It would defintely appeal to middle aged women wanting to lose weight but now you just need to get your PR up so they can find you. My mom is actually loosing weight and she is middle aged and I can tell you they hardly care about the design. I recently showed her a website I sold for $50 (.psd) and she was like who would pay that much for a website. I didnt even start to elaborate to her. Anyways the design is simple and fast loading, which thanks to John Reese that's all it needs to be.

Good luck.