Background: Facilitating a transition to more plant-based and less animal-based diets would strongly alleviate the environmental impact of food, while plant-based diets can also decrease the health risks of excess meat consumption. So far, little is known about which underlying determinants can most effectively steer consumers to more healthy and/or sustainable food consumption. Gaining more knowledge about underlying determinants gives more insight into why certain interventions are effective or not in promoting healthy and/or sustainable food consumption among consumers. Scope and approach: In this systematic review real-life behavioural interventions are investigated that aim to promote more plant-based and/or less animal-based food consumption among consumers. The review focuses specifically on the interventions’ targeted determinants. In total, 48 articles (51 studies) are included in this review. Key findings and conclusions: The findings indicate that targeting individual determinants (such as increasing consumers’ level of self-regulation) or environmental determinants (such as modifying portion sizes) is relatively effective to promote more plant-based and less animal-based food consumption. Almost all included studies that aimed to increase plant-based food consumption focus on fruit and vegetables. This implies a need for future real-life intervention studies to focus on plant-based food consumption other than fruit and vegetables, such as legumes or whole grains. Also, relatively few real-life intervention studies have been conducted that focus on a decrease in animal-based food consumption, either separately or in combination with increasing plant-based food consumption. This review is registered with PROSPERO - CRD42019125314.