Hi, Noted your history of having watery black diarrhea looking like undigested food and smells bad after eating beef. This simply indicates that you have severely intolerant to something in beef that your intestines can not tolerate. So the first part of treatment is to stop eating beef and any other products high in protein value. Get stool tested for three consecutive days and if any positive findings then get treated accordingly. Colonoscopy and biopsy. Tests of blood particularly for thyroid and liver functions. Ultrasound of abdomen particularly for pancreas. All these things will lead to a proper diagnosis and proper management. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. T. Chandrakant, General Surgeon