How do we get people to change their eating habits?

OK, so now we know what a good diet looks like, how can we encourage people to change? Let’s start with education. Many countries have public health or school campaigns, but decades of research show that they’re not sufficient. For example, most UK citizens know that they should eat at least five portions of fruits and vegetables every day. This government campaign started back in 2003. But only a quarter of adults and 15% of young people in the UK follow this. So most people are not adopting a behavior with an immediate health benefit. This is a concern, because we know that health is a stronger motivator than protecting the environment. This brings us onto motivation.

As well as having the right knowledge, people need to be motivated to change. Changing one’s behavior, particularly if it’s become a habit or is the norm in your social group or if it’s driven by impulsive reactions to rewarding foods, is difficult. People need to be committed and they need to find new types of forms of rewards to stick out the new behavior. People also need to be in a social and physical environment that facilitates or supports the change. To take an extreme example, an Inuit Eskimo who only have access to meat and fish is not going to be able to eat a diet rich in fruits and vegetables.

Before we consider how to change eating behavior, let’s briefly consider what psychological processes drive our eating behavior. As a psychologist, I’m used to looking at both conscious and unconscious determinants of behavior. There are many models of how these two processes interact. One of the most widely accepted ones is the jewel process model. The model is simple and intuitive. You have your conscious system, that uses goals based on education and knowledge to drive deliberate decisions about what to eat. This is great, but it’s slow, effortful, and cognitively demanding. It doesn’t work so well at the end of a long day or when you’re distracted. Then you have your unconscious reactions.

These are composed of rapid automatic reactions that are more like reflexes. Behaviors that have been practiced many times are activated quickly in response to triggers or cues through this system. The cues can be internal, such as a mood state, or they can be external, such as seeing an advert for food. When these two processes are aligned, everything is fine. For example, you might have a goal to eat more fruit and see a delicious looking bowl of strawberries in your canteen at work. Both processes are pushing you to eat the strawberries, and you do. When the processes are in conflict, however, for example when you’re faced with the temptation of a tasty but unhealthy chocolate cake, then there’s a problem.

People try to rein in their impulses, but with varying success. Both the strength of our reward driven impulses towards food, and our ability to control them, are partly genetically determined. They vary widely between individuals, and many of us struggle to act in line with our goals. Therefore we need strategies and interventions that target both the conscious and the unconscious processes. Whilst education helps us set ourselves conscious goals about what we want to eat, it doesn’t prevent our automatic system from pushing us towards the fast food restaurant when we’re hungry. In order to resist the automatic drivers of behavior, we can do a number of things.

The most effective one is changing the environment so that temptation is out of sight and reach. In the home, this could mean removing or hiding less healthy foods, whilst making healthy ones visible and easily accessible. In the wider environment it’s a bit more difficult. Making foods more expensive or inaccessible is highly effective, but it’s unpopular, as it appears to conflicts with freedom of choice. One could argue that being constantly exposed to cues promoting unhealthy foods also interferes with your personal freedom, but that’s another discussion. Regardless, making changes to the environment requires regulation and changes in policy. And these can be politically and economically challenging and take time.

We therefore also need to equip individuals with some tools to help them control their own automatic responses. This is what my colleagues and I work on. We have developed a simple computer game that trains individuals to inhibit responding to foods that they would like to consume less of. It’s really easy to play. Images just flash up on the screen and all you have to do is tap on them as quickly as possible. However, when the image has a red border around it, you need to inhibit the response and you have to stay as still as you can. The red border appears with the foods that you want to avoid. And this trains you to associate those foods with stopping.

Our research suggests that playing this game makes these foods less liked, and easier to resist in real life. It also reduces the brain’s reward and attention response to these foods. You can try the game out for yourself. It’s available as a smartphone app called Food Trainer, or Food T for short. You can select categories of foods that you’d like to eat less of, so you might be trying to eat less meat or cheese, if you’re trying out the EAT-Lancet site for sustainability.