I am very sceptical as well because if there is a way to prevent kidney failure, the knowledge about it would be around the world within minutes, if not seconds.
Of course, there is the one or other diet which may help one person or the other, but generally speaking it is down to our own instinct and own research to find out what is suitable for us, especially since there are so many different reasons for kidney failure.
What helps in my case since pre-dialysis, dialysis and transplant is a vegetarian diet and everything is cooked/baked from scratch, no alcohol and no ready-made food and only very selected Restaurants, drinking lots of water (in my case from tha tab) and only buying coffee beans, never coffee powder etc.
Good luck wishes from Kristina.