LONDON, ONT. -- The familiar expression is ‘you are what you eat,’ but new research out of Western University is putting a twist on that, showing that how you eat as a teen can define who you become.

A review paper released on Monday identifies how poor dietary choices in adolescence can lead to changes in the brain.

The paper has been published in the journal The Lancet Child and Adolescent Health.

Western researchers Cassandra Lowe, J. Bruce Morton and Amy Reichelt found that, as teenagers, people have a dual susceptibility – at an age when they are still developing decision-making capabilities they have limited restraint and heightened reward system - which makes them more prone to eating poorly.

The findings indicate that that may lead to changes in the brain that will contribute to obesity in adulthood.

In a statement released by Western, Lowe is quoted as saying, “Adolescents are more prone to eating calorie-dense, high-sugar foods because they lack the control to regulate it.”

Lowe is a postdoctoral fellow at Western University in the BrainsCAN research program.

“Their brain is still maturing so they’re more sensitive to the rewarding properties of these foods, but at the same time, they lack the control mechanisms to prevent themselves from eating junk foods.”

The paper notes that, during adolescence, the prefrontal cortex – involved in self-regulation, decision-making and reward-seeking – is still undergoing development, making it difficult for teenagers to stay away from unhealthy foods.

Until this area of the brain develops teens are more likely to engage in impulsive and reward-seeking activities.

“The prefrontal cortex is the last area of the brain to develop. It’s the part of the brain that is critical for behavioural regulation; it’s the manager of the brain,” says senior author Amy Reichelt, a BrainsCAN postdoctoral fellow at Western’s Schulich School of Medicine & Dentistry.

“The teenage brain has a triple-vulnerability – a heightened drive for rewards, reduced self-regulation abilities and susceptibility to be changed by environmental factors – including junk foods.”

The paper goes on to say that as adolescents overstimulate their reward systems, these unhealthy diets can result in poor cognitive control and heightened impulsivity as they move into adulthood.

They say this demonstrates the importance of changing behaviours and helping adolescents form healthy habits early on to minimize changes to the brain.

“One avenue that we really need to look into is the use of exercise as a way of regulating changes in the brain that can help us make better dietary choices,” says Lowe, a member of Western’s Brain and Mind Institute.

“There’s evidence that exercise can help improve the brain in terms of cognitive control, but also reduce reward sensitivity to things like food items.”

“Teenagers don’t want to be told what to do, they want to be able to make their own informed choices,” adds Reichelt. “If you provide them with easily understandable information about how their diet is affecting their brain, while providing them with other alternative behaviours, that’s going to help them in maintaining healthy lifestyle practices long-term.”

BrainsCAN is Western University’s research initiative in cognitive and behavioural neuroscience that aims to transform the way brain diseases and disorders are understood, diagnosed and treated.