The RT team should offer you a diet sheet, and, if they don't, then ask for one. In short, it tells you to avoid fibre, green leafy veg, caffeine and alcohol - amongst a long list of other things.
For me, ignoring it was not my best move. The look of horror on their faces when I told them what I had for Christmas lunch!
If and when you have any bowel or bladder problems from the radiotherapy - which usually happens about half way through the course - then tell the radiologists and they will get something prescribed it only happened one one occasion for me so I didn't need anything.
I changed to decaff coffee and tea years before because of my bladder problems but would imagine the change would help - don't forget decaffeinated still has some caffeine in, if you want to avoid caffeine altogether drink water or some herbal teas such as rooiboos - red bush. Some people swear by drinking pomegranite juice too for urinary problems. Unfortunately chocolate also has caffeine in and some things are just a step too far for me - though I only eat two squares of chocolate a day.
I often look here for tips https://www.pcf.org/ the latest is bright coloured foods on your diet, anyway have a look, it’s the American McMillan equivalent.
