I like men with some meat on them... a 'gut' isn't the least bit unattractive to me.
That being said... there is a point when it is too big.
However, I know guys have a hard time believing this...
But, imo, women really are not as concerned with appearances as men are. We really can find ourselves attracted to men based almost entirely on personality.
For an example:
I had a professor in law school who was about 5'7" - 5'8", balding, weighed probably right around 180-200 lbs, (had a bit of a gut). He looked a little bit like Jason Alexander (George from
Seinfeld). Almost every woman in my class agreed that there was just something really sexy about that man. It was his intelligence, confidence and charisma that made him attractive to us.
So really, don't stress about that so much. If you feel that you would be more confident with yourself if you lost weight... then by all means, work on it. I know that losing weight did LOADS for my confidence (still have a ways to go). But other aspects of my life supply more confidence - things that don't seem as precarious to me.
For another example of a guy I think is cute, despite his gut...