When I when I first installed c25k, it wanted to know if I wanted to link to Google Fit and I said yes, but I didn't have Google fit on my phone. After I installed it, I was able to get it to accept c25k, but c25k never updates Google Fit.
I'd like to know how to take away the permission on c25k and then give it permission again, now that the Google app is on my phone - in the hopes that that will make it work. But c25k is not on Google fits list of compatible apps, so maybe it will never work.