One-Third of Cancer in U.S. Preventable Through Diet!

Hello, Everyone!
     While researching for my English Comp 2 paper on the importance of proper nutrition in preventing or slowing certain diseases and health conditions, I came across something interesting.  It was an article from 2009 in a spin-off of Science Magazine called Environmental Nutrition citing a Global Report stating in its findings that nearly one-third of cancers in the U.S., namely colon and breast cancer, are preventable through diet, physical activity, and weight management!  Wow!
     OK, now I understand the connection between diet and colon cancer - that seems pretty straightforward.  But diet and breast cancer?  The best that I can come up with is that breast tissue is mostly adipose or fatty tissue and, I suppose, a diet high in fat adds to that tissue, increasing the risk of breast cancer.  Either way, these results do give some food for thought, no pun intended!
Vicky