Background and Objectives:
Preventing lifestyle-related diseases is a critical public health issue, contributing not only to individual well-being but also to societal productivity. Weight gain from early adulthood to middle age reflects lifestyle transitions and serves as a predictive marker for metabolic syndrome (MetS).
Previous research suggests that autonomous motivation—engaging in health behaviors for personally endorsed reasons—may be more effective in preventing MetS than controlled motivation, which is driven by external pressures or obligations.
This study aimed to examine the relationships among motivation type, weight gain since age 20, and MetS indicators in a working-age population.
Methods:
A total of 1,411 participants (1,100 men and 311 women; mean age = 46.8 ± 9.7 years) were surveyed. Motivation for healthy eating and physical activity was assessed using constructs from self-determination theory. Weight gain was measured by self-report ("Have you gained more than 10 kg since 20 years old?" Yes/No). MetS-related indicators—including BMI, waist circumference, blood pressure, blood glucose, and lipid profiles—were collected.
Structural equation modeling was conducted with MetS diagnosis as the dependent variable, weight gain as a mediating variable, and motivation type as independent variables.
Results:
Autonomous motivation was negatively associated with both weight gain and MetS diagnosis. In contrast, controlled motivation showed positive associations with weight gain and MetS. Weight gain itself was positively associated with MetS.
Conclusions and Implications:
These findings suggest that fostering autonomous motivation may help mitigate weight gain and reduce the risk of MetS. This highlights the importance of motivational quality in health behavior interventions and supports the integration of self-determination theory into applied psychological practice.