Anyone looking to curb their bad snacking habits could have a new technique at their disposal: a new study shows that breathing in fatty food smells for more than two minutes is enough to put people off a high-calorie meal.

While the first sniff of a fat-heavy snack is likely to whet your appetite, the new research shows prolonged exposure to the smell actually works as a deterrent – and it could offer a new method of keeping you or your kids on a healthier diet.

The team behind the study suggests exposure to these initially appealing aromas is enough to trigger a reward in the brain that then leaves us satisfied.

It's almost as if we've snacked on something tasty… without the calories.

"Ambient scent can be a powerful tool to resist cravings for indulgent foods," says one of the researchers, Dipayan Biswas from the University of South Florida.

"In fact, subtle sensory stimuli like scents can be more effective in influencing children's and adults' food choices than restrictive policies."

Imagine how this could work in a school canteen or a supermarket: kids or customers could be nudged towards the fresh fruit section after two minutes of taking in the sweet aroma of baked cookies.

That's just one example but you can see the possibilities. As Biswas says, it might be a better bet than trying to be too regimental at meal times.

Using a scent nebulisers at a school canteen and a supermarket – discreetly disseminating smells like apples, strawberries, pizzas and cookies – researchers found smells of the more unhealthy foods (pizzas and cookies) made it more likely participants would pick a healthy food.

At the school canteen in the US, for example, where around 900 kids arrived for lunch, the number of unhealthy items picked fell to 21.43 percent with a pizza smell. That's compared with 36.96 percent for an apple smell and 36.54 percent for no smell at all.

Follow up lab tests matched the original findings, while also showing that a quick sniff of a scent had the opposite effect: those who only smelled cookies briefly were about twice as likely to pick an unhealthy food option as those who experienced the smell for more than two minutes.

Using a series of surveys, the study showed that the study participants who were better at recognising the smells were also more likely to be affected by them.

It's almost as if a quick smell of something tasty and indulgent primes the brain to taste it, whereas a longer smell is as good as eating it.

Ultimately, the brain may not be differentiating the source of the sensory pleasure, according to the researchers.

For now that's just a hypothesis about what's going on in the brain, but it tallies with previous research that our different senses can influence each other and that the senses of taste and smell are closely linked.

"We propose that this occurs because scents related to an indulgent food satisfy the reward circuitry in the brain, which in turn reduces the urge for actual consumption of indulgent foods," write the researchers.

One way the study authors suggest their work could be used is in getting kids to make better choices at meal times at school – a few minutes of pizza or cookie smells in the queue could have a more positive effects than a long line of posters telling them about the benefits of healthy eating, perhaps.

And this is an area of science that companies are already exploring – which is why you might notice the smell of something sweet on your next flight.

"In essence, if reward structures and areas representing craving in the brain can be satisfied with olfactory inputs instead of actual gustatory consumption of unhealthy foods, this can help with fighting food urges," concludes the team.

The research has been published in the Journal of Marketing Research.