High-Carb, Low Protein Diets Lead to Better Mental Health

Using mice subjects, researchers found that high-carb diets might be far more beneficial to brain health than previously believed.
Shelby Rogers

In recent years, low-carb / high-protein diets have taken over health and wellness discussions. However, a recent study conducted by the University of Sydney could flip those discussions around. 

The team reported that there are substantial improvements to overall health and brain health in mice that were fed low protein / high carbohydrate diets. 

The findings, published in the journal Cell Reports, contributed to a growing debate as to the role food plays in brain health -- particularly neurological diseases like Parkinson's and dementia.  

"There are currently no effective pharmaceutical treatments for dementia - we can slow these diseases, but we can't stop them - so it's exciting that we are starting to identify diets that are impacting how the brain ages," said lead author and Ph.D. candidate Devin Wahl.

Benefits of high carbohydrate eating

The research showed for the first time how unrestricted low-protein, high-carb diets have protective benefits to the brain. The Sydney team likened it to the benefits of calorie restriction.

Previous research about calorie restriction suggested it could improve overall brain health and longevity.


However, there's one key point of difference between humans applying this research to their lives and the study itself. Calorie restriction isn't sustainable in humans. 

"We have close to 100 years of quality research extolling the benefits of calorie restriction as the most powerful diet to improve brain health and delay the onset of neurodegenerative disease in rodents," said Wahl.

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"However, the majority of people have a hard time restricting calories, especially in Western societies where food is so freely available."

While it's not sustainable in humans, replicating the results between calorie restriction and high-carb eating was encouraging to the researchers. 

"It shows a lot of promise that we have been able to replicate the same kind of gene changes in the part of the brain responsible for memory that we also see when we severely restrict calories," said Wahl.

As the Sydney team noted in their findings, high-carb diets aren't new by any means. Many cultures around the world sustain their energy from beans, rice, legumes, and vegetables rather than meats and fats. 

"The traditional diet of Okinawa is around nine percent protein, which is similar to our study, with sources including lean fish, soy and plants, with very little beef.

Interestingly, one of their main sources of carbohydrate is sweet potato," said Professor David Le Couteur, Professor of Geriatric Medicine at the University of Sydney.

Transforming mice diets

To see just how high-carb diets affected the mice, the research team fed them complex carbs from starch as well as casein protein -- commonly found in milk and cheese. 

They then tracked the mice's brain activity, particularly the hippocampus. 

The hippocampus is the part of the brain responsible for learning new things and memorization. However, it's typically one of the most critical in maintaining healthy brain activity. 

The researchers tested just how well the mice did with the diet through spatial awareness adn memory tests. They noted several improvements in both male and female mice of various ages after being fed the high-carb diets.

"The hippocampus is usually the first part of the brain to deteriorate with neurodegenerative diseases like Alzheimer's. However, the low-protein high-carbohydrate diet appeared to promote hippocampus health and biology in the mice, on some measures to an even greater degree than those on the low-calorie diet," said Couteur.

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