I'm 6'2" ~265 lbs (pretty fat) and around 30 years old. I started running to train for a 5k with some buds and found that I can comfortably run in zone 2 for about 1 hour with only mild soreness and minimal joint pain.

I've only really been getting into it in the past ~6 weeks or so, so still a beginner. Just wanted to chime in and say that running while fat is totally doable and you just gotta ease into it and try to avoid pain! Discomfort might be a part of the process, but running slowly in zone 2 has become quite relaxing and a great part of my day, despite having hated running when I was in the best shape of my life.

I used to only run in zone 4-5 because I focused on speed and just assumed misery was a necessary part of the running experience. It's been a total blessing to learn that it doesn't need to be like that at all!

Hope you can find a good balance for what works for you as a heavier person. Listening to your body and knowing your limitations are super important. Just wanted to share my experience as a heavier guy too.