Angel34,
I am kind of working with the same theory that you are. I have always been very active and slim, but never ate the right things. So, I am correcting that and hoping that I will lose the extra flab that I have never been able to get rid of while keeping my breasts. Wahaika always suggests that anyone starting an NBE program should lose the extra weight in unwanted areas, because it acts like a magnet for the herbs. So, my thoughts based on this are that if I lose the extra little bit that I need to lose while maintaining my breast size, the herbs will have very few places to go outside of my breasts, so most of them will go there. Very amateur theory on my part, but I figured it couldn't hurt.
I run 3+ miles 3-5 days a week, do pilates twice a week (love it!!), and various calisthenics on the days that I do not have pilates. After working out, I notice that my fattier areas are freezing cold (good sign) like my thighs and tummy, but my breasts are SO WARM! I take this to be a good sign.
As a matter of fact, I have noticed a vast increase in the sensations and pains in my breasts since I started eating clean and training a month ago. I haven't had growing signs in ages!!
I think exercise is super important. I always knew diet was a big deal, of course, but I never ate right. I feel amazing now, so I don't think I'll ever go back to eating the way I did before. I feel as though eating clean has really contributed to starting the process back up for me.
Sorry for being long-winded, but the long and the short of it is that I have been testing this theory this past month, as well! So far, I would say that it is a great one.