A higher fat diet seems to be good for preserving our brains and reducing the risk of dementia.
Here's another new publication from the PREDIMED study. It has previously shown that a higher-fat Mediterranean diet with extra olive oil or nuts is good for preventing heart disease and improving diabetes. Now it turns out it preserves cognitive function as well: Video report / Study
People in the study who were told to instead eat a low-fat diet did worse on everything. They got more heart disease, more diabetes and more cognitive decline. Don't eat a low-fat diet.