Just one snippet from the highly relevant debate going on in the Daily Mail presently.
Look here
and here
Personally, I have let myself go physically recently, because I have three children under five, one with health problems, and I just haven't got the time or the inclination at the moment to invest a lot of time and/or effort in my appearance. Things might well change in the future.
But to make any assumptions about my intellect as a consequence...