It has long been thought that meat played an important role in the diet of hunter-gatherers before the Neolithic transition. However, due to the scarcity of well-preserved human remains from Paleolithic sites, little information exists about the dietary habits of pre-agricultural human groups. A new study challenges this notion by presenting compelling isotopic evidence of a strong preference for plants among 15,000-year-old hunter-gatherers from Morocco. This is the first time a significant amount of plant consumption has been measured for a pre-agricultural population, shedding new light on the dietary practices of ancient human societies.