Once nutrition has been optimised, and if significant weight loss is stabilised then it is reasonable to concentrate on making the diet as healthy as possible, and considering supplements to optimise the bodies health state.
I do not support severe calorie restriction diets in my patients, as this can be frankly dangerous in patients with gastrointestinal malignancy, many of whom already struggle with weight loss. Cutting out sugar completely can lead to significant weight loss and also other physiological problems. In general, radical diets of any type not healthy. There is certainly a role for potentially altering diet during cancer treatment, but this should be done moderately and in conjunction with the dietitians and your oncologist.
There may be a role for ketogenic diets in certain very specific situations, please discuss this with the dietitians and oncologist. This needs to be done under medical supervision.
Generally, I recommend a balanced, healthy diet with a mixture of proteins, fats, carbohydrates and vitamin supplements. Sometimes, dietary fibre may need to be reduced to prevent diarrhoea, especially after bowel surgery and during pelvic radiotherapy.
