Rats are very useful for studying human eating behavior. Both rats and humans are omnivores, and both use flavor conditioning — learning through taste and experience which foods are good to eat and which to avoid. So if a particular flavor is associated with a desirable outcome like feeling full, this makes it more palatable, whereas a stomach illness would make it unpalatable.

Rats also share with humans many of the neurobiological and hormonal mechanisms of flavor learning and appetite regulation. Al…