I think that the best person to ask would be the consultant dealing with the case.
I would be wary of advice given on computer forums because we tend to be normal people like yourself who maybe have spent years battling with their own weight related issues...
If in your shoes - I would be inclined to check the internet to see if there was any advice that appeared to be from a reputable source... That would be worth considering and taking to discuss with your consultant.
For example -
I notice that it gives the following advice regarding protein:
PROTEIN
Low-protein diets may be helpful before you start dialysis. Your doctor or dietitian may recommend a moderate-protein diet (1 gram of protein per kilogram of body weight per day).
Once you start dialysis, you will need to eat more protein. A high-protein diet with fish, poultry, pork, or eggs at every meal may be recommended. This will help you replace muscles and other tissues that you lose.
People on dialysis should eat 8 - 10 ounces of high-protein foods each day. Your doctor, dietitian, or nurse may suggest adding egg whites, egg white powder, or protein powder.
Maybe your hospital / consultant has a website which gives information too. This for example is the website from my husband's consultant urologist.
I must emphasise that I am NOT a medical professional.
Good luck.