Sorry, question, why do you say that potatoes have no nutritional value? Everything I have found seems to indicate potatoes are high in nutritional value (e.g. <a href="http://en.wikipedia.org/wiki/Potato#Nutrition" rel="nofollow">http://en.wikipedia.org/wiki/Potato#Nutrition</a>). I have also heard it said that it is possible to subsist entirely on a diet of milk and potatoes, as many Irish families did for quite a long time.