Below are screen shots from my S Health app taken off the Note 4. If I had updated my weight the measurement would be added to the activity page. I have also included screen shots from the other options available.  Whilst S Health does tie you into the Samsung eco system it does work for me.

You can use the app with or without a Samsung wearable. Naturally I am using my Gear S.

I hope Samsung opens the app more to third parties as it has potential but needs to improve as Apple Health kit is leagues ahead. But this app does what I need so I am happy at the moment.