From what I've seen women are rather incapable of creating a stable environment for themselves, they're constantly worrying about something, have a tendency to overreact constantly, gossip out of insecurity, and generally live a life of mental chaos. Men on the other hand are very good at stabilizing their mental life, we're much less likely to be intimidated. Which is why I believe girls are much better at school (k-12) they're much more likely to do homework where as boys are much more likely to procrastinate with a disregard for consequences.
This helps explains why nothing is more attractive to a woman than a confident, mentally stable male. He symbolizes someone that can create a safe environment for her, someone that can free her mind from the constant chaos it's plagued with. You create an environment for her where she's not worried and scared of what's going to happen, an environment where she's mentally stable, and ready to have kids (or at least get in bed with you). This is why an alpha male is so attractive, he's the strongest most stable person in the group.
By attaching yourself to the belief that you must be potently attractive--you create a mental instability for yourself, thus repelling the woman of your dreams that needs that very stability to free her own mind. When you're talking to women you have to keep your mind stable and free of any concern. When there's a woman you're attracted to in your presence your attention should be entirely on her, ensure her comfort and pleasure and she'll ensure yours. The problem with most attractive men is that they're too ****y and unconcerned with the women they encounter they're full of themSELVES rather than female. The problem with most unattractive men is that they're too full of self doubt, they're concerned with the female but they're too unstable and their thoughts inhibit natural male conduct.
So before you go out and set yourself up for failure approaching women, develop that mental stability. Don't rationalize your feelings of self doubt, just awknowledge them and laugh at their novelty. Your weight is probably a manifestation of your pschological instability. I work at an airport and I see hundred of couples a day, and more often than not attractive women pair up with less attractive (although most definitely groomed) men.