I just want to preface this by saying that none of the things I will say are meant to offend you. They are merely just honest answers to the question posed. Okay? Okay.
The first thing that you have to consider is the fact that a lot of that initial attraction is based on physical attractiveness. Whatever your personality, people will almost always be initially drawn to you due to physical attraction. There's very little that you can do to change this - it's just simple biology. Therefore, due to the fact that you're not, by your own admission, conventionally attractive, people are less likely to notice you.
The second thing that you have to consider is the fact that people tend to like others similar to themselves. Thus, someone who spends a lot of time and energy in the gym and eating healthily is not likely to be attracted to someone who is, at least in some aspects, the exact opposite of that. Again, it's not impossible, just rather unlikely. Finally, even if they were willing to get pass it all, they would likely mind in the long term, seeing how it is something that could easily cause tension in a relationship.
My advice would be to take a long, hard look at what you want and how do you prioritize things in life. It is more than a little hypocritical to look out to date someone physically fit and attractive, while having a very different standard for yourself. Ultimately, I am of the opinion that it would be best, primarily for yourself, but also for your dating prospects, to try to eat healthier and lose weight.