The article is not just saying fat != healthy. There are some good comments to takeaway about how fat affects the brain, e.g.:
" Fat cells also secrete substances that cause inflammation; chronic inflammation of the brain, which is often found in the obese, impairs learning and memory and is also a feature of Alzheimer’s."
No question that being fat isn't healthy, but I don't think there is much of a practical take-home from this. People already know that.