Department of Humanities, University of Naples Federico II, Naples, Italy.
Department of Philosophy, Sociology, Education and Applied Psychology, University of Padua, Padua, Italy.
Appl Psychol Health Well Being. 2024 Feb;16(1):80-101. doi: 10.1111/aphw.12470. Epub 2023 Jul 12.
The Mediterranean diet (MD) is one of the healthiest and most sustainable food regimes. Nevertheless, MD diffusion is still limited, emphasizing the need to understand the psychosocial factors that could predict and promote its adoption. Starting from an integrated model of Theory of Planned Behavior (TPB) and Self-Determination Theory (SDT), the present randomized controlled trial investigated the effect of manipulating motivation (autonomous vs. controlled) on intention and MD adherence behavior. Participants included 726 Italian adults randomly allocated to one of three conditions: autonomous motivation manipulation, controlled motivation manipulation, and control group. TPB variables were measured immediately after manipulation (T1), while MD adherence was evaluated 2 weeks later (T2). Results from multivariate analyses of variance highlighted that participants in the autonomous motivation condition reported higher intention and a more favorable cognitive attitude than control group participants. However, no change in behavior was found. Moreover, a path analysis with mediation effect showed that the impact of autonomous motivation condition versus control group on intention was mediated by cognitive attitude. Findings support the integration of TPB and SDT to encourage intention to adhere to the MD, also suggesting that prompting autonomous motivation may help to promote a greater diffusion of this healthy and sustainable dietary pattern.
地中海饮食（MD）是最健康和最可持续的饮食方式之一。然而，MD 的普及仍然有限，这强调了需要了解可以预测和促进其采用的心理社会因素。本随机对照试验从计划行为理论（TPB）和自我决定理论（SDT）的综合模型出发，研究了操纵动机（自主与控制）对意图和 MD 依从性行为的影响。参与者包括 726 名意大利成年人，他们被随机分配到三个条件之一：自主动机操纵、控制动机操纵和对照组。TPB 变量在操纵后立即测量（T1），而 MD 依从性在两周后评估（T2）。方差的多元分析结果表明，自主动机条件下的参与者比对照组的参与者报告了更高的意图和更有利的认知态度。然而，行为没有变化。此外，具有中介效应的路径分析表明，自主动机条件与对照组对意图的影响是由认知态度介导的。研究结果支持 TPB 和 SDT 的整合，以鼓励遵守 MD 的意图，也表明提示自主动机可能有助于促进这种健康和可持续饮食模式的更大普及。
