Appearance is subjective, and most of the ladies that choose this industry are far more accepting of a man's physical "faults" than we are of theirs. As you already stated, you're not talking about a lack of hygiene, but a less-than-ideal body image/appearance. That is usually irrelevant to most SPs so long as you're polite, respectful, and don't weigh 300+ lbs and want to climb on top (they don't want to be crushed to death).
Having a rippling six-pack and a movie-star face *might* help you get slightly more enthusiastic service (once again, looks are subjective),
but these ladies aren't in the business to be seduced or fall in love: they're here to make money, ideally have fun, and definitely keep their personal and professional lives separate; i.e. NOT get romantically attracted/involved with you.
So go to it, be a well-groomed gentleman, and enjoy!