Association of dieting self-efficacy, weight management nutrition knowledge, physical activity, and dietary pattern among Turkish adults: a cross-sectional study

Unhealthy diets and obesity are major contributors to noncommunicable diseases worldwide. Dieting self-efficacy and nutrition knowledge are believed to influence eating behavior; however, their combined effect on dietary pattern is not well understood. This study aimed to examine the relationship between dieting self-efficacy, weight management-related nutrition knowledge, and dietary pattern among adults. This cross-sectional study recruited 1457 adults (aged 19–64) from Erzurum, Türkiye. Participants completed validated measures assessing dieting self-efficacy (DIET-SE), weight management nutrition knowledge (WMNKQ), and dietary intake using a brief food frequency questionnaire. A dietary pattern score was derived using principal component analysis (PCA). Physical activity was assessed using the International Physical Activity Questionnaire–Short Form (IPAQ-SF). Partial Spearman correlations (adjusting for age and sex), multiple linear regressions, and path analysis were conducted to examine associations and mediation effects. The sample had a median age of 24 years, and 10.2% were obese. DIET-SE and WMNKQ scales showed high internal reliability (Cronbach's α ≥ 0.72). Nutrition knowledge was positively correlated with self-efficacy (ρ = 0.12, p < 0.01); however, both were inversely associated with dietary pattern (ρ = -0.22 and − 0.15, respectively; p < 0.01). Regression analyses confirmed that higher DIET-SE and WMNKQ scores independently predicted poorer dietary pattern (β = -0.21 and − 0.13; p < 0.001). Female sex, higher education, and income were positively associated with WMNKQ scores, while age negatively predicted dietary pattern. Path analysis supported a partial mediation model: WMNKQ positively predicted DIET-SE (β = 0.13), which was negatively associated with dietary pattern (β = -0.20). The results demonstrated that participants with higher weight-management knowledge and dieting self-efficacy had lower overall dietary pattern. These findings highlight that knowledge alone is not enough to ensure healthy eating, and that self-efficacy must be properly directed.