McDonald's new Shake: sweet potatoe

After trying the regular shake at McDonald's a few months ago I've been trying a few of their seasonal editions. Since my short vacation in Tokushima where i first tried sweet potatoes  I fell in love with the taste.  Although Germany is famous for potatoes I have never tried sweet potatoes there. So when I found that sweet potatoes are quite common during fall season I was happy to discover that McDonald's also used them in their latest version of shakes. No question are these not really healthy (and environmentally friendly) but from time I do enjoy drinking a cup of those shakes especially since the S size only costs 120 Yen.