Excessive meat consumption is associated with health and environmental problems. Previous research has shown that the reasons for meat consumption are diverse and often include low self-efficacy beliefs in preparing alternative meals. In an experiment with 71 German participants, we investigated whether the delivery of meal boxes containing ingredients and recipes for three plant-based meals could increase self-efficacy, reduce meat consumption, and improve attitudes toward a vegan diet. No significant differences were found between the control group and the meal box recipients after the intervention. While recipients frequently liked the plant-based meals and could imagine preparing them again, the intervention did not increase their self-efficacy beliefs or affect their meat consumption. These findings indicate that the potential of meal box deliveries to alter dietary patterns may be limited.