And the best option I think actually seems to be <i>mass surveillance</i>. Just take that somewhat structured environment, where people stay all the time, and surveil the shit out of it. <i>Without telling the subjects</i>. Task a group of people to objectively observe and note what is being eaten and how it affects people&#x27;s health. A pure observation like this could provide a lot of useful data, that would be free from biases introduced by subjects underreporting things or simply changing their behaviour because they know they&#x27;re being studied.