International Journal of Behavioral Medicine

, Volume 25, Issue 2, pp 265–270 | Cite as

Effects of Self-Efficacy on Healthy Eating Depends on Normative Support: a Prospective Study of Long-Haul Truck Drivers

  • Kyra Hamilton
  • Martin S. Hagger



Fruit and vegetable intake (FV) is insufficient in industrialized nations and there is excess of discretionary food choices (DC; foods high in fat, sugar, and salt). Long-haul truck drivers are considered a particularly at-risk group given the limited food choices and normatively reinforced eating habits at truck rest-stops. Self-efficacy and normative support are key determinants of eating behavior yet the processes underlying their effects on behavior are not well understood. We tested the direct and interactive effects of self-efficacy and normative support on healthy eating behaviors in long-haul truck drivers in a prospective correlational study.


Long-haul truck drivers (N = 82) completed an initial survey containing self-report measures of behavioral intentions, perceived normative support, and self-efficacy for their FV and DC behaviors. Participants completed a follow-up survey 1 week later in which they self-reported their FV and DC behavior.


A mediated moderation analysis identified an interactive effect of self-efficacy and normative support on behavior mediated by intention for FV and DC behavior. Specifically, we confirmed a compensation effect in which self-efficacy was more likely to have an effect on FV and DC behavior through intentions in participants with low normative support.


Results indicate the importance of self-efficacy in predicting FV and DC intentions and behavior in the absence of a supportive normative environment. The compensatory effect of self-efficacy beliefs on behavior through intentions when normative support is low should be confirmed using experimental methods.


Self-confidence Social support Group norms Fruit and vegetable intake Discretionary choices Nutrition 



We thank Caitlin Vayro and Daniel Brown for their help in data collection.


Martin S. Hagger’s contribution was supported by a Finland Distinguished Professor (FiDiPro) award from Tekes, a Finnish funding agency for innovation.

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.

Ethical Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed Consent

Informed consent was obtained from all individual participants included in the study.

Supplementary material

12529_2017_9685_MOESM1_ESM.docx (27 kb)
ESM 1 (DOCX 26 kb)
12529_2017_9685_MOESM2_ESM.docx (16 kb)
ESM 2 (DOCX 16 kb)


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Copyright information

© International Society of Behavioral Medicine 2017

Authors and Affiliations

  1. 1.School of Applied PsychologyGriffith University and Menzies Health Institute QueenslandMt GravattAustralia
  2. 2.Health Psychology and Behavioral Medicine Research Group, School of Psychology and Speech PathologyCurtin UniversityPerthAustralia
  3. 3.Faculty of Sport and Health SciencesUniversity of JyväskyläJyväskyläFinland

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