These calculators use an average burn based on weight, and again , every body varies.

So feel free to describe any plausible situation where OP can burn 3 pounds a week based solely on less than substantial exercise. Could it be 10 miles a day? Yes. Could it be 8 miles a day? Yes. Of course it could also be 20. You're getting so caught up in the fact the numbers vary--something I myself gladly stated before you ever inserted yourself into the conversation--while ignoring the larger point that there is no reasonable explanation that doesn't involve an incredible amount of walking/cycling.

The OP lost 12 pounds in a month. It is possible they did this just with exercise.

Yes, a tremendous amount of exercise. I covered that literally in my first sentence after "congratulations!".

They are getting out, getting fit, and probably raising dopamine/cutting stress related cortisol with the constant activity and adventure.

And how are you suggesting I've said that's not happening and that it's not a good thing? I literally both started and finished with praise for what he's been doing.

You are giving them advice they never asked for and could potentially not even apply to them.

So we're not allowed to comment on anything unless posters specifically ask for advice? That's not how forums work. OP is of course more than willing to ignore what I wrote if it's of no use to him and I take no offense at that. But I also wrote it for the countless people that are reading this thread. The fact my comments have been significantly upvoted tells me people did in fact find the information useful.

Personally I think it's important for people to have a reasonable expectation of what to expect from playing a game like Pokemon Go. And the reasonable expectation is that you're not going to get incredible results without putting in an incredible amount of work--that's true whether we're talking about Pokemon Go or any other exercise. Generating a 1,500 calorie per day deficit with no other changes requires a lot of exercise, any way you cut it. More for some people than others, but particularly with light exercise like walking we're talking hours.

let the OP be happy about their new activity level and health improvements regardless.

There is nothing in my comments that should keep the OP from being happy about their new activity level and health improvements. The only person that is taking exception is you. For some reason you seem intent on taking my comment negatively, despite the fact I went out of my way to make it clear I was very positive on what OP has done.