This story starts in an unusual place for an article about human nutrition: a cramped, humid and hot room somewhere in the Zoology building of the University of Oxford in England, filled with a couple hundred migratory locusts, each in its own plastic box.
It was there, in the late 1980s, that entomologists Stephen Simpson and David Raubenheimer began working together on a curious job: rearing these notoriously voracious insects, to try and find out whether they were picky eaters.
Every day, Simpson and Raubenheimer would weigh each locust and feed it precise amounts of powdered foods containing varying proportions of proteins and carbohydrates. To their surprise, the young scientists found that whatever food the insects were fed, they ended up eating almost exactly the same amount of protein.