Please mention your age so that its easy to point out the causes.
If you are having high blood potassium then u could be suffering from Kidney
or adrenal dysfunction or taking some drugs that cause it.
Diet which you shd avoid ---Wholemeal bread, wholemeal rolls, wheatmeal biscuits, muesli
, tinned spaghetti, cabbage (in coleslaw), gherkin, lettuce, onion, olives, tomato,Baked beans, red kidney beans, mushrooms, potato > twice per day, Apricots, bananas, custard apples, dates, figs, grapes, kiwi fruit, fresh peaches,rockmelon, rhubarb, tomato juice,Too much milk, cheese and yogurt, Chocolate, nuts, licorice, toffee & cocoa.
Hope this solves your query.
Please note both High & low Kalium are dangerous so you shd get regular blood testing & be in communication with your physician.