Encouraging words sometimes aren't enough to get someone to work out -- sometimes, a good visual is a lot more powerful. In my opinion, this ad for Gold's Gym could have been drawn with the signs reversed as well.
As this image implies, you walk into Gold's pinner, you walk out a buff and built stallion. Reversing the signs would convey that when you're overweight and hit up golds, you walk about slim and trim.
Check out some more unconventional fitness ads: