When using the Xcode 8+ and creating a new blank project, the following logs appear when running the application:
2016-06-13 16:33:34.406093 TestiOS10[8209:1
A tweet had the answer for me - https://twitter.com/rustyshelf/status/775505191160328194
To stop the Xcode 8 iOS Simulator from logging like crazy, set an environment variable OS_ACTIVITY_MODE = disable in your debug scheme.
It worked.