I also disagree with the fact that they started talking to him because they now saw him as someone to date. . . I know that myself, when I know men who have lost a significant amount of weight, it doesn't change the already established "Will I ever date this man?" evaluation. That happens pretty early on. The only time you can get past the fugly factor is within the first month, and in extreme circumstances (aka completely awesome personalities), up to a year.
In fact, I think that there is something about men who are a little overweight in terms of how much I feel they are a nice person to open up to. I feel this way about- whats his name- Al Roker(?) (the weather guy on Today). He was such a nice guy, and I feel like I could spill my heart out to him (dunno why), but now that he is skinny-minny, I don't feel the same way. But it certainly isn't because I am suddenly attracted to him! I still wouldn't date him. I can't put my finger on why I feel this way to start off with though.
With that said, weight loss will definitely increase the number of women who are just meeting you to be interested in you. So you will sill be a hunk to plenty of new women; probably just not to the ones that have known you forever and have never been into you!