I've seen some people compare guys liking skinny chicks to girls liking tall guys and thats a sort of idiotic comparison.
Being fat says something about a persons lifestyle and more often than not says something about their personality. They are lazy, over indulgent, they don't like active hobbies etc. Weight can be controlled. If you say anything other than "Yes." to that statement you're just making excuses.
But a persons height is genetic, and has no bearing on what kind of person they are, girls call guys shallow for bagging on fat chicks but its perfectly acceptable for them to say "I'm 5'2, will only date 6'+" mostly "because I like to wear heels" and they don't think twice about how ridiculous their dating standards are.
Skewed standards is probably a big reason why good girls date douche bags and the rest are alone.
Oh and to OP, you might not rule him out if he was a bit overweight because thats obviously your problem as well, but I bet you would rule out a shorter guy.
Everyone has their hang ups, some more rational than others and I think weight is a rational hang up as it often reflects someone as explained above.