Well, I actually did use whey protein mixed with skimmed milk for a couple of my daily milk drinks when I did my pre-op diet, although as Grace points out, you would need to make sure you don't overly increase your calorie intake if you decide to use them. Protein drinks are always a contentious issue...some PCTs recommend them, some don't. Personally, I found them a life-saver after my op when I really couldn't face eating much at all...at least I was ensuring I was getting in a good pure protein source, necessary to help repair and healing after the op. If I didn't have them, I simply wouldn't have got in any protein. I think if you at least have them in, you can see how you will feel after the op and use them if you feel the need.