That's what I want to know too.

If she commits to it she can really trim down, it just depends on what her existing weight is.

As far as your relationship goes, just encourage her to join you in workouts and encourage her to eat a more healthy diet. The next time she says she wants to lose weight, look her in the eyes and say "lets do it". Make it a team effort, say you want to do more as well. Just avoid coming across as too judging or too forceful.

The way i see it, its not shallow to not date someone base on appearance. Attraction is alot, and without it, the relationship is doomed. You will constantly be looking at hotter girls as you see them, you will slowly become less happy, the other side will see it and make things akward and then since youve waited so long its akward as shit for a break up. I Never sleep with a chick if theirs no potential. It's just asking for trouble.

you could try being a racist/sexist/homophobe lol start saying really offensive shit and just turn her completely off so she dumps you ;)

Heres the secret to a good relationship: You solve your problems together.

It is incredibly shallow to dump her because of her looks. You can also help her lose weight. I'm sure shes not happy about it either.

If you do dump her, i dont know how old you are, but in a few years you will regret it. Finding a good person to be with isnt easy. The Miss pefect you are expecting most probably doesnt exist. You will end up alone if you're overly picky.

How long have you been seeing her?...Has she met any of your friends/family?...You can´t change the past,but if you really want to break up with her without hurting her (already low?) self-esteem, you could always make up a story, that doesn´t involve her physical looks, about why you don´t want to keep seeing her.

Is she doing anything to lose that weight? If she is, just wait and see how it turns out. If not, you could always say you find it awkward to be with someone that doesn't care care of her health.

It's hard, but If you can: be honest.

The reason you don't want to tell her the truth isn't because she's a "really nice and thoughtful" girl. It's because humans are selfish, and coming up with a stupid lie is simply easier than telling the truth that would make yourself look like a shallow guy.

Tell you're going to start a Ketogenic diet. When she asks what that is explain to her how it's all about eating fat in order to lose weight. She might try it.

I didn't ask for a lie to tell her.  I asked how to do it.  I don't want to hurt her feelings.  I've had break ups in the past but they were for more significant reasons.  I'll do it your way, though.  I'll say, "Sorry babe.  You're fat.  Deuces."  Everybody wins, right?

Oh, I'd say she was about a fat as the lady from "The Heat" and "Identity Thief".

Maybe there´s no way you won´t hurt her feelings due to you breaking up with her, regardless of the reason/the way you do it...if that´s the case, then what is less painful for her?...hearing the truth or a made up story that doesn´t involve her fatness?