Attractiveness to relationship ratio

Does anyone of you know wether it is easier to get a relationship if you look attractive? I mean I know it makes sense that more people are interested into you. But how does that raise the chances for a real relationship with someone who actually likes you, and not only the way you look?I myself look average and am thinking to work out to increase my chances. But I am afraid that the only thing I will attract then would be people only interested in looks...