According to TV Guide Magazine, Susan Mayer, played by Teri Hatcher, is the most transformed character when they slip fast forward into the future flash episode.
Eva Longoria Parker, who plays the socialite Gaby Solis said, “Teri was on set the other day getting fitted for her fat suit.”
So, Susan will be a chunky old woman in the future!
On the other hand, Dana Delany who plays Katherine Mayfair, will not join the others in transformation. Her character will be locked up in a loony bin.
Source: TV Guide Magazine