chronic diseases such as hypertension, type 2 diabetes, and cardiovascular conditions and negatively impacting both physical and mental health. Promoting healthy dietary behaviors is, thus, essential to mitigating these risks. An online survey conducted between 2019 and 2023 collected data from 2114 adults across several regions in China. SEM showed that attitudes and subjective norms were significantly associated with motivation, while motivation and PBC strongly predicted healthy eating intentions. Motivation also mediated the effects of attitudes and subjective norms on intention, highlighting its key intermediary role. The SEM results revealed that attitudes and subjective norms were significantly associated with motivation, while both motivation and PBC strongly predicted healthy eating intentions. Moreover, motivation mediated the effects of attitudes and subjective norms on behavioral intention, as confirmed by statistically significant indirect effects. These findings suggest that attitudes and social expectations alone are insufficient to explain intention formation; motivation is a crucial intermediary that bridges external influences and internal commitment. Importantly, intrinsic motivation appears to stem not only from identification with healthy eating behaviors themselves but also from their perceived utility in achieving personally meaningful goals. When individuals recognize that healthy eating contributes to improved health or quality of life, they are more likely to sustain behavioral intention and engagement. This insight broadens the explanatory scope of TPB and offers theoretical grounding for the design of more targeted and motivation-enhancing interventions. In the context of complex food environments and accelerated lifestyles, fostering motivation for healthy eating should be a central focus of future intervention strategies. Policymakers are encouraged to apply behavioral science tools, such as personalized health feedback, social incentive structures, and digital health platforms, to promote the adoption and maintenance of healthy eating practices. Tailored strategies that address the diverse needs of different socioeconomic groups are also essential to reducing health disparities. By combining motivation-centered interventions with long-term public health initiatives, it is possible to create a supportive social environment for healthy eating, reduce the burden of obesity and chronic diseases, and improve overall population health.