Defense mechanisms are a common reaction to social activism. With global protests such as the Occupy movement, and increasing urgency of climate change action, defense mechanisms in response to activism are a pertinent area for research. Three hundred sixty three participants viewed environmental, health, and ethical arguments in favour of reducing meat consumption, then completed measures of belief in the arguments, attitudes towards meat, and intentions to reduce meat consumption. All three arguments were effective at producing attitude and intention change, but the ethical argument was the most effective and most believable. Belief in the arguments was a major factor influencing the extent of attitude change. Decreasing belief in the arguments over time indicated participants reacted defensively in response to multiple arguments.