Well, you could open a juice bar... however, you might want to make a provision in your lease that if the gym closes, they let you out of your lease. I was almost in a pickle last year when I was gonna open a juice-shop/protein shake place in a strip mall across from a 24hr fitness. A week after I had lined up the $$$, the gym announced their lease was up and they were closing. lol.
Are there any MaxMuscle's in the area? Or even a VitaminShoppe?