I know some of you have this. It's more prevalent among the lardass sedentary folk among the population 'cause of how long they stay with their hips bent at a 90 degree angle (i.e. seated).
Go check now in a mirror. If you're ass sticks out like a baboon's and your stomach is arched forward like a preggo, congrats, you have hyperlordosis and likely some other related back issues.
You've probably found that a lot of clothes seem to hang off your back and front making you look overweight (or more so). And you may have knee, hip and back problems (lower back pain especially). Good news is that this shit is fixable in about 2-4 weeks.
http://forum.bodybuilding.com/showthread.php?t=130876763
All you need to do is the foam rolling and static stretches and a good 50-75% will be corrected in a week. YOU CAN THANK ME LATER.