To explore adherence to a plant-based diet from the perspective of goals- and motivations-based systems.

A cross-sectional, survey-based study was conducted regarding eating patterns, goals and motivations for current eating habits.

Data were collected using an online survey platform, including the Goal Systems Assessment Battery (GSAB) and other survey tools.

University students were recruited, including thirty-three students reporting successful maintenance of a plant-based diet (Adherents) and sixty-three students trying to adhere to a plant-based diet (Non-adherents).

Using GSAB subscale scores, discriminant function analyses significantly differentiated adherents v. non-adherents, accounting for 49·0 % of between-group variance (χ2 (13) = 42·03, P < 0·000). It correctly classified 72·7 % of adherents and 88·9 % of non-adherents. Constructs including value, self-efficacy, planning/stimulus control and positive affect were significant and included in the discriminant function. Logistic regression results suggested that participants who successfully adhered to a plant-based diet were seventeen times more likely to report ‘To manage or treat a medical condition’ as motivation and almost seven times more likely to report ‘To align with my ethical beliefs’ as motivation compared with non-adherents. However, these participants were 94 % less likely to report ‘To maintain and/or improve my health’ as motivation compared with non-adherents. Controlling for motivations, hierarchical logistic regression showed that only planning as part of the GSAB self-regulatory system predicted adherence to a plant-based diet.

Values-based approaches to plant-based diets, including consideration for ethical beliefs, self-efficacy and proper planning, may be key for successful maintenance of this diet long-term.