Well, for the steps to be recorded you need mobile app. That shows advertising the advertising space can cost coins.
If the idea gets traction you may build up a community and a forum about being healthy, meaning bigger user base and more space for advertising - and again, advertising space costs coins.
The idea can be improved, but this can be a start, maybe.
I agree this is just a start but something I hope to build into something amazing one day, while I will say I hadn't thought of selling advertising space. As for selling the space for coins I'm not sure I could do that in the beginning as I would need to money that source could bring to help pay back the people I would need to help me get this idea off the ground but thanks for pointing some things out to me.