I trained 3 times a week (various running exercises) dropped beer, bread and chococlate and managed to shift 2 stones (12.5kg?) in 4 months.
I trained 2 times a week, using the bike, x-trainer, treadmill and rower, kept the beer and bread but dropped the chocolate and last 1 stone (6kg?) in about 7 weeks.
Slow and steady wins the race. You need to stick at it to get results.