As an ex-runner I must admit that i really enjoyed my years of cross country running, but like many others i paid the price with a damaged knee (the left one in my case)
As an alternative to this I find cycling in all its forms equally enjoyable , possibly more so insomuch as it takes me much further . see more country.... know what i mean?
And my knee is holding up well to the cycling.
Whatever you choose...... enjoy! as it is half the battle with weight loss to be motivated by your chosen programme.
regards Willi`c