Perhaps a lot of misunderstandings could have been prevented if we had a better description of the study to begin with.
UCI MIND The 90+ Study - UCI MIND
Researchers have published many papers; here are some of the results:
1) People who drank moderate amounts of alcohol lived longer than those who abstained.
2) People who were overweight in their seventies lived longer than normal or underweight people did.
3) Over 40% of people aged 90 and older suffer from dementia while almost 80% are disabled. Both are more common in women than men.
Point #2 uses the term "overweight". That's a BMI of 25 to 29.9 That's what I would call "overfat", and likely to keep a person from making it to 80 or 90 in the first place. And, if they do make it, they will either have dementia or be otherwise disabled.