Before RE5 Chris was last seen in CV. RE5- March 5th 2009 CV- December 27th 1998
And theres also the RE5 DLC Lost in Nightmares. It takes place in 2006, Chris is slightly less buff than in the main game. I don't have pictures for proof, so you'll have to check it out yourself. He was already kinda big in RE1 and CV anyway.
I'm just sick of people screaming "steroids" every time someone mentions Chris. What do you guys not understand? Do muscles frighten you?