Most of us know what a healthy life looks like. More movement, better sleep, a balanced and varied diet, reduced stress. Many of us even have a pretty detailed knowledge on the principles of healthy eating etc (hi!) . However, for most of us, just because we know something doesn't mean we will do it. And more than that, just because we intend to do something, also doesn't mean we will do it.

This gap between what we intend and what we actually do has a name in health psychology called the intention-behaviour gap. It has been studied, not only in the context of health behaviours (such as eating, exercising etc.), but also in other aspects, such as recycling. In the context of health behaviours, it has been shown shown that the correlation between an intention and the actual behaviour is only moderate. This means there must be other factors at play that influence whether an in intention is acted upon.

While simply knowing doesn't help

Firstly, once we know something, we need to have an intention to actually use that knowledge and create a change. Secondly, once the intention is formed, no matter how strong, there are a number of factors that then influence whether or not we take action.

  • Two systems, one brain. Our behaviour is shaped by two processes running in parallel: a deliberate, reflective system (where intentions live) and a faster, automatic system driven by habit, emotion, and impulse. When we're tired, stressed, or distracted, the automatic system tends to win. Good intentions are a product of our thoughtful selves, but often our actual behaviour isn't.
  • Intentions don't come with instructions. Forming the goal "I should exercise more" is very different from deciding exactly when, where, and how you will do it. Without a concrete plan bridging intention to action, the intention tends to fade when the time for action comes.
  • Context keeps changing. We form intentions in one state, often calm, motivated, and sitting down, then have to act on them in a completely different state. Stress, fatigue, temptation, and opportunity all vary from moment to moment, and our behaviour varies with them.
  • Self-regulation is a limited resource. Even when we genuinely want to act on an intention, doing so often requires overriding a competing impulse. That overriding takes effort and our capacity for it is limited, especially later in the day or under pressure.

What actually helps

Understanding the intention-behaviour gap is more useful than it might first appear, because it shifts the question from why do I keep failing with my great intentions? to what can I do to make successful change more likely? As outlined above, there are few things that we can do to help bridge the gap: forming specific implementation plans, building positive habits so behaviour becomes automatic rather than reliant on willpower, and designing environments that make the healthy choice the easy one.

Also realising that we are all human, and this is how our brains work. Sometimes we just need to cut ourselves a little slack!