In order to assure that we regularly replenish and sustain our alkaline reserve, the best guideline to follow is the “80/20 Rule.” This simply means that 80% of the foods we eat should be alkaline- forming, and 20% acid-forming. This rule does not give us license to eat acid-forming foods that may be laden with toxins such as preservatives, artificial sweeteners and other unhealthy additives. But there are certain natural foods, such as cranberries and blueberries, that although acid-forming, can be helpful in keeping our kidneys and bladder clean.