eating sweet potato

This paper shows sweet potato starch extracted from human dental calculus. 

• Tromp, M. & Dudgeon, J. V. 2015. Differentiating dietary and non-dietary microfossils extracted from human dental calculus: the importance of sweet potato to ancient diet on Rapa Nui. Journal of Archaeological Science 54: 54-63. http://dx.doi.org/10.1016/j.jas.2014.11.024