Damn.. you really lost 100 pounds? Man that's awesome! That speaks to your dedication and grit. Women like that in a man. Maybe put that on your dating profile. Mention that you like working out and is into fitness. Mention that you lost 100 lbs so far and your proud of that achievement. Also the thing about dating and flirting is that it's much easier when people are chasing you or notice you first. It's important to notice when a girl is attracted to you or is at least receptive. Be well groomed, put some effort into your dress and have open body language. Walk with you your back straight, don't avoid eye contact with people in you line of sight. Don't force eye contact with people. Everyone has their own walk/gait, do what feels comfortable to you while maintaining an upright posture. I don't know how best to say this, but the guys who tend to be successful with dating girls are the ones who aren't particularly looking for a relationship. They're the guys who are just doing them, focusing on their career, psychical health, mental health, etc. They are guys who are also aware of the signs that a girl is interested in them and can act accordingly, utilizing a bit of game.