jim, you've got less meat on you than kiery kightly

excersise more and eat the same
get off the bus one stop earlier than you normally do if you use the bus
wal to the shops and don't use the m3
visit a zoo or local attraction of a weekend so that you walk about the palce and tire yourself out
climb stairs rather than use the lift
simple things like that will help you get fit

lots of people think that they need to go to the gym and get buff to be fit, but they don't