Wow, you just told my life story about my unhappy marriage: grumpy wife, her significant weight gain and dominating personality, no sex, pressure to have kids, her jealousy about my running and dedication to staying in shape, etc., etc. Jeez, even your and her height/weight match mine and my ex-wife's.
Unless you have strong religious beliefs that divorce is sinful or wrong - get out, and divorce her asap!! No kids to worry about? Leave now! I regret not doing it way, way sooner than I did. Like you, we were not on the same page about many very important things with our lifestyle and future plans. I fell completely out of love with her. The main reason I waited was fear of what my family would think, and admitting failure. In the meantime I was miserable and while trying to make things work, there was no progress and we grew further apart...
Although I don't advocate taking the marriage vows lightly, I also relate to the terrible unhappiness and stress of being stuck with the wrong person - and to give up on life when you are so young would be a disservice to yourself and will affect your ability to have a positive influence on those around you.
I disagree with posters who said divorce is the last option. No way is it the last option. Staying married is the last option! I would only agree it was the last option if there was a kid involved, or again if you had deep religious convictions about it - that would change things completely. But otherwise, it is the best option at this point in time, and nothing to be ashamed of.
Since you are already out of love with her, you will bounce back quickly and be so much happier for it, almost immediately. I would hope your family and friends would respect you for it - probably right away, and certainly over time. More than likely, your friends and family already sense problems and are secretly hoping you will come to the conclusion that divorce is best before you get really stuck in a terrible marriage by having a kid. And you would be surprised how many of your friends who appear to have strong marriages are really faking it, and will reveal this to you after your break up.
There is such a thing as marrying the wrong person. It happened to me. It happened to you. Thankfully you are at a point in your life when you can extricate yourself from the marriage with a minimal amount of pain. If you are like me, the mourning of your failed marriage has already taken place through counseling and in your own thoughts - and once you are out you won't have any regrets and you will make a fast rebound towards a happy life!!