I (Male in his 20s, 5'11'') currently weight about 240 Lbs, coming from 320 Lbs at my heaviest. This has largely been achieved through reduction of calories (around 1500-2000 a day, on average) combined with walking (around 4.5 miles a day at around 3 MpH). I've been doing this for just over a year, with a couple of months gap around Christmas due to life circumstances.
For me, this seems to work out just fine, as can be seen by the 80 Lbs weight loss. However, lots of advice I see on here suggests that walking is not enough.
My current concern, still being about 60 Lbs overweight for my height, is weight loss, not muscle building. Am I doing more harm by only walking and losing weight than I would be incorporating weight lifting into my exercise regime?
I see the virtues of running extolled in various places, but I seriously doubt I could run for more than say 5 minutes continuously, while I can walk for hours, which largely seems to be linked to the stress the extra weight puts on my body.