The notion that being overweight can impact our health and that lifestyle interventions are beneficial is nothing new. However, a recent study focusing specifically on brain aging has demonstrated that lifestyle interventions leading to just a 1% decrease in body weight can be associated with reducing “expected brain aging” by almost nine months.

Overestimation of brain age refers to when our brain appears older than expected at a given age. This is found not only in individuals with Alzheimer’s disease and depression but has also been observed in cases of obesity. Our understanding of the neurological problems associated with obesity is improving, and studies have shown that it can be associated with reduced brain volume and altered connectivity, meaning changes in the connection or relationship between brain regions.

But researchers in the current study asked whether this form of brain aging be slowed or even reversed.    

To address this, Gidon Levakov, a former Ph.D. student at the University of the Negev and colleagues including Galia Avidan, a professor of cognitive neuroscience at Ben Gurion University of the Negev, and Prof. Iris Shai of Ben-Gurion University of the Negev, an adjunct Professor from the Harvard School of Public Health and an honorary professor at the University of Leipzig, Germany, along with her former graduate student Dr. Alon Kaplan, set out to understand what interventions, such as dietary and lifestyle, could slow this brain aging.

“With global rates of obesity rising, identifying interventions that have a positive impact on brain health could have important clinical, educational, and social impacts,” wrote the researchers in their paper.

Brain imaging to estimate aging

Magnetic resonance imaging (MRI) uses magnetic fields and radio waves to create internal pictures of our body. In the case of the current study, they used it to view participants’ brains.

Levakov and team used this technique to calculate expected brain age from the images of many healthy people to get an understanding of how much the brain is expected to age over time. Researchers then observed brain age of obese subjects before and after an 18-month healthy diet and exercise program to determine if their brains had aged as much as expected. They termed the difference between the expected and observed aging as “brain age attenuation”.

“We observed that a lifestyle intervention in individuals with obesity resulted in a reduction in brain aging. Specifically, we found that a 1% reduction in body weight led to the participants’ brains appearing nearly 9 months younger than expected after 18 months,” explained Avidan in an email.

“Additionally, these improvements in brain aging were associated with positive changes in other biological measures, such as decreased liver fat and specific liver enzymes,” Avidan added. “Moreover, our analysis of food consumption reports completed by participants indicated that reduced consumption of processed food, sweets, and beverages was linked to attenuated brain aging.”

In the 20 years from 1990 to 2010, the amount of processed food consumed has almost tripled. With such increasing consumption of these types of foods, these findings are highly relevant in today’s society. But for many, life is busy and time is scarce, making adopting a healthier diet more challenging. Add in rising food prices and cheaper and more convenient foods can easily become a staple diet. 

“An important outcome of the study is the need to reduce the consumption of red meat and processed food, as this aspect of the diet was correlated with reduced brain age,” Avidan clarified.

Even small efforts can lead to significant changes

Working towards better individual and societal health, she went on to explain how healthier choices could be made for those on a lower budget. “This could be achieved even with low income by replacing such food items with better ones that are not necessarily expensive, [for example], legumes (although this was not tested in the current study), which contain protein and eating more fresh vegetables and fruits in general,” she said.

As for exercise, Avidan noted that even small daily measures, such as walking or climbing stairs instead of taking the elevator, have beneficial effects and could be incorporated into a busy schedule.

The researchers acknowledge more studies are needed to conclusively determine the long-term effects of obesity on brain aging. “Evaluating factors such as cognitive function, mental health, and overall well-being would provide crucial insights,” said the team.

“Additionally, exploring the long-term effects of lifestyle interventions on brain aging and investigating the specific components of these interventions that contribute most significantly to the observed improvements are important avenues for future research,” added Avidan. 

The study’s results create much needed awareness of the beneficial effects of diet and exercise on brain aging and how it can be reversed. Although conducted in an obese population, the researchers hope that their study as well as future studies will also benefit  the wider population and the development of guidelines for public health initiatives.

Reference: Gidon Levakov, et al., The effect of weight loss following 18 months of lifestyle intervention on brain age assessed with resting-state functional connectivity, eLife (2023). DOI: 10.7554/eLife.83604

Feature image credit: Kaylee Garrett on Unsplash