What's the reference to Kidney problems all about?
Somehow, high protien puts a lot of stress on the kidneys and makes them work harder. I'm not sure what the mechanism is but I have a friend who constantly had to watch out for that when she did low carb.
I've found eating lots of veggies helps replace the wheat type carbs and helps control my appetite better. Keeps you regular, too, which is a problem on high protien diets.