I have both conditions and was told to limit bananas, tomatoes and nuts. Potassium and phosphorus are the culprits and you can google them for a complete list.

It is difficult to advise on decreased kidney function diet as diabetes diet clashes with it, you really need to see a nephrology dietician to help with what you can or cannot do. Diabetics cannot eat white bread, renal failure cannot eat brown bread, this is one example and apparently there are many other restrictions that clash, if you have decreased kidney function you are most likely being followed by a Nephrologist who can send you to a dietician that they usually deal with