Studies like this can mislead women into a false sense of wellbeing- as most breast cancer cases clearly can't be prevented by the behaviors they describe. I hoped that avoiding alcohol would lower my risk, but I never believed that doing this would prevent me from getting breast cancer: all you can do is practice a healthy lifestyle, and hope for the best.
The majority, or 60% of breast cancer cases, are not influenced by someone's health habits, but it is still a good idea to practice healthy behaviors. I was thin when I was diagnosed, and gained weight during treatment; so, I'm happy that I didn't weigh 20 or 30 pounds more at the time of my diagnosis, or, I would be faced with losing even more now as I attempt to reach my precancer body weight.
Preventing breast cancer, unfortunately, isn't as simple as the study makes it seem. I would hate for other women to think that a healthy lifestyle will spare you: mine certainly did not spare me. Be healthy, yes; but most importantly, get screened on a regular basis; this is the health practice which could, and will, actually save your life.