Quick way to use same size font for all faces?

Hi

I have been using auctex for a number of years, but lately I've found 
that the faces in recent versions a little distracting - I'd like to 
revert all faces to using the same (default) font size (the other 
attributes are fine). Is there a quick way to do this, rather than 
having to redefine each face individually?

Thanks,
Jonathanm