The role of habit strength in the theory of planned behavior for fruit and vegetable intake among women in Saudi Arabia

Low fruit and vegetable (F&V) consumption is prevalent among Saudi women, despite global health recommendations. To identify the psychological determinants of F&V intake using the theory of planned behavior (TPB) and to examine the moderating role of habit. A cross-sectional survey was conducted among 467 adult Saudi women. The questionnaire measured TPB constructs—attitude, subjective norm (SN), perceived behavioral control (PBC), intention, and behavior—alongside habit strength using a validated self-report habit index. Structural equation modeling (SEM) tested the TPB model, and multi-group analysis examined differences across low, medium, and high habit levels. Only 22.3% of women met the WHO recommendation of ≥ 5 F&V servings daily, with significant variation by habit level (10.2% low-habit vs. 30.5% high-habit; p < 0.001). The high habit group showed significantly better knowledge of WHO recommendations (p = 0.013), healthier dietary perceptions (p < 0.001), and more frequent purchasing and preparation of F&V (p < 0.001). Physical activity also increased with habit strength (p < 0.001). Compared to the low-habit group, women in the high-habit group reported higher scores for all the TPB constructs (p < 0.001). SEM results indicated that the TPB model explained 31% of the variance in behavior and 75% in intention. In the overall sample, both intention (β = 0.32, p = 0.005) and PBC (β = 0.26, p = 0.032) predicted F&V intake. PBC was the strongest predictor of intention (β = 0.66, p < 0.001), followed by SN and attitude. Across habit levels, PBC consistently predicted intention; attitude was significant in the low-habit group, and SN in the high-habit group. Perceived control strongly influences both intention and behavior, but habit moderates these relationships. Interventions should enhance self-efficacy and establish regular F&V consumption among Saudi women.