Breast Cancer, Bypass, and Nutrition

I'm looking for info on nutrition after bypass surgery and breast cancer. Surgery was back in 2005. I just finished breast cancer treatments. I'm starting to gain weight for no apparent reason that I can find. Just before my diagnosis I was in the same situation and upped my protein drink intake in an effort to take off a few pounds. It was the only major change (for about 4 months) prior to my diagnosis. So, I'm questioning the role of protein shakes in my diet, but not sure what else to turn to. Did anyone find a nutritionist that was educated in both WLS and cancer? It seems that the information out there can be conflicting.