As mentioned above, running is the best way to lose weight and get fit. Im well into my running and run to a decent standard at club level, and simply cannot put on weight. I do a terrific amount of running and walking mind.
If you haven't done any running before try a beginners 5km programme like this one below or you can look for a harder one. I would strongly recommend the Park Run Time Trial which is held every Saturday at 9.00am at Blackwier off Western Avenue near Tesco Extra. It has a huge range of abilities, and best of all its free!
http://www.parkrun.org.uk/cardiff/homeWEEK ONE
Mon Rest
Tue Run 1 min, walk 1 min. Do 10 times
Wed Rest
Thu Run 2 mins, walk 4 mins. Do 5 times
Fri Rest
Sat Rest
Sun Run 2 mins, walk 4 mins. Do 5 times
WEEK TWO
Mon Rest
Tue Run 3 mins, walk 3 mins. Do 4 times
Wed Rest
Thu Run 3 mins, walk 3 mins. Do 4 times
Fri Rest
Sat Rest
Sun Run 5 mins, walk 3 mins. Do 3 times
WEEK THREE
Mon Rest
Tue Run 7 mins, walk 2 mins. Do 3 times
Wed Rest
Thu Run 8 mins, walk 2 mins. Do 3 times
Fri Rest
Sat Rest
Sun Run 8 mins, walk 2 mins. Do 3 times
WEEK FOUR
Mon Rest
Tue Run 8 mins, walk 2 mins. Do 3 times
Wed Rest
Thu Run 10 mins, walk 2 mins. Do twice then run for 5 mins
Fri Rest
Sat Rest
Sun Run 8 mins, walk 2 mins. Do 3 times
WEEK FIVE
Mon Rest
Tue Run 9 mins, walk 1 min. Do 3 times
Wed Rest
Thu Run 12 mins, walk 2 mins. Do twice then run for 5 mins
Fri Rest
Sat Rest
Sun Run 8 mins, walk 2 mins. Do 3 times
WEEK SIX
Mon Rest
Tue Run 15 mins, walk 1 min. Do twice
Wed Rest
Thu Run 8 mins, walk 2 mins. Do 3 times
Fri Rest
Sat Rest
Sun 5K Race! (Park Run)