not a girl but posting for my girlfriend

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Well, first of all you cannot really tell if the girl has large breast or not - it could be photoshop, push-up bra, lighting etc.
Then you have to keep in mind that this is true for every pic/tv-show/advertising you are going to see on the web or tv so that most of us have a distorted perception of beauty already.
If you lower your bf percentage your body will loose fat everywhere - not in the same speed or at the same time but it will come off everywhere in the end. So there may be a few genetically gifted women on this planet who may still have relatively large breast while also being at a relatively low level of bf. But for the rest - cosmetic surgery. And just to make that very clear: the "being genetically gifted" part has to be questioned. Not every women/girl wants to have large breast - and believe it or not, not every male (and i believe this is true for women to) on earth is attracted by large breast.

Don't make it sound worse then it was.   I read the post your talking about and in no way were you told to F-off.

Unfortunetly  the "porn star" look is unattainable through natural process.  you want low body fat but big boobs?  doesnt work that way read here
 http://www.askscooby.com/womens-fitness/exercise-does-not-increases-your-breast-size/

One reason many dont like the girl from what is it, the  "body rock" videos? is b/c she used to be a porn star and has breast implants.  it sends a msg that If you follow her work outs then youll look like she does.

Here's me levelin with you.   you have a few options and ill tell my personal opinions on each
1) get low body fat and have implants - not my cup of tea.  as a guy I'd rather be feeling up the real thing then silicon.
3) natural giant breasts of eating like shit getting huge but you'd have a big but and big breasts - also dont suggest this b/c unhealthy and is viewed as unatractive
2) Work out lightly, enough to bring in your core and strengthen your back (which does infact make breast look bigger even if the don't actually get bigger) - and accept that you aren't going to have a 6-pack and know that you will still look HOT - if you couldnt tell this is the one I suggest.