Sorry last post here,
but I ate, still do, very healthily. Because I have been living with breast cancer for many years I have made, met and lost some dear friends who like me were all stage 4. Some were younger than me, late 20's, 30's. Most of us were in our 40's and 50's. A couple of women were in their late 50's, early 60's.
We used to meet up all over the UK, after getting to know each other on a well known Breast Cancer Charity Forum. We made email contact with each other in 2004 and there were approx 40 of us. Then we started to meet in person, which was such a support, a boost. In January 2014 there was just 3 of us left. 
And like me the majority of them had been normal weight, healthy and active before their diagnosis.