A Neuroscientist Explains What Sugar Really Does to Our Brains
AMY REICHELT, THE CONVERSATION, 26 DEC 2019
We love sweet treats. But too much sugar in our diets can lead to weight gain and obesity, Type 2 diabetes and dental decay. We know we shouldn't be eating candy, ice cream, cookies, cakes and drinking sugary sodas, but sometimes they are so hard to resist.
It's as if our brain is hardwired to want these foods.
As a neuroscientist my research centres on how modern day "obesogenic", or obesity-promoting, diets change the brain. I want to understand how what we eat alters our behaviour and whether brain changes can be mitigated by other lifestyle factors.
Your body runs on sugar - glucose to be precise. Glucose comes from the Greek word glukos which means sweet. Glucose fuels the cells that make up our body - including brain cells (neurons).
Dopamine "hits" from eating sugar
On an evolutionary basis, our primitive ancestors were scavengers. Sugary foods are excellent sources of energy, so we have evolved to find sweet foods particularly pleasurable. Foods with unpleasant, bitter and sour tastes can be unripe, poisonous or rotting - causing sickness.
So to maximize our survival as a species, we have an innate brain system that makes us like sweet foods since they're a great source of energy to fuel our bodies.
When we eat sweet foods the brain's reward system - called the mesolimbic dopamine system - gets activated. Dopamine is a brain chemical released by neurons and can signal that an event was positive. When the reward system fires, it reinforces behaviours - making it more likely for us to carry out these actions again.
Dopamine "hits" from eating sugar promote rapid learning to preferentially find more of these foods.