You are again assuming incompetency with gathering data. Your counter example is about non-chronic condition (common cold) so it doesn't really relate as the ev

You are again assuming incompetency with gathering data. Your counter example is about non-chronic condition (common cold) so it doesn't really relate as the evidence is stronger with chronic conditions. With gluten and gluten-free you can also go back and forth and see how things change. Also bloating isn't a vague symptom. You can put measuring tape to your belly and see the numbers.