Best way to lose weight without sports/running.

I've lost 40lbs and I primarily walk. I also have a crappy back and have often stopped weight loss/fitness routines in the past because of injuries. I was determined not to get injured this time and it has worked.

I highly recommend walking if you can't do anything tougher. I do 5 miles 5 or 6 times a week at 4mph. Now that I'm stronger I've added in a Treadclimber (cardio machine) and just started doing strength training once a week.

Anyway, walking has been great for me, I highly recommend it!