Obesity has more than doubled worldwide since 1980—there are now more obese than undernourished people on the planet.
We’re often blamed for our poor food choices and lack of physical exercise. But is it really possible the entire western world just became a bunch of lazy gluttons all at once? When you are an adolescent your brain is growing, and if you are having a very large amount of sugar at this time, it could actually be changing how your brain is going to respond in later life.
Research shows that the high level of sugar and fat in many of the foods we consume are detrimental to our health, and take hold of our brains like drugs of addiction. So addictive are these foods that our brain actually directs more attention to them, than it does to traditional, healthy foods.
‘When people go on a diet and cut out sugar, they become irritable and stressed out about not having the constant influx of sugar, in the same way that somebody who’s decided to stop smoking might feel irritable and crave drugs that are rewarding,’ says Amy Reichelt, senior research fellow at the University of NSW School of Psychology. In the case of food, that reward is stimulated by a neurotransmitter called dopamine, which helps control the brain’s pleasure centres. When things like drugs, sex or food activate our brain’s reward system, dopamine is released.
‘One of my studies recently exposed teenage rats to a sugary solution which had the same sugar amount as a fizzy drink. We gave them this for two hours a day, every day, across their adolescence—the same as a kid picking up a can of Coke on the way home from school.’
Furthermore, the study highlighted the vulnerability of a rat’s brain during adolescence, which may have serious implications for teenagers who drink high-sugar drinks on a regular basis. Reichelt says that while scientists are yet to pinpoint exactly the mechanism through which poor diet affects the brain, she’s confident the experimentation of rats can provide valuable insights into human behaviour, given ‘rats have all the same chemistry as us’.
‘What’s actually happening to your neurons is that the brain is becoming inflamed.
‘Because there’s all this sugar and fat in the brain, this can be making our neurons hyper-excitable or causing oxidate stress, and that is then impairing cognitive function.’
‘That’s basically the main way that these diets are actually impacting on our brains,’ she says.
Brain specialist Dr Helena Popovic, however, says that in order to break the dopamine-fuelled reward system that sustains sugar addiction, it’s critical to weaken the brain circuit between the initial craving and the satisfaction of that craving.
‘The minute you get that craving or that addiction, there are a number of approaches. You can either try and focus on something pleasant … or do something that gives you pleasure. Even if you are only delaying it for a while, you’re weakening that circuit.’