Animal rights activists are warning consumers that foods advertised as healthy might have something else surprising in common: animal testing. What’s more, there’s almost no way to know for sure.

Experimenting on animals has become more common for food companies in the last decade, says Justin Goodman, director of the laboratory investigations department at People for the Ethical Treatment of Animals, a group actively engaged in ending animal testing. And those tests, he says, are “almost exclusively to establish marketing claims.”

As reported by National Geographic earlier this month, pasta company Barilla banned animal testing after being criticized for contracting out experiments to assess whether consumption of durum wheat boosted omega-3s. The purpose of the study was to try and establish