<qa>  What is the effect of nutritional supplementation with whey protein on postoperative functional capacity inTo determine the impact of nutritional supplementation with whey protein on postoperative functional capacity in patients undergoing colorectal surgery for cancer.It is hypothesized that, compared with a control group receiving nutrition counselling only, patients receiving nutritional counselling along with preoperative and postoperative nutritional supplements will have a significantly improved change in functional walking capacity from baseline to 8 weeks after surgery. 