Eating processed, sugary, or fried foods is the number one habit that can lead to premature brain aging and cognitive decline increasing your risk of dementia and Alzheimer’s disease. A new study published Jan. 7 in Alzheimer’s & Dementia: The Journal of the Alzheimer's Association observed that eating foods found in the typical Western diet can actually undo the benefits of the Mediterranean diet that’s been proven to be heart and brain  healthy.

According to Eat This, Not That!, researchers tracked over 5,000 people for 20 years and found that those who followed the Mediterranean diet that emphasizes fresh fruits, vegetables, whole grains, and fish while eschewing red meat, processed and fried food foods, had brains that were 5.8 years younger than the folks who strayed off the diet track.

“Participants with slower cognitive decline over the years of follow-up were those who adhered closest to the Mediterranean diet along with limiting foods that are part of the Western diet, whereas participants who ate more of the Western diet had no beneficial effect of healthy food components in slowing cognitive decline,” wrote the authors of the study.

Puja Agarwal, Ph.D., one of the study’s top researchers from Rush University Medical Center, told ScienceDaily that “eating a diet that emphasizes vegetables, fresh fruit, fish, and whole grains may positively affect a person’s health. But when it is combined with fried foods, sweets, refined grains and red meat and processed meat, we observed that the benefits of eating the Mediterranean part of the diet seems to be diminished.”

Agarwal further added that the “more we incorporate leafy greens, berries, olive oil, and fish into our diets, the better it is for our aging brains and bodies,” according to Eat This, Not That! More benefits and information of the Mediterranean diet can be found here.