my experience as a clinician working in the private sector with cancer patients and survivors, is that the provision of nutrition information is extremely poor and not evidence-based. Overweight patients are not told explicitly that their obesity and their sugar-laden diets can increase the rate of recurrence and/or progression, which is the case for most common cancers. Frontline staff (Macmillan nurses – sorry!) condone or even encourage unhealthy eating (just enjoy yourself – have a treat etc) which is more likely to increase tumour growth and metastases. Food provided in cancer units does not promote good health or good eating habits.
I have seen diabetic cancer patients that have never been told that their diabetes will hasten their cancer progression, and again the nutritional advice they receive is not evidence-based or clinically helpful.
Also the number of very overweight staff working in cancer care does not set a good example. Diet and obesity are the most readily modifiable cancer risks after smoking.