Looking to eat healthier? It might be as simple as moving more.
That's the message from a recent study into the influence of exercise on eating patterns – and it's a powerful reminder of the psychology behind healthy habits.
The research, published in the International Journal of Obesity, looked at 2680 inactive young adults. The researchers found that after exercising for several weeks, these formerly sedentary people were more likely to choose healthier foods – fruit and veges, for example - while their cravings for fried foods, sugary drinks and other unhealthy options decreased.
The study participants were given exercise programmes to follow and were instructed not to change their diets in any significant way. But it happened anyway. It looks as if establishing one healthy habit can lead us – possibly unconsciously – to starting others.
This study didn't look into what might be actually causing this behaviour change, although it was noted that previous research has found moderate exercise can reduce a preference for high-fat foods in animals through changes in dopamine levels. Dopamine is a neurotransmitter that makes us feel good; we get a hit of it when we experience something rewarding.
It could be that the dopamine boost we get from exercising – a known mood-booster – makes us feel better than the expected reward we might get from eating that fatty snack.
Some studies have also shown a relationship between the intensity of exercise and the amount of appetite-regulating hormones in the body. Two hormones in particular – leptin and ghrelin – have been the focus of research, and it appears these are affected by intense exercise. Perhaps counter to what we might expect, exercising may make us want to eat less.
It makes sense that healthy habits don't exist in a vacuum. If we're used to one healthy practice, we'll likely be doing others, too. This will be familiar to anyone who's ever started on an exercise regimen in a bid to be healthier. Hands up who did this at New Year? We feel motivated; we clear out the junk from the kitchen; we're energised and bouncy; we eat well. But that can be hard to sustain if it's too intense. Hands up whose new year regimen has dropped off a bit, now?
So what's the secret to keeping it going and getting those positive habit changes sticking?
It might be simply not aiming too high. Small, simple changes we can sustain – so they become truly habitual – are going to be more "sticky" long term, than extreme, difficult or restrictive changes. Starting F45 and a low-carb diet and giving up booze and giving up caffeine all at the same time might feel good for a little while, but it's probably going to be hard to stick to long term - which is what we need to do if we want to continue to feel the benefits.
If you're struggling for motivation, perhaps simply starting to move the body – regularly, consistently; maybe start with a short walk each day – is a better route towards consistent eating habits and sustainable health.
• Niki Bezzant is editor-at-large for Healthy Food Guide www.healthyfood.co.nz.