Guys aren't as shallow as we think they are. Yes, there are some bad apples out there, but most men are decent and will love a woman for who they are.
I know how you feel though, when I met my fiance I was obese and he was underweight. We probably looked silly together, but we cared about each other and that's all that mattered. Oh, and he made the first move! He asked me for my number and he was the one who set up our first date.
If the last time he saw you was at your starting weight, then I wouldn't be surprised if he comments or seems shocked at your appearance because you're smaller than the last time he saw you!
(He may not comment though, because he may be unsure of what to say without offending you).
Just relax and have a good time. Be yourself and if you and him are meant to be, then you will be.