Some find they are rather sensitive to those things and others aren't. I would say that it's best to determine if you have issues with them, as they do provide nutrients.
I think with the sweet potatoes, it has to do with the extra fiber that they provide, which make them a healthier choice.
Herb only treatment for Lyme & Bart ended 12/11 - no active symptoms for 2 yrs -Herb only treatment for Babesia ended 12/12www.healingwell.com/community/default.aspx?f=30&m=2977364
Had Lyme, Bart, Babs, RMSF, Ehrlichia, Myco, Anaplasmosis, EBV
New Lyme case 8/2014 - Healed 1/31/15 - unknowingly had Asymptomatic Babs and Asymptomatic Bart, being treated now though (2/2016)