gluten intolerance has nearly 10x'd over the last 30 years

researchers wanted to work out whether this is due in some part to what's known as the "expectation effect," since people have been hearing a lot of demonization of gluten in society only recently

the researchers bring people into the lab, run tests, and gather a mix of participants that both do and do not have biological intolerances to gluten

they then sit everybody down and give them all the same meal. they tell everyone that the meal has gluten in it. (it does not, in fact, have gluten in it)

within minutes several people are running to the toilet with diarrhea, some breaking out in hives, inflammation, tension headaches...

no one in the room had eaten gluten

https://www.amazon.com/Expectation-Effect-Mindset-Change-World/dp/1250871093