This advice is based on the logic that “bad” combinations overwhelm the digestive system, preventing the foods’ nutrients from being properly absorbed and contributing to digestive upsets. Our digestive system, by contrast, likes things simple. The beauty of the human digestive system is that it’s designed explicitly for that mixed diet. Since different food components get handled in different areas and by different enzymes, we don’t have to eat our foods one at a time. Returning to your question, many of us may have found that certain foods or food combinations work best for us.