[Terr_]

Anecdata: I've lost 60 pounds in 12 months, simply just using free apps to (A) record my weight each morning and show a moving average (B) identify what surprisingly-high-calorie foods and snacks I was consuming.

...And no, the bathroom scale is completely non-networked, my smartphone simply prompts me to tap in the reading every morning.

If your goal is to "lose weight", then forget activity-trackers, because your main tactic should be controlling the input side. It's far easier to not eat 200 calories than it is to burn those 200 calories off later at the gym. It's also cheaper than buying expensive techno-nostrums / shiny-toys.