iOS game size on the store

We are facing an issue with our new game download size on the store, we are using :
- Unity 5.0.2
- Xcode 7.0.1

After building the game with unity and archiving it in xCode, if we export the archive to ipa ( Save for iOS App Store Deployment , without app symbols), the ipa size is 39.4MB, but when we submit the game to App Store (through xCode organizer directly, or using the Application Loader with the ipa), Testflight shows the game size to be 172.9 MB !!!! which is...

iOS game size on the store