Your brain might remember better where you left junk food than healthy snacks

  • Overcoming the junk food cycle is tough, and a new study might help us understand why 
  • According to the researchers, we remember unhealthy food items better than healthy ones
  • The team found an interesting link between our modern brains and those of our hunter-gatherer forefathers

Changes in our eating habits over the last few decades have caused junk food to creep into every corner of our lives. In fact, a 2015 study showed that unhealthy eating habits have been outpacing healthy eating in most parts of the world.

A more recent study offers further insight into our preference for junk food: our cognitive maps lead us to calorie-rich junk food more readily than to healthy snacks.

Scientists have termed this as the “optimal foraging theory” and have suggested it has its roots in more primitive times.

Their study was published in Scientific Reports.

Prioritising calorie-rich foods

According to the study authors, because our hunter-gatherer ancestors were never sure of their next meal, they had to bulk up on calorie-rich foods whenever they got the opportunity.

This meant that their brains developed mental "drop pins" that helped them locate this type of food more efficiently. For them it had many advantages – unlike in modern times.  

For their study, the team recruited 512 participants and tested their spatial memory. Participants were put through a maze of junk food and healthy food items, including chocolate brownies and potato chips, and apples and tomatoes.

While following a specific route, they had to look out for these 16 food items. However, in half of these samples, participants could only smell them. For the other half, they were able to taste and smell the food items. During this experiment, participants were unaware that their spatial memory would later be tested.

Participants managed to remember the whereabouts of junk food items roughly 28% better than they could remember healthier items, revealing that our spatial processing is biased towards high-calorie junk food items, the researchers wrote.

Previous studies showed similar results

This fresh study builds on previous findings which showed that participants categorised and memorised high-calorie food pictures more quickly than low-calorie ones.

Brain imaging of the participants in these studies also indicated that the high-calorie items engaged reward-processing areas of the brain.

A 2013 study, for instance, explains how participants’ spatial memory was boosted when viewing images of high-calorie junk foods, compared to images of veggies and fruits. This bias was also able to predict the BMI of the participants.

Researchers of this study understood that while our spatial memories evolved thousands of years ago, it is leading to unhealthy food habits and weight gain in “modern humans”.

The consequences of remembering junk food better

There is a lack of research into the topic of high-calorie spatial memory and its behavioural effects in a modern-day setting, but, based on available evidence, the human brain appears to focus on junk food more efficiently, which ultimately leads to us becoming more addicted each day. 

This might explain why we find it incredibly difficult when wanting to eat healthier and needing to make drastic dietary changes in the process.

“In this manner, the cognitive bias may facilitate high-calorie food choice, by capitalising on the tendency of individuals to prefer convenient, easily-accessible items when making food decisions,” the authors wrote.

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