Carrying extra fat around your waist raises your risk for multiple diseases, including heart disease and diabetes, and now a January 2019 study published in the peer-reviewed journal Neurology suggests that excess belly fat can also impact your brain.

In the study, researchers followed 9,652 participants with the average age of 55 and compared body mass index (BMI) to the volume of grey matter and the white matter in their brains. Grey matter is the dark tissue in in the brain and spinal cord that contains neurons and is where synapses are made, while white matter is made of nerve fibres that connect grey matter. As we age, the volume of grey and white matter in the brain decreases, which increases our risk for Alzheimer's disease and dementia.

Researchers found that participants with a high BMI-an indicator of obesity-had a much lower volume of grey matter in the brain compared to participants with a healthy BMI.

The results show that having a large waistline affects the central nervous system, but more research is needed to verify the correlation. "While our study found obesity, especially around the middle, was associated with lower grey matter brain volumes, it's unclear if abnormalities in brain structure lead to obesity or if obesity leads to these changes in the brain, Dr Mark Hammer, one of the authors of the study, said in a press release.

"We also found links between obesity and shrinkage in specific regions of the brain. This will need further research but it may be possible that someday regularly measuring BMI and wait-to-hip ratio may determine brain health," he adds.

But whether you're obese or not, it's still not a bad idea to keep your middle in check. "Belly fat is unfortunately the most dangerous location to store fat," weight management expert and gastroenterologist Dr Lawrence Cheskin, previously told Prevention. That's because belly fat is more active than any other kind of body fat and can circulate into the bloodstream, causing fat in your blood to rise.

That said, losing belly fat takes work. It requires you to consistently follow a healthy diet and exercise routine and a plan to reduce stress and get plenty of quality sleep each night. Want to learn more? Follow our guide on how to lose belly fat for good.