Do I need to enable an app like Jawbone UP to access the Apple HealthKit data on my iPhone?
Yes. There is a permission process for apps that connect to Apple Health that will enable the app to have read and/or write access to HealthKit data. The process will begin in the iPhone app itself, such as the Jawbone UP app, and will be viewable on the Apple Health "Sources" page. The Apple Health app will also allow you enable or disable a specific app's read or write permissions.
Apple Health Settings -> Privacy -> Health Example: