She could consider reading Anti-Cancer diet by Dr. Serban Schreiber or some of Dr. Fuhrman's anti cancer suggestions, specific foods touted as anticancer. I switched after whipple to agave syrup and stevia/erythritol (looking to limit dextrose in latter) and went low fat foods, very minimal animal protein unless natural. Even american cancer society event said more plant based. I eat fish/shrimp/scallops, minimal poultry. After whipple, goal is frequent small meals, stabilizing weight, soon after can alter diet more. I initially had more protein like greek yogurt then organic or non-dairy yogurts (latter more likely). Attitude helps too. Good luck. She hopefully does radiation and chemo too if didn't do them prior. I did whipple and chemo-radiation then chemo and dietary/supplement/exercise for early stage (1B) related ampullary and am clean at 2 1/2 yrs but my view is whipple is not likely to be enough though health of patient considered, and exception might be some stage 1 patients. Should ideally have 2nd top opinion.