After reading your question, my gut reaction would be to ask your users. Maybe you've already polled/interviewed them, but if not, I think it'd be a perfect excuse to get to know your users better. I've spent a good amount of time talking with my users and found that there were quite a few assumptions that I was making that were far from true. If there's one thing I've learned managing product it's that sometimes you can't see the forest through the trees. In my opinion, it'd be interesting to have a conversation with people who were motivated enough to use your product, and ask them what would be the top three motivating factors in getting healthy. There is no better strategy when steering product design than to have a conversation with your users. My advice would be NOT to rely totally on yourself for the design of your product, but find a balance that works for your business of both internal design and external guidance (interviewing your users). Hope that helps!