The scientific consensus is getting louder every day: eating a lot of meat is bad for the planet, and it’s also bad for our health. It’s estimated that meat consumption accounts for 18% of human-made greenhouse gas emissions, and we need to reduce meat intake globally to fight climate change. By some estimates, if we cut the planet’s farmed animal production by 50%, we could see a decrease in emissions by 24-40%. Yet the demand for meat products is projected to increase by a staggering 70% by 2050, largely due to population and income growth, especially in developing countries. This will lead to higher emissions while contributing to an increase in various types of cancer and cardiovascular disease.

One thing is clear: we need to get people to eat less meat. This means creating more effective policies and interventions that encourage people to reduce their meat intake. To do this, we first have to identify the driving forces behind people’s desire, or reluctance, to eat less meat. Previous research has shown the importance of socio-psychological forces when predicting people’s food choices; the data suggests tailoring interventions to consumers grouped by common characteristics in order to motivate behavioral change.

To find out how to most effectively encourage a more plant-based diet, a group of Swiss researchers set out to identify these motivations using the Theory of Planned Behavior (TPB). The TPB proposes that we can predict intentions and behaviors by looking at a person’s attitude (towards the specific form of behavior), social norms (what is viewed as right or wrong behavior by those around us) and perceived behavior control (how easy or difficult it seems to perform this behavior). In addition to these predictors, the TPB also takes into account expected emotions (towards the behavioral change), personal norm (the individual’s conviction that the behavior is right or wrong) and problem-awareness (understanding the importance of changing the specific behavior).

The phases of TPB include the pre-decisional phase (1), which is the re-evaluation of current behavior. An example would be the desire to be more ecologically responsible by eating less meat. The pre-actional phase (2) demonstrates the goal or intention of eating less meat in the future, and the actional phase (3) is the implementation of the behavioral intention. In this phase, the individual has to specify when and how this new behavior will be implemented, such as eating meat only once a week for dinner. Finally, the post-actional phase (4) is making the new behavior automated, essentially turning it into a habit.

The Swiss researchers conducted a survey which generated responses from approximately 1,800 randomly selected residents of the Swiss city of Lucerne. The survey measured the predictors and phases mentioned, as well education level, income and gender affiliation. The study highlights the importance of five predictors – personal and social norms, perceived behavioral control, problem-awareness and emotions – and the researchers offer suggestions on how to work with each of these predictors to make intervention most effective.

It’s no surprise that social norms play a big role when making the choice to reduce meat intake. One strategy that can persuade people to eat less meat is encouraging celebrities, opinion leaders, and other role models to demonstrate the benefits of a more plant-based diet, as well as their own commitment to this lifestyle.

Creating a positive perception of behavioral control is another important way to encourage people to make the behavioral change to eat less meat. The easier it is to reduce meat intake, the more likely people are to do it. One successful intervention is “Meatless Monday,” a project started in the U.S. that is now active in almost 50 countries. The initiative takes on many forms, but groups often provide information about healthy and sustainable meals, and suggest recipes.

Another way of encouraging meat reduction is to try to counteract the cognitive dissonance that exists in people’s personal norms: most people like animals and don’t want them to suffer, yet they eat meat that requires the suffering and death of animals. This phenomenon is called the ‘meat paradox’ and is challenging to address. Breaking away from the pro-meat framework is important, and offering healthy and tasty alternatives shows that meat isn’t necessary.

Further, the study shows that emotions are important motivators in the early phases of behavior change, suggesting that campaigns addressing emotions (such as guilt) may only be effective on people who haven’t yet thought about reducing their meat intake.

Finally, high problem-awareness correlated, not surprisingly, with a higher likelihood of wanting to reduce meat intake. Showing people the link between meat consumption and CO2 emissions, perhaps by providing an energy footprint calculator, could be helpful in creating awareness of an individual’s own contribution to climate change.

Perhaps not surprisingly, the study found that women and well-educated people have more positive attitudes towards reducing meat consumption, which is consistent with existing research. Women, in general, tend to be more willing to reduce their meat intake and may be more susceptible to interventions promoting this. People with higher education are also more likely to have awareness of environmental issues and to voice their concerns regarding these issues. Advocates can focus on empowering individuals through education to make good food choices, for their own health and the health of the planet.

The findings of this study can help animal advocates better understand behavioral change and the socio-psychological forces that drive it. This can help us design more effective policies and interventions that will encourage people to reduce their meat intake. In western cultures, meat is still promoted as the most important part of the meal. We need to work in a concerted way to move away from this idea, make people aware that their food choices have an impact, and offer attractive alternatives.