Diet's important too. Most of us eat wrong. Too much starch, too much sugar, eating too much at one sitting and eating too late.
If you're already active and serious about losing weight then don't eat anything that comes out of a bag or a box. Cookies, crackers, premixed potato/rice dishes/chips etc.
Low fat, low sugar, high protein, moderate starch. Cut back on beer and way back on soda.
Don't eat later than 3 hours before bed and try taking a walk after supper--it's good for the guts
Oh, and get laid as much as possible. Burns calories and boosts your morale