Foods are devided into groups based on the required environment for them to be digested. Meats and high proteine foods rquire acids while fruit and starches need an alcaline environment. When foods are mixed the stomach can't handle the task and undigested foods make there way into the lower intestine and feed the bad bacteria. Some of the proteines are absorbed into the bloodstream and can cause an immune responses and allergy as well as inflamation. The blood becomes sticky and cannot flow properly.