It's a very confusing topic.  Some acidic type foods like lemons for instance are supposed to have an alkaline response in the body.  Generally speaking, meats, nuts and cheese allegedly create an acid load; fruits and veggies create an alkaline response.  However, some authors such as W. Wolcott of the Metabolic Typing diet believes that certain foods can have one response in one metabolic type and an entirely different response in a different metabolic type.  Anyone want to shed light on this topic -- my head is spinning from all the conflicting views on it.